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Message started by BurnPgh on 06/02/10 at 22:27:16

Title: exhaust port
Post by BurnPgh on 06/02/10 at 22:27:16

Has anyone opened the exhaust port and kept the stock header? Any considerable difference? I know I should get a better header but im broke at this point. No more fun money to play around with, I dont know anyone that welds and is reliable, and Im tired of in depth tinkering. I can spend a little time clearing that lip out of the way but would it be worth it? If not I'll just wait until i do get the header situation figured out.

Title: Re: exhaust port
Post by LANCER on 06/03/10 at 03:20:44

I think opening the outside of the exhuast port is worth the little time it takes to do it, even if you are still using the stock header.

Title: Re: exhaust port
Post by earlytimz on 06/03/10 at 06:03:10

I can't give an accurate before & after, but I agree with Lancer. It's an easy job & I don't see any way it'll hurt your performance.
I opened the port up to match the size of the header ID & I also took off that crazy "ledge" inside.

FWIW... I didn't ride the bike much before I tore it down so like I said, it's hard for me to give a good comparison. I can tell you though, it will absolutely scream when you open her up now so I don't think it hurt anything! I've been porting heads on various machines for years & this is one of the easiest to do. There's lots of material in there, so you don't have to worry about taking out too much...

Some of the best performing port jobs I've seen were also the ugliest!!

Title: Re: exhaust port
Post by justin_o_guy2 on 06/03/10 at 07:31:04

Some of the best performing port jobs I've seen were also the ugliest!!



Ive seen that hold true in other areas of life.

Title: Re: exhaust port
Post by earlytimz on 06/03/10 at 07:46:53

LOL!!
You ain't a joking bro!!!

Title: Re: exhaust port
Post by earlytimz on 06/03/10 at 10:24:11

Don't forget to get rid of that stud on the intake side. Otherwise it's in pretty good shape. I cleaned up the casting seams a little too, but you don't want this side too smooth. That affects atomization & fuel drop out...

Title: Re: exhaust port
Post by klx650sm2002 on 06/03/10 at 11:17:38

To me the exhaust port is the worst thing about the savage, anything you can do with it would be good.
Clive W :)

Title: Re: exhaust port
Post by JohnBoy on 06/03/10 at 11:37:33

If you choose to do it, would you take pictures for us of before and after?
Please...please...please! :)

Title: Re: exhaust port
Post by BurnPgh on 06/03/10 at 11:39:27

If you want before and after pics search "lancer upgrade" with the search function for "all posts". If you want to see a serious port job before/after search "clutch slippage on tuned savage"

Title: Re: exhaust port
Post by Chief Gunner on 06/03/10 at 12:40:58

BurnPgh I checked the two posts you recommended.
Other than the pics on lancer's showing the lip at exit being opened up, is there any additional 'meat' that could be taken out that would improve the flow? I'm running stock pipe with and HD muffler. I'll be doing some extensive engine clean up and if a mod like this will improve the performance I have the tools and the time.
Would like to see some before and after pics so I don't go too far and punch through anywhere. I tend to get carried away with power tools!  ;D

Title: Re: exhaust port
Post by BurnPgh on 06/04/10 at 00:33:29

whoops. the second thread i recommended wasnt the one i thought. Its one of Kwaknut's more recent posts but IDK exaclty where its at. I'll see if i can find it.

Title: Re: exhaust port
Post by Chief Gunner on 06/04/10 at 08:05:15

found a thread entitled exhaust port back in 07, it had a lot of pictures attached but the links have expired.

Lancer / Savage Greg / klx650sm2002, this discussion was between you guys. You don't happen to have those pictures saved anywhere do you? Any lessons learned?

Anything would be appreciated. As always thanks!

Title: Re: exhaust port
Post by LANCER on 06/04/10 at 09:29:42

VALVE AREA ... BEFORE

http://images1.snapfish.com/232323232%7Ffp343%3Enu%3D323%3A%3E639%3E697%3EWSNRCG%3D32336%3A%3B2%3B%3A354nu0mrj

http://images1.snapfish.com/232323232%7Ffp346%3Enu%3D323%3A%3E639%3E697%3EWSNRCG%3D32336%3A%3B2%3C773%3Anu0mrj


EXHAUST PORTS ... BEFORE

http://images1.snapfish.com/232323232%7Ffp343%3Enu%3D323%3A%3E639%3E697%3EWSNRCG%3D32336%3A%3B2%3B%3A35%3Anu0mrj

http://images1.snapfish.com/232323232%7Ffp33%3B%3Enu%3D323%3A%3E639%3E697%3EWSNRCG%3D32336%3A%3B2%3C7744nu0mrj

http://images1.snapfish.com/232323232%7Ffp33%3B%3Enu%3D323%3A%3E639%3E697%3EWSNRCG%3D32336%3A%3B2%3B%3A365nu0mrj


EXHAUST PORTS ... AFTER




http://images1d.snapfish.com/232323232%7Ffp39%3A%3Enu%3D323%3A%3E639%3E697%3EWSNRCG%3D3235944255477nu0mrj


VALVE AREA ... AFTER


http://images2.snapfish.com/232323232%7Ffp53242%3Enu%3D323%3A%3E639%3E697%3EWSNRCG%3D3236%3B89%3A68629nu0mrj

http://images2.snapfish.com/232323232%7Ffp53239%3Enu%3D323%3A%3E639%3E697%3EWSNRCG%3D3236%3B89%3A69836nu0mrj



INTAKE ... AFTER


http://images2.snapfish.com/232323232%7Ffp53238%3Enu%3D323%3A%3E639%3E697%3EWSNRCG%3D3236%3B89%3A664%3B8nu0mrj

http://images2.snapfish.com/232323232%7Ffp53242%3Enu%3D323%3A%3E639%3E697%3EWSNRCG%3D3236%3B89%3A6495%3Cnu0mrj

Title: Re: exhaust port
Post by klx650sm2002 on 06/04/10 at 10:07:09

Lancer, are the valve springs above that horizontal bit in the top of the port, how much is it safe to take off there ?
Clive W :)

Title: Re: exhaust port
Post by ralfyguy on 06/04/10 at 10:26:45


525F505D5B4C0C093E0 wrote:
http://images1d.snapfish.com/232323232%7Ffp39%3A%3Enu%3D323%3A%3E639%3E697%3EWSNRCG%3D3235944255477nu0mrj

Ok dumb question: Is this before or after?

Title: Re: exhaust port
Post by klx650sm2002 on 06/04/10 at 10:32:39

Looks like after to me. It's upsidedown too.
Clive W :)

Title: Re: exhaust port
Post by ralfyguy on 06/04/10 at 10:42:50

So where is the piece to grind off?

Title: Re: exhaust port
Post by klx650sm2002 on 06/04/10 at 11:17:39

The round bit just inside the port, mostly gone in that pic.
Clive W :)

Title: Re: exhaust port
Post by Truckinduc on 06/07/10 at 19:09:06

here these pics I took might help. This is just to remove the ring.  If you are careful you can do it with the motor all together.

Before

http://i35.tinypic.com/242dh.jpg

After

http://i36.tinypic.com/4keetf.jpg

Process

1. remove exhaust and battery ground.

2. turn over motor by hand until you hit compression stroke.

3. Make sure exhaust valves are fully closed and seated.

4.  spray a Little shaving cream in to the valve area.

5. stuff paper towels into each port.

6. Port head with whatever tool you prefer, like a die grinder or dremel. I port matched mine to my exhaust. Thats the shiny ring in the first picture.

7. vacuum all shavings out. If any got past the paper towels the shaving cream will catch them. Vacuum it out too.

8. Re install exhaust and battery, your done.

Really not that hard if you take your time and be careful.

Title: Re: exhaust port
Post by LANCER on 06/08/10 at 04:37:08


545347090A0F4C520D0F0F0D3F0 wrote:
Lancer, are the valve springs above that horizontal bit in the top of the port, how much is it safe to take off there ?
Clive W :)


Yes, the springs are on the other side of that "wall"

Not sure exactly about how much was removed...did not measure; just went by "feel"; I wanted to be sure to have enough material to maintain structural integrity.
I did not remove much, just enough to round off what was a sharp pointed peak before.

The most important part of the process was to smooth the area just below the valves and to round out the "inside corners" within the ports.  These were hard to get to and nearly impossible to photograph.
I used emery cloth torn into narrow strips and run through the ports so I had an end  to grab hold of on each end of the port; then did a back-n-forth motion (like flossing teeth) and repeated it for the medium/med-fine/fine grits that I had available.
The ehaust follows the shortest path in the ports and that requires that the inside corners be as smooth as possible to reduce any hindrence of the air flow
That was my goal at least...we shall see if I did this correctly or not.

I was following the technique of a Harley dude with some reputation for building world record engines for the salt flats.  I figured he must know something about it and so went with it.  Of course, it would have been helpful to have the good tools and some time to develope proper technique under his direct guidance....but you go with what you've got.

Title: Re: exhaust port
Post by Bubba on 06/08/10 at 07:21:31

Truckinduc, what did you notice as far as performance improvement doing just the exhasut port?

Title: Re: exhaust port
Post by bill67 on 06/08/10 at 08:05:39

anytime you make ports bigger you lose on the low end power and gain on the high end.

Title: Re: exhaust port
Post by ralfyguy on 06/08/10 at 10:52:03

So it's like putting a free flow muffler on. How would it affect a stock carb jetting, spacer 2/3 and the baffle removed from the stock muffler like mine. It runs very good like that with smooth throttle transitions and pretty good power up to about 90mph. Problem is, I was thinking about doing the exhaust port job, but don't have the guts, because I don't know how the effects will be. What if it totally ruins the way it runs now. There's no way back, other than a new head. Or I have to do all the other stuff with airbox and rejet and it never will be right. Will the theoretical gain be worth the try? Or would the difference not justify the risk? I am not that much of a hard core engine tuner. I like the idea of a better cam and stuff, but I don't think I'd be up to actually doing it. The spacer and exhaust mod, as well as doing the mixture screw already made it a 1,000 times better running than when I first got it. If I knew that the exhaust port mod would just give a little more ooomph without having negative effects, I'd go for it in a heartbeat. I just don't know how it's gonna be.

Title: Re: exhaust port
Post by bill67 on 06/08/10 at 11:05:56

Go up one jet richer on the high speed will give you more power,And you just have to drop the fuel bowl to do that.

Title: Re: exhaust port
Post by LANCER on 06/08/10 at 12:04:42

with the port a little larger, the exhaust moves a little more freely out of the engine; just like a HD muffler flows a little more air than the stock muffler; both result in a little more power.
More air (exhaust) out allows more air (fuel/air mix) in which makes more power.

same with the performance camshaft; the valves are open a little more and stay open a little longer, resulting in more exhaust out and more fuel/air mix in = more power.

all fun stuff......  ;)

Title: Re: exhaust port
Post by ralfyguy on 06/08/10 at 16:16:34

How about the low end? Right now it pulls from 40mph to 70mph in about 9-10 seconds in 5th gear on level ground.

Title: Re: exhaust port
Post by bill67 on 06/08/10 at 18:12:25

You will lose that low in power,And you'll have more on top if thats what you want.

Title: Re: exhaust port
Post by ralfyguy on 06/08/10 at 19:37:42

I guess I'll just leave it the way it is. I like the torque for mostly in town riding. It's got plenty of Hwy power already. Lots of people complain that it runs outta breath at around 70. I don't have that feeling. If I wanna go past a car on the Hwy, and I crack it open at around 70, I get past it fairly quick. Once I get back in the right lane, I look at the speedo and darn I'm at 90 already, and it wasn't downhill.

A while back a Dude on a 500 Ninja and I had it going on a red light. We took off and the Dude had his Ninja screaming, and after about almost 1/2 mile I had to throw the anchor at 95, not to miss my off ramp into town and the Ninja had about just 15 yards advantage. Sure the Ninja was faster, but didn't impress me at all. I was very surprised, because I expected to get smoked badly. To me that little Savage is a beast.  :)

Title: Re: exhaust port
Post by earlytimz on 06/08/10 at 20:58:56


373C39396362550 wrote:
You will lose that low in power,And you'll have more on top if thats what you want.


Sorry Bill... Bad info there
You are not gonna "lose" that low end torque. Here's how I know...

I did a midnight special port job on my head. I opened the exhaust side to match the factory pipe, also took off the ledge and smoothed everything out. Nothing really aggressive, just gave her a good massaging. I then hit the seams on the intake side & took off the protruding stud. This side aint too bad.

Now... I have a 150-90 rear tire which is quite a bit taller than factory. I also have a 4 speed trans (higher geared). To top it all, I think I'm still a little lean on my needle. So with all these things adding up you'd think I lost all my bottom end...

The result???
Well I can pull out of a curve at 30mph in high gear without a problem. I honestly wish I had a 5th gear because I have no doubt it would pull it. I'm in Ky, we have plenty of hills. I can hit any hill around here in 4th gear and pull all the way up. Even the one on my way home that requires me to drop down to 40- 45 because of a curve at the bottom of it. No problems whatsoever, just open her up and she grunts down and pulls like a diesel truck.

Yes, you need back pressure to optimize torque. Even with the porting, there is still a D shaped squeeze in that port. After that, you've got a tight bend in a small I.D. pipe, then most likely some kind of baffle in your muffler. There's no shortage of back pressure.

Trust me, opening up your head will not hurt your performance. That exhaust port is the most restrictive design I've ever seen on anything... EVER. That ledge is ridiculous! It's like a friggin parachute in there. Open it up & take advantage of a better scavenging effect. That's where the exhaust pulse creates a vacuum that pulls out the next pulse. It's the reason a 2 into 1 pipe makes more power on a v-twin. It also applies to big singles (& V-8's & 4-bangers, etc...) & is mostly affected by the pipe I.D., which isn't changing. You're just making it easier for the engine to push out the exhaust gases.

It's just like Lancer explained... More in = More out, More out = More in

It's an easy job. You don't even have to pull the head (although you prolly should) There's plenty of meat in there, you'd have to get really aggressive to do any damage. Check out the pics that have been posted, get a good bur bit & go to town. Take your time & be precise. You won't regret it.

Title: Re: exhaust port
Post by earlytimz on 06/08/10 at 21:33:05

Sorry, once I get going on something it's hard to shut my mind off...

This picture is hard to read but explains the scavenging effect, or exhaust driven induction effect, I was talking about. I know it says race motor (a motor is electric, btw), but that's because race engines are built to optimize power & torque, where factory engines are built for emissions & economy & they could care less about scavenging.

They describe it as a 5th stroke. It's the vacuum created by the exhaust pulse pulling out the next exhaust pulse, in turn pulling in the next intake pulse during the valve over-lap.

Confused yet? LoL... It's legit, it works... Open that head up and let it breathe!!!!!

http://i47.tinypic.com/2v12ij7.jpg

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 04:10:28

Earlytimz how must does that gain you in power and gas mileage?

Title: Re: exhaust port
Post by LANCER on 06/09/10 at 05:19:10

Good info.

I just want to add one more thing.  Don't think of opening the exhaust port as a RACE mod, it is an EFFICIENCY mod.
It is as if you took off your header pipe and found a big rock stuck inside, which you would naturally remove becasuse it is interfering with the exhaust getting out and would certainly cause a decrease in efficiency; or power.  Remove the rock and the engine works better and makes the power it was really designed to do before all of those rocks were thrown in by "gov't b'crats" at the EPA.
Rocks in the carb, rocks in the exhaust ports & header, rocks in the muffler...etc.
When I did the first mods on my Savage I removed those rocks and  cleaned everything up a bit; the result was that power went up to 42-45 hp at the rear wheel.   A stock LS650 makes about 25 hp at the rear wheel.
I had more power AND torque everywhere... from idle to a maxed out redline of 6500 rpm and it still wanted to do more.

Everything I did to my engine was to increase efficiency, until this last rebuilt...this time I went beyond that, but point is that there are fairly easy things that can be done which enable to engine to work easier and will yield more usable torque with which to play or to use when passing that big truck on an uphill highway or mountain road.

You will really like the result.

Title: Re: exhaust port
Post by earlytimz on 06/09/10 at 06:39:17

Hey Bill, I can't really put a number on it. I don't have a dyno or any fancy test equipment. It's just a matter of letting your engine work easier. I like the way Lancer described it with the big rock stuck in the way. You can also look at it like trying to blow through a coffee stir vs. a big straw. Your lungs are gonna force the same amount of air through both, but which one is faster & takes less force? Which exhaust port is gonna let your engine rev faster, with less resistance?


3C313E3335226267500 wrote:
I had more power AND torque everywhere... from idle to a maxed out redline of 6500 rpm and it still wanted to do more.

-And I bet it revved to the 6500 redline a lot quicker too!!

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 08:01:46

It will help the high end and get less mpg.And kill the low end power.

Title: Re: exhaust port
Post by Bubba on 06/09/10 at 08:11:29

Okay, I'll bite...I'm thinking this might be fun. If I take the header off and use a dremmel to take the lip off the exhaust what do I need to look out for?
I've never come anywhere close to modding an engine like this and my wrenching skills are basic at best (but everyone else calls me a "mechanic"...not even close!)

"It will help the high end and get less mpg.And kill the low end power."
Bill, I'm wondering...how do you qualify that statement? Have you tried it?

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 08:17:24

Do it and you will know too.

Title: Re: exhaust port
Post by Bubba on 06/09/10 at 08:23:20

Does that mean you've done it???
I'm a mile high here, I'm thinking I could use whatever extra air I can get but I don't want to lose out on the low end torque.

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 08:27:14

I had a snowmobile professional ported it killed the low end, A little bit of help on the high end, I never did it again and wouldn't.It also killed the gas mileage.

Title: Re: exhaust port
Post by Oldfeller on 06/09/10 at 08:42:20

Bill,

Was that snowmobile engine by any chance a two stroke engine?  
And jest for grins what sort of two stroke oil did you use in it, BTW ....

;D   ;D   ;D  

I knew you picked up on Klotz from inside the two stroke world from somewheres in your past.





Title: Re: exhaust port
Post by bill67 on 06/09/10 at 08:46:48

Your right on both counts.

Title: Re: exhaust port
Post by earlytimz on 06/09/10 at 08:47:35

Your snowmobile was probably a 2-stroke. 2-stroke engines use a finely tuned exhaust and are much more sensitive to mods... Plus they have no bottom end to start with, they are high revving engines. Think "Power Band"

We used to port the crap out of 2-stroke banshee & blaster heads. Did it help the bottom end?? Hell no, but when you open that sucker up and hit the power band you know you've done something good!

Title: Re: exhaust port
Post by earlytimz on 06/09/10 at 08:48:22

OldFeller beat me to it...

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 08:57:45

My young fellow 4 cycle motorcycles rev higher than 2 cycle,I've had 3, 2 cycle motorcycles.

Title: Re: exhaust port
Post by earlytimz on 06/09/10 at 09:04:53

3 cycle?? or 3 cylinder?

EDIT: I re-read your post. I think you're saying you've had three, 2 stroke motorcycles... I see that now.

I'm gonna have to disagree that a 4 stroke engine is higher revving. 2 strokers only have 1/2 the revolutions to make a complete cycle. They rev twice as fast.

Title: Re: exhaust port
Post by Serowbot on 06/09/10 at 09:40:06

Too much of anything can cause a problem... Porting, jetting, intake air, unbaffled pipe... whatever....
But, from the look of that exhaust port, with that shelf obstruction across the top of the port,... I doubt it's possible to get too much flow out of there...
I softened mine up a little, years ago,... with little effect, but I think I'll go back in and do a proper job soon...
I don't touch intake ports,... roughness in there is supposed to be beneficial... (that's what I've been told,..and I always do what I'm told  :-?)...

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 09:52:50


4C485B45505D404453290 wrote:
3 cycle?? or 3 cylinder?

EDIT: I re-read your post. I think you're saying you've had three, 2 stroke motorcycles... I see that now.

I'm gonna have to disagree that a 4 stroke engine is higher revving. 2 strokers only have 1/2 the revolutions to make a complete cycle. They rev twice as fast.

2 of the 2 cycles were 3 cylinder.Thats ok you can disagree that don't change anything.

Title: Re: exhaust port
Post by earlytimz on 06/09/10 at 10:09:03

So anyways, it's irrelevant which one revs higher or faster. The point is comparing a 2-stroke port job performance to a 4-stroke port job is like apples & peaches. They are two different animals and behave totally differently. 2-stroke engines have no bottom end, they have a power band, which is ALWAYS up there in the revs.

Bubba... If you really want to do this, find yourself a big washer that fits snugly inside your header pipe. You will use this as a guide to open up the exhaust port. You can take measurements and get all fancy, but the bottom line is that you want to match these up so numbers don't matter. If you don't remove the valves, stuff some paper towels down in there deep & tight, use compressed air to blow out the dust and filings. Grind a little all around, test fit your washer & make adjustments where needed. Go a little at a time. Once you've got it opened up, smooth everything out. You don't want any sharp or abrupt edges. Imagine how the exhaust gases are gonna flow & make it as smooth as possible. A dremel will be a slow process, but that's ok too. I use a bur bit, which will take off a lot of meat really quick-like. Then I finish up with a fine stone (dremel) to smooth it all out.
On the top of the exhaust port there is a big flat spot with a lip on it. You can see it in every picture posted, although you can't see the lip because it faces away from you. I call it "the ledge". Stick your finger in there and rake across it a few times, you will feel the lip. I removed a considerable amount of material there, but at bare minimum you will want to take off the lip and round off the flat spot so everything will flow smoothly. This is probably the hardest part of the job, but once you stick your finger in there & rake back a few times, it becomes obvious what needs to be done.

Serowbot is right on the money with the intake side. Roughness on the walls is better but you still want everything to flow smoothly. There is a stud protruding out right in the middle of the port & that cannot be good. It took me about 2 minutes to cut that thing down with a bur bit. It's a threaded stud, not aluminum.

The reason you want to leave the intake port walls rough is because of a phenomenon called fuel drop-out. That's when smooth walls let fuel droplets collect on them, then the droplets don't stick & just run down the sides and collect at the bottom. With rough walls, the fuel droplets kinda stick & are less likely to run down & more likely to be picked up by the air mixture surging by. Rough walls also promote more turbulence which helps atomize the air/ fuel mixture & therefore allow for a better, more complete burn in the cylinder.

On the flip side, get the exhaust port as smooth as possible. These walls aren't collecting any fuel droplets (hopefully). The idea is to make it as easy as possible for the gases to be pushed/ pulled out.

Now please don't take what I say as expert advice. Do some research on it. I'm not a professional by any stretch but I have ported several heads over the years from 2-stroke & 4-stroke quads, bikes, to air cooled VW's. Keep in mind my goal was never to increase fuel mileage, but to increase efficiency & power. This advice is only worth what it cost you!

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 10:14:43

You write to much I'm not even going read it,You already showed me you don't know what your talking about.

Title: Re: exhaust port
Post by Bubba on 06/09/10 at 10:21:27

earlytimz, thanks for the info. I've read here about exhaust porting and I've been curious about it (just becuz). anyway, I'll continue to research it (altho' it seems folks that have done it like it!) and may give it a shot over the winter when I have riding downtime. Right now the weather has been great here and I don't want to dig into it.
Thanks for the description...even if Bill didn't read it...I did...

Title: Re: exhaust port
Post by babyhog on 06/09/10 at 10:23:01


343F3A3A6061560 wrote:
You write to much I'm not even going read it,You already showed me you don't know what your talking about.


I think just the opposite Bill.  The more he writes, the more it sounds like he knows what he's talking about.  And I know NOTHING about any of it.  So if you are gonna disagree with him, please explain why.  Otherwise, people like me, who don't know any better, will believe him.  Right?  Or is that too much for you to read too?

Title: Re: exhaust port
Post by Bubba on 06/09/10 at 10:26:04

Babyhog...+1
just tryin' to learn something here...

Title: Re: exhaust port
Post by Chief Gunner on 06/09/10 at 10:28:57

That's one of the things I like about this site, always different opinions and different ways of doing things. Gives guys like me a lot more info to research and allows me to make an educated decision. Ultimately it's exactly that, a personal decision. If there weren't different opinions we would all be riding the same bike with the same color, and mods wouldn't exist.
Thanks to all for your input.

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 10:31:10

Quiz     Which is turning faster  2 cycle 6000rpm   4 cycle 6000 rpm electric motor 6000 rpm.

Title: Re: exhaust port
Post by babyhog on 06/09/10 at 10:33:40


474C49491312250 wrote:
Quiz     Which is turning faster  2 cycle 6000rpm   4 cycle 6000 rpm electric motor 6000 rpm.


6000 rpm = 6000 rpm.  Revolutions are revolutions.  What difference does the number of cycles make?

Title: Re: exhaust port
Post by ralfyguy on 06/09/10 at 10:37:19

Makes you wonder, why Suzuki even designed the exhaust port that way. The must be a reason for that restriction.

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 10:38:03


4546474A48522B0 wrote:
[quote author=474C49491312250 link=1275542836/45#52 date=1276104670]Quiz     Which is turning faster  2 cycle 6000rpm   4 cycle 6000 rpm electric motor 6000 rpm.


6000 rpm = 6000 rpm.  Revolutions are revolutions.  What difference does the number of cycles make?
[/quote]
Earlytimz thinks it difference.

Title: Re: exhaust port
Post by babyhog on 06/09/10 at 10:47:16


686366663C3D0A0 wrote:
[quote author=4546474A48522B0 link=1275542836/45#53 date=1276104820][quote author=474C49491312250 link=1275542836/45#52 date=1276104670]Quiz     Which is turning faster  2 cycle 6000rpm   4 cycle 6000 rpm electric motor 6000 rpm.


6000 rpm = 6000 rpm.  Revolutions are revolutions.  What difference does the number of cycles make?
[/quote]
Earlytimz thinks it difference. [/quote]

Sorry Bill, you just sound silly now.

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 10:49:09

I thought you read posts,Go back and read Earlys post he says a 2 cycle is turning twice as fast.

Title: Re: exhaust port
Post by BurnPgh on 06/09/10 at 11:07:24

Bill67 - My young fellow 4 cycle motorcycles rev higher than 2 cycle,I've had 3, 2 cycle motorcycles.

Earlytimz - 2 strokers only have 1/2 the revolutions to make a complete cycle. They rev twice as fast.

Ones of you is saying "revs higher" the other "revs faster". In my mind "revs higher" means higher redline and "revs faster" means less time from idle to redline.
Still...if you have a 250 single 4stroke vs a 250 single 2stroke both at 6000rpm the 2 stroke is going to put out more power. It will go through its combustion cycle twice as fast. Right?


Title: Re: exhaust port
Post by earlytimz on 06/09/10 at 11:10:38


747F7A7A2021160 wrote:
I thought you read posts,Go back and read Earlys post he says a 2 cycle is turning twice as fast.


Bill, I said a 2-stroke REVS twice as fast. You shoulda read my post! I'm just saying... You admitted to not reading it...  :-?
I'm not gonna argue with ya, Billy... Agree or not, all I'm saying is do the math... 2-stroke vs. 4-stroke... 2 actions is half of 4 actions, can't argue with that! A 4-stroke fires once while a 2-stroke fires twice in the same amount of revolutions.

Like I stated earlier, it doesn't even matter anyways. This is another topic for another thread. Completely irrelevant to this topic.

Title: Re: exhaust port
Post by Chief Gunner on 06/09/10 at 11:11:12

Baby Hog,
I've included a little info on 2 stroke vs. 4 stroke. I appologize if you already understand the difference. I think what Earlytimes was getting at is that modifying a 4 stokes breathing ability can have noticible gains while a 2 stroke not so much. So when Bill mentioned the 2 stroke motor ......... a 2 cycle fires every stroke, a 4 cylinder every other stroke. Sooo a 2 cycle fires more per RPM than a 4 cycle engine.

How They Work
There is a marked difference in how a 2-cycle and 4-cycle motor operates. A 4-cycle engine works, as you might expect, in four stages. There is the power (down) stroke, the exhaust (up) stroke, the intake (down again) stroke, and the compression (up again) stroke. It takes two full revolutions of the crankshaft to deliver these four strokes. It's the power stroke which sends the piston through each of the three remaining stages.

A 2-cycle engine literally has just two cycles that combine the above duties. The first stroke is the combination power and exhaust stroke and the second combines the compression and intake stroke. Both power and combustion happen as the piston reaches to top of its stroke. At the bottom, the exhaust and intake occur. It takes just a single revolution to generate two strokes and propel the piston through its full cycle.

More Parts = More to Break
Four-cycle engines have a lot more moving parts. They have a crankshaft, camshaft, connecting rod, valves, lifters and of course the piston. A two-cycle engine really has only three major moving parts. This includes the crankshaft, connecting rod and the piston. In small size two cycle engines there are no cams, lifters or valves. As a general rule, less parts equals less potential for failure and easier maintenance. Overall, the 2-cycle engine is typically smaller in displacement and size as compared a 4-cycle which, many times, is almost double the displacement and overall size to achieve the same power. The reason for this is because since the 2-cycle combines two functions in one rotation, it makes the power  twice as quickly as a 4-stroke.




The fact is, 4-cycle only has a few advantages: greater potential torque, higher fuel economy, and better emissions.


Greater Potential Torque = The reason we are playing with it

Title: Re: exhaust port
Post by verslagen1 on 06/09/10 at 11:13:33

So, who can write their name best in the snow?

Do I care? no, ain't got any snow.

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 11:14:18

Burn,Gort is right

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 11:21:59

Chief 4 strokes do not have more torque  than 2 strokes.

Title: Re: exhaust port
Post by BurnPgh on 06/09/10 at 11:30:30


72797C7C2627100 wrote:
Burn,Gort is right


about?

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 11:31:12

Now you guys want to port your exhaust port,You will have a higher speed power band,The jet needle and needle jet on our bikes is made for our powerband,So if you port it you will need a difference jet needle and needle jet.

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 11:32:06


497E79655B6C630B0 wrote:
[quote author=72797C7C2627100 link=1275542836/60#62 date=1276107258]Burn,Gort is right


about?[/quote]
You called me Gort

Title: Re: exhaust port
Post by BurnPgh on 06/09/10 at 11:34:31

oops. Sorry 'bout that.

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 11:39:41

Thats OK he's a good guy.

Title: Re: exhaust port
Post by earlytimz on 06/09/10 at 11:45:58

Hey Bill, that's a lot better than what I called you!!!  ;D

Just kiddin ya, Homie. You ain't a bad guy either... I guess... LoL

Title: Re: exhaust port
Post by Chief Gunner on 06/09/10 at 11:48:33

Bill, I was only highlighting the potential. I would never get into that arguement.
Either motor could come out on top for power, there are so many mods for either one.
Just saying the porting the exhaust on a two stroke is harder to get precise, you would also have to increase the intake pressure due to the short time that the valve are open. Many use blowers to increase how much fuel gets in. With a 4 stroke you have a lot more leeway for error.
I do understand your point about the needle jet increase, either way more out will need more in. Thank you for that.

Title: Re: exhaust port
Post by babyhog on 06/09/10 at 12:10:02

See, now that's alot of information, good or bad, right or wrong.  At least someone could dig more if they wanted/needed.  I shouldn't have jumped in because I really don't care about the specifics.  But if I did, I would want to know which specifics to believe when there are opposing sides.  Bill was saying ET was wrong, but offering no rebuttal.  I look at the un-informed/ignorant/newbie side of posts and if there is bad information, mis-information, whatever... I would hate to see someone do something because they were mis-guided.  That's all.  But I guess if you are gonna mess with something like this, ya best know a little of what you are doin'!!

Title: Re: exhaust port
Post by Serowbot on 06/09/10 at 12:23:48

"Two-strokes produce far more power than four-strokes, but in motocross, peak horsepower is a secondary consideration – it’s not so much about how much power gets to the ground, but in the way in which it gets there. A two-stroke’s power explodes over a short period, whereas the four’s is more linear and results in a far wider power-band. Torque is everything, and four-strokes have it in abundance.

The benefits of having usable power across a wider spectrum are many. For starters, on a four-stroke you don’t have to spend as much time changing gears, and therefore you spend less time with the throttle partially disengaged. The linear power also encourages the rear tyre to grip instead of spin, and its predictability makes it an ideal choice for the lesser-skilled rider."

So,.. it's more about the width of the powerband...
2 strokes make what they make in a narrow rpm band... That's why 4 strokes are considered torqueir...  (torqueir?)... :-?...

Title: Re: exhaust port
Post by earlytimz on 06/09/10 at 12:34:12

Ha Ha... Torqueir... Different strokes for different folks!!

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 12:37:11

I'm not talking about moto cross or race bikes,I'm talking about street bikes.I had a suzuki 550 and 750 2 cycles,They don't have the narrow powerband of a race bike.At 50 mph a Suzuki 750 2 cycle would stay even with a 750 Honda by 60mph it was running away from the Honda,And the Honda was turning more rpm.I would have to say the Suzuki had more torque this was all in high gear roll ons.

Title: Re: exhaust port
Post by LANCER on 06/09/10 at 12:50:55


7D76737329281F0 wrote:
Now you guys want to port your exhaust port,You will have a higher speed power band,The jet needle and needle jet on our bikes is made for our powerband,So if you port it you will need a difference jet needle and needle jet.


not so dude, not with the small amount of change we are talking about here

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 13:06:15


69646B6660773732050 wrote:
[quote author=7D76737329281F0 link=1275542836/60#65 date=1276108272]Now you guys want to port your exhaust port,You will have a higher speed power band,The jet needle and needle jet on our bikes is made for our powerband,So if you port it you will need a difference jet needle and needle jet.


not so dude, not with the small amount of change we are talking about here[/quote]
Since I've been on here you seem to have troubles getting a S40 running you must be doing something wrong.

Title: Re: exhaust port
Post by earlytimz on 06/09/10 at 13:15:17


010A0F0F5554630 wrote:
I'm not talking about moto cross or race bikes,I'm talking about street bikes.I had a suzuki 550 and 750 2 cycles,They don't have the narrow powerband of a race bike.At 50 mph a Suzuki 750 2 cycle would stay even with a 750 Honda by 60mph it was running away from the Honda,And the Honda was turning more rpm.I would have to say the Suzuki had more torque this was all in high gear roll ons.



Considering they are both the same displacement engines, the Suzuki was making more power. That's why in motocross, the 450cc 4-strokes run in the same class as the 250cc 2-strokes. Pound for pound, the 2-strokes make more power... Period.

They both produce torque... That's the force it takes to move an object.

4-stroke torque is normally considered "bottom end" or low end torque. It comes on lower in the rpm's at a steady rate, dropping off after a certain level. It is more manageable and predictable.

2-stroke torque is produced well up into the rpm's also known as the power band. It comes on quickly but also drops off at a certain level. Adding multiple cylinders will smooth it out a lot, but the 4-stroke is ultimately smoother & easier to ride.

There's a lot more involved than just 2 or 4 cycles. You have stroke length, bore size, compression ratio, multiple & single cylinders, etc...

Title: Re: exhaust port
Post by bill67 on 06/09/10 at 13:17:27

Good information go tell your kid ::)btw what was the last 2 cycle street bike you had

Title: Re: exhaust port
Post by earlytimz on 06/09/10 at 14:06:39

Go tell my kid??

All my 2-strokes were offroad only. Never had a 2-stroke street bike. I had a friend who kept alive a '75 -(I think) kawasaki 750, 3 cylinder, 2-stroke. That thing was a BEAST! You could definitely tell it was a 2-stroke.

What's your point?

Title: Re: exhaust port
Post by LANCER on 06/09/10 at 17:09:30


5A5154540E0F380 wrote:
[quote author=69646B6660773732050 link=1275542836/75#75 date=1276113055][quote author=7D76737329281F0 link=1275542836/60#65 date=1276108272]Now you guys want to port your exhaust port,You will have a higher speed power band,The jet needle and needle jet on our bikes is made for our powerband,So if you port it you will need a difference jet needle and needle jet.


not so dude, not with the small amount of change we are talking about here[/quote]
Since I've been on here you seem to have troubles getting a S40 running you must be doing something wrong.[/quote]

hmmmmm,  what's up man ?

Title: Re: exhaust port
Post by Serowbot on 06/09/10 at 17:20:26


333E313C3A2D6D685F0 wrote:
[quote author=5A5154540E0F380 link=1275542836/75#76 date=1276113975][quote author=69646B6660773732050 link=1275542836/75#75 date=1276113055][quote author=7D76737329281F0 link=1275542836/60#65 date=1276108272]Now you guys want to port your exhaust port,You will have a higher speed power band,The jet needle and needle jet on our bikes is made for our powerband,So if you port it you will need a difference jet needle and needle jet.


not so dude, not with the small amount of change we are talking about here[/quote]
Since I've been on here you seem to have troubles getting a S40 running you must be doing something wrong.[/quote]

hmmmmm,  what's up man ?[/quote]
Shorts are a little snug today... :-?...

Title: Re: exhaust port
Post by LANCER on 06/09/10 at 19:29:49


392F38253D28253E4A0 wrote:
[quote author=333E313C3A2D6D685F0 link=1275542836/75#80 date=1276128570][quote author=5A5154540E0F380 link=1275542836/75#76 date=1276113975][quote author=69646B6660773732050 link=1275542836/75#75 date=1276113055][quote author=7D76737329281F0 link=1275542836/60#65 date=1276108272]Now you guys want to port your exhaust port,You will have a higher speed power band,The jet needle and needle jet on our bikes is made for our powerband,So if you port it you will need a difference jet needle and needle jet.


not so dude, not with the small amount of change we are talking about here[/quote]
Since I've been on here you seem to have troubles getting a S40 running you must be doing something wrong.[/quote]

hmmmmm,  what's up man ?[/quote]
Shorts are a little snug today... :-?...[/quote]


;D

Title: Re: exhaust port
Post by Oldfeller on 06/10/10 at 02:18:05

I think there is a bit of general "disgruntle" running about which occurred over in The Cafe and is now leaking out all over the place.

Due to "de general mood" it probably isn't smart to start heavy discussions about technical stuff -- or at least be sensitive that some of the folks are a bit tense about other stuff.

I rode two and four stroke bikes -- back in the 70's - 80's two strokes owned light and powerful and heavy and mighty because they made twice as many power strokes (mebbe technically "weaker" for the cc  and certainly more polluting power strokes, but a hell of lot of them).


=================================


However, I am really gonna stir this discussion up when I remind everyone that 4 stroke technology caught up when race bikes were all forced to be 4 stroke engines and 4 stroke development continued apace in both cars and bikes to new heights and 2 strokes became functionally extinct.

Let's talk about the KING, the Kawasaki H-2 750cc triple.  Unheard of hp and torque for its day.   Scarey megabike .... whhoooo  I had to grow up some before I could dare buy and ride one (and I did).

Fast forward 30 years .....

Let's talk about the old lame Suzuki SV650 and the Gladus, it's newish girly cute version.   Nice beginners bike for the ladies, you can learn on it and keep it for several years before moving on to a bigger crotch rocket or a large cruiser type.  The very least of the real crotch rocket crowd, fer shure.


;D   ;D   ;D    now for the fun part


Please consider, kind reader, that the operating specifications, hp and top ends of the mighty H2 (KING of the two strokes) and the SV650/Gladus beginner bike are closely the SAME.

Ok, let the discussions begin .....   for sake of sanity if you are talking drag strip conditions say so and quote your quarter mile times for both bikes, etc.

If you are talking street riding conditions say so ......  etc.

And if you are going to talk about tweaked and ported, etc please do the same to the other bike to be fair.



Title: Re: exhaust port
Post by bill67 on 06/10/10 at 04:07:27

Motorcycles quit making 2 cycles,But snowmobiles didn't.With rotary valves and reed valves which gave the 2 cycles lower end torque without hurting the higher end power.650 cc motors were putting out over 100 hp at only 8000 rpm,That was 20 years ago.Bottom line 2 cycle much more torque than 4 cycle.How would you like a S40 650 2 cycle putting out 100 hp.And it would be maybe 40 pounds lighter,And don't forget the good sound you get from a 2 cycle ;D

Title: Re: exhaust port
Post by LANCER on 06/10/10 at 04:59:02

My first bike was a Suzuki 150 twin 2-stroke.  It was a great little bike and all my efforts at hard riding it just kept on running.
If I had the $$ I would have bought the Kaw 750 3 cyl; took a test drive on one and had a heck of a ride.  Back then you could just ride up and test drive most any bike   :)

Anyway, I like the simplicity of a 2 stroke and the power potential; have nothing against the 2 stroke at all.  I just happen to like the sound and power characteristics of a large 4 stroke single; and I like to tinker with them.  My skills and tools are limited so I stick with the simpler modifications and have a professional do other stuff if needed.

A few of the more recent bike builds that have been posted on this site are just amazing.  I wish I could do that type of work, but I know my limits.

Title: Re: exhaust port
Post by Oldfeller on 06/10/10 at 05:01:09

Here's some fuel for that fire -- two strokes hit their peak development in snowmobiles, outboard motors and jet ski applications (mainly because two stroke pollution restrictions didn't hit those areas until later on).

Four stroke engines now rule those areas also -- and I was amazed to go into my fishing store and find out 1) how small and powerful 4 stroke outboard engines had become and 2) how durn expensive even a trolling motor was now-a-days.

Sorry Bill, we are both 2 stroke dinosaurs now.  Even Klotz has to sell 4 stroke oil now to stay in business because there ain't no world for two stroke engines anywhere except maybe for chain saws and little bitty air plane engines (and 4 stroke engines are showing up there now too in the larger engine sizes).

EPA drove it to get it started, but engineering development will finish it.  

Count the power strokes to see how it is all developing.  An H2 Kawasaki triple red lined at 6,800 rpm and counted out 3,400 power strokes in a minute on each cylinder, or a total of 10,200 power pulses per minute.  An SV650 red lines at 11,500 rpm and counts out 2,875 more efficient power strokes per cylinder, or a total of 5,750 power pulses per minute which is enough to give it H-2 parity at 100 fewer ccs displacement.   4 stroke pulses are simply more powerful than two stroke pulses.
(sorry Bill, they are)


But an SV650 is an older twin cylinder design now-a-days.

Consider a totally modern 599cc modern 4 stroke design which has 4 cylinders and turns up to 16,500 rpm at red line.  The math is easy anyway, 16,500 power strokes in a minute as the little beasties are even pulse tuned now to fire one cylinder per crank revolution to keep the rear tire being evenly driven at all times (racing traction being the only limiter that people even pay attention to any more since hp went well over 100 hp a while ago and they started having to tune for traction rather than peak HP)   Read your bike magazines, computerized traction control is all the rage as they can't ever use the hp that is already there without pulling big power wheelies at 150 mph.

Bill, that's well over your 100 hp magic number, already done been here for a while now readily available at any BMW, HONDA, Kawasaki or Yammaha dealership at 0% financing right now as we speak.   At less cc to boot, just to rub a little salt into the poor old two stroke's wounds.

Two strokes are dead for a reason -- they are no longer competitive.   And EPA loves them not, so they will stay dead going out into the future.

Even Klotz thinks so ....   they gotta try to make that transition into being "the 4 stroke super oil" if they can.    Maybe they can, but it's up to what Verslagen finds out when he puts it in his high performance skeeter fogger later on this summer as to whether Klotz is the Savage Super Oil or not.

Title: Re: exhaust port
Post by bill67 on 06/10/10 at 05:12:21

Two strokes are dead for one reason EPA.I like 4 strokes better,But don't go back to 1970 when you talk of 2 stoke engines,There have been big improvements on 2 strokes since 1970.Race snowmobiles are putting out over 200 hp.But we need only to talk street bikes because thats what we ride.

Title: Re: exhaust port
Post by Oldfeller on 06/10/10 at 05:46:44


Good point about them race tuned 2 stroke snowmobiles at 200 hp.  

What is the displacement of those puppies so I can select me an equivalent displacement 4 stroke race bike?  I gots me so many to pick from, some with turbos and such at over 500 hp but I gots to limit myself to getting as close to equivalent cylinders and displacement and such (or less) just to make the salt smart more.

Or, I could just wait a bit and let someone put together a turbocharged or blown race tuned Yamaha snowmobile .....

http://www.snowmobile.com/manufacturers/yamaha/2010-yamaha-nytro-rtx-se-review-1015.html


;D   ;D   ;D


I can't believe them folks complaining about the 4 stroke pulling too many power wheelies in the turns "lifting the skis" too much !!    They need some of that motorcycle style computerized traction control technology on them modern snow sickles.

Title: Re: exhaust port
Post by bill67 on 06/10/10 at 05:51:28

That yamaha is a trail snowmobile not a race snowmobile.That one for the wife to ride.

Title: Re: exhaust port
Post by Oldfeller on 06/10/10 at 06:00:41


Give the wifey that old poky old slow stock 150 hp 4 stroke Yamaha sled and let her deal with the power wheelies, huh?  

Title: Re: exhaust port
Post by earlytimz on 06/10/10 at 06:04:09

From exhaust porting to your wife's snowmobile... Here at the Rubber Side Down Showdown, we have it all!!

BTW, some of the new 2-stroke outboards claim to be just as clean and efficient as the 4 strokes & still making more power.

I've got a 4-stroke weedeater now and IT SUCKS! It's heavy, less power even with a bigger engine & it doesn't have that 2-stroke smell that gets me fired up on a Saturday morning. Maybe I'll port the head on that sucker... What do u think Bill??

Title: Re: exhaust port
Post by bill67 on 06/10/10 at 06:10:26


2C0F0705060F0F0611630 wrote:

Give the wifey that old poky old slow stock 150 hp 4 stroke Yamaha sled and let her deal with the power wheelies, huh?  

Oldfellow its called ski lift

Title: Re: exhaust port
Post by Oldfeller on 06/10/10 at 06:19:39


'scuse me, I confess I am "snow ignorant" pretty much.  

To me that's the dingus that gets you to the top of the bunny slope so you can fall down a lot on the way to the bottom.

:D    ;D   :D    ;D

And yes we do enjoy our windy meandering little discussions around here quite a bit.

Johnson/Evenrude/Mecury/Mariner ARE trying to come up with a decent fuel economy and pollution control out of a two stroke engine.   They have made improvements but are not EPA compliant but for another few more years.  They are frantically buying time while they work on their new stuff.

They certainly can see the handwriting on the wall though --  and guess who is busy developing a full line of four stroke line of outboards to try to compete with Honda and Suzuki outboards .....

http://www.outboardrepairs.com/4_stroke_outboards/#johnson_4_stroke_outboards

http://www.marineroutboards.co.uk/products.php?range_id=1&section_id=NULL

Ditto for all the rest of the "same name" American outboard companies,  they will have different cowlings but very similar 4 stroke engines living underneath it.

Can't speak to weedeaters and chain saws -- I think your package size dictates a very light two stroke single cylinder engine pretty much.  

Research shows that Honda, Ryobi, Stehl and others all have commercial 4 stroke weed eaters out there that folks don't like because of the extra weight -- chainsaws and weedeaters really have packaging/size limitations that may keep them 2 stroke even if EPA doesn't care for it.

Now, ask yourself this -- if chainsaws and weedeaters get an exemption from EPA to stay two stroke why can't the Chinese make a cheap 50 hp RD400 rip-off copy and bring 'er on into the USA ????

Like I said, some things simply have package/size limitations and the RD 400 was as big as it could possibly be and still be a neat/nifty pocket rocket like it was !!!!

Title: Re: exhaust port
Post by dasch on 06/10/10 at 10:52:44

Holy crap, this discussion went to $hit quick! Wanna port the exhaust - go ahead! I will too, most likely! The topic is about porting the head. You don't think it's a good idea - fine. Don't read it. Don't post. Don't care.
No offence, but I really get tired of "I never did it, but you shouldn't either"!
What I want to hear is - "I did it, and here's what happened"
Guys, please...

Title: Re: exhaust port
Post by jarrod on 06/10/10 at 12:19:56

Finally, somebody said it. ;D

Title: Re: exhaust port
Post by Bubba on 06/10/10 at 12:32:09

okay, back on topic...if I port the exhaust to match the header (over the winter probably) will that produce the same effect as running a more open pipe AND will that then make the bike run leaner?
I'm a mile high have a 2/3 spacer, pretty open pipe K&N drop in air filter, 150 main and 52.5 w/bleed holes, air screw out 2 turns.
Answers from those of you that have done it please
thx

Title: Re: exhaust port
Post by Serowbot on 06/10/10 at 12:42:22

only if you're running an open pipe...

Porting will just allow a less restrictive pipe to flow at  it's full potential...  
Probably won't do anything with a stock muffler...

Title: Re: exhaust port
Post by Bubba on 06/10/10 at 12:48:29

pipe is like this...

http://i823.photobucket.com/albums/zz155/onelunger/IMG00224.jpg

Title: Re: exhaust port
Post by earlytimz on 06/10/10 at 13:17:17

That pipe is perfect...
You may run a little leaner after the porting, it's hard to say until you do it. Be prepared to check it but If I had to take a guess I'd say you will be fine, especially at your elevation. We're not talking about major surgery here, just letting your lung exhale a little easier. Your engine will rev up a little faster & it will be a little more efficient. There's potential for more power, because your getting more bang out of the work the engine is already doing.

Title: Re: exhaust port
Post by Bubba on 06/10/10 at 13:32:15

Thanks earlytimz, I gotta tell ya, this pipe was the first thing I installed and I love the sound of it. Initially I thought it was too loud but it definately grows on you. Nice low rumble at idle, clean sound when cruising and flat out loud when I make it backfire so I get noticed by all the folks yakkin' on their cell phones when they should be drivin'...

Title: Re: exhaust port
Post by ralfyguy on 06/10/10 at 15:36:48

What pipe is that?

Title: Re: exhaust port
Post by earlytimz on 06/10/10 at 16:15:30

My muffler looks a lot like that one inside, but it has a turn-out at the end. I was worried about how it would sound since it was an ebay special I got pretty cheap. I'm happy with it though. Not painfully loud until I really flog on it... Mine is a MAC, basically a screaming eagle knock-off for a bagger.

Title: Re: exhaust port
Post by james may on 06/10/10 at 17:45:37


Quote:
Makes you wonder, why Suzuki even designed the exhaust port that way. The must be a reason for that restriction.


most automotive companies don't port thier heads.. the odd shapes inside and around cast cylinder heads are mostly due to the casting process and how they have to make the molds.  Also some of those odd shapes are there for extra structural support to prevent cracking.  

In order to get smooth intake and exhaust ports it would need machining which is an extra expencive step in production.. so cost is the main reason why ports are not polished and smooth..

You do lose a little low end power when you increase exhaust flow.. if you equally increase intake flow you should keep your low end power though.. the reason is compression.. at low RPMs there isn't enough momentum in the air charge to pull it in especially with a longer intake duration(as seen in performance cams)..  when you have a restricted exhaust some of the gas is not eliminated on the exhaust stroke and stays in the cylinder.. but that's ok because you can't get the air into the cylinder fast enough anyways.. but the extra gas contributes to higher compression which gives you more low end power.

at higher RPMs the air actually forces itself in by momentum even after the piston is done sucking it in.. This allows you to get more air/fuel and more power.  

the power you get in your engine is a direct result of the pressure caused by fuel combustion.  In a case where the air/fuel is less than optimal as in low rpms having extra gas in there increases the pressure also increasing power..

Porting and polishing are usually just to get that last bit of power you can't get any other way.. It's also free if you do it yourself, but very labor intensive(expensive if you have someone else do it).. a new exhaust or a free flowing air filter will give more power, but if you've already done all of the above you might get a few extra pony's from it..

almost everything to improve performance is done to increase air(oxygen) in the combustion chamber.. then as a secondary thought of course you can easily increase fuel to match the air..


Title: Re: exhaust port
Post by LANCER on 06/10/10 at 18:27:23

yep, there's nothing quite like a single cylinder air pump to make for a fun day of wind in your face !
Throw in some drops of fuel along the way, lite the fire and away we go ! !  ;D

Title: Re: exhaust port
Post by omahasavage on 06/10/10 at 19:20:04

ahw, i was enjoying watching the thingy fight we had going.  Why did we get back on topic? :D


edit:  i spelled c.o.c.k and it put "thingy"  awesome!  that seriously made me lol

Title: Re: exhaust port
Post by dasch on 06/10/10 at 19:22:33

:)

Title: Re: exhaust port
Post by Bubba on 06/10/10 at 19:37:51

ralfyguy, I bought it on ebay last year. It was from a place that sells closeout/discontinued stuff. I think I paid something like 40 bucks + shipping for 2 of them...BRAND NEW and very shiny. They were called DynoPowers or something like that.

Title: Re: exhaust port
Post by bill67 on 06/10/10 at 19:49:02


14150E051214191005600 wrote:

Quote:
Makes you wonder, why Suzuki even designed the exhaust port that way. The must be a reason for that restriction.


most automotive companies don't port thier heads.. the odd shapes inside and around cast cylinder heads are mostly due to the casting process and how they have to make the molds.  Also some of those odd shapes are there for extra structural support to prevent cracking.  

In order to get smooth intake and exhaust ports it would need machining which is an extra expencive step in production.. so cost is the main reason why ports are not polished and smooth..

You do lose a little low end power when you increase exhaust flow.. if you equally increase intake flow you should keep your low end power though.. the reason is compression.. at low RPMs there isn't enough momentum in the air charge to pull it in especially with a longer intake duration(as seen in performance cams)..  when you have a restricted exhaust some of the gas is not eliminated on the exhaust stroke and stays in the cylinder.. but that's ok because you can't get the air into the cylinder fast enough anyways.. but the extra gas contributes to higher compression which gives you more low end power.

at higher RPMs the air actually forces itself in by momentum even after the piston is done sucking it in.. This allows you to get more air/fuel and more power.  

the power you get in your engine is a direct result of the pressure caused by fuel combustion.  In a case where the air/fuel is less than optimal as in low rpms having extra gas in there increases the pressure also increasing power..

Porting and polishing are usually just to get that last bit of power you can't get any other way.. It's also free if you do it yourself, but very labor intensive(expensive if you have someone else do it).. a new exhaust or a free flowing air filter will give more power, but if you've already done all of the above you might get a few extra pony's from it..

almost everything to improve performance is done to increase air(oxygen) in the combustion chamber.. then as a secondary thought of course you can easily increase fuel to match the air..

That would be nice if that worked but it doesn't,You lose low end torque,If it worked you would only need one size engine you just put on big carb big ports,big exhaust and you have the power you wanted,Being you lose low end power you have to go to a bigger engine to get more low and high end power.

Title: Re: exhaust port
Post by omahasavage on 06/10/10 at 20:15:02

that's the spirit!

Title: Re: exhaust port
Post by earlytimz on 06/10/10 at 20:29:59


36372C2730363B3227420 wrote:

Quote:
Makes you wonder, why Suzuki even designed the exhaust port that way. The must be a reason for that restriction.


most automotive companies don't port thier heads.. the odd shapes inside and around cast cylinder heads are mostly due to the casting process and how they have to make the molds.  Also some of those odd shapes are there for extra structural support to prevent cracking.  

In order to get smooth intake and exhaust ports it would need machining which is an extra expencive step in production.. so cost is the main reason why ports are not polished and smooth..

You do lose a little low end power when you increase exhaust flow.. if you equally increase intake flow you should keep your low end power though.. the reason is compression.. at low RPMs there isn't enough momentum in the air charge to pull it in especially with a longer intake duration(as seen in performance cams)..  when you have a restricted exhaust some of the gas is not eliminated on the exhaust stroke and stays in the cylinder.. but that's ok because you can't get the air into the cylinder fast enough anyways.. but the extra gas contributes to higher compression which gives you more low end power.

at higher RPMs the air actually forces itself in by momentum even after the piston is done sucking it in.. This allows you to get more air/fuel and more power.  

the power you get in your engine is a direct result of the pressure caused by fuel combustion.  In a case where the air/fuel is less than optimal as in low rpms having extra gas in there increases the pressure also increasing power..

Porting and polishing are usually just to get that last bit of power you can't get any other way.. It's also free if you do it yourself, but very labor intensive(expensive if you have someone else do it).. a new exhaust or a free flowing air filter will give more power, but if you've already done all of the above you might get a few extra pony's from it..

almost everything to improve performance is done to increase air(oxygen) in the combustion chamber.. then as a secondary thought of course you can easily increase fuel to match the air..


Very good info!
I'd like to add something specific to the savage head...
My personal opinion is the exhaust port is purposely restricted to match the lack of fuel allowed into the engine by the small jets. This of course is Suzuki's solution to the strict emissions standards. They could have cast these heads with better ports, but then they would need to feed the engine more fuel to match, throwing off the emissions.
All we're doing by porting the exhaust is better matching it to the intake. Most folks have already upgraded the fuel supply. You're correct that this is kinda the last resort for performance, or as I like to think, it's the missing link!

Title: Re: exhaust port
Post by earlytimz on 06/10/10 at 20:30:55


7B79757C75677562757371140 wrote:
that's the spirit!


Hey man, quit thingy ing around!

Title: Re: exhaust port
Post by omahasavage on 06/10/10 at 20:56:21

okay, gotta test this out

thingy

thingy

member

thingy

crappity smackstick

manshaft

dipstick

ladykiller

dong

wang

peepee

dinky

tubesteak

slobersickle

peter

porker

one eyed monster

Willie



sorry, i've had a bit to drink tonight.  I make my own beer and well I had to try out a few for quality control purposes, you know.   ;)


edit:  so it's only d.i.c.k, c.o.c.k and p.e.n.i.s that gets edited.  of course f.u.c.k.s.t.i.c.k got changed to "crappity smackstick"  that's very interesting.  which makes me wonder if crappity smack gets changed to "crappity smack"  or what.  yup, f.u.c.k gets changed to "crappity smack"   :)

Title: Re: exhaust port
Post by earlytimz on 06/10/10 at 21:06:39

LMFAO!! Slobersickle??? You're killin me!!

BTW, I'm a home-brewer too. Haven't made a batch in over a year, but I really enjoy it. I think you may have motivated me to start one this weekend...

Title: Re: exhaust port
Post by omahasavage on 06/10/10 at 21:48:17

so the thingy comments made you want to make beer?

Title: Re: exhaust port
Post by Oldfeller on 06/11/10 at 03:33:57


Yep, threads tend to meander around here .....

Title: Re: exhaust port
Post by dasch on 06/11/10 at 05:08:06

>:(

Title: Re: exhaust port
Post by earlytimz on 06/11/10 at 05:40:56

C'mon dasch, my Bosnian brother... Cheer up, It's FRIDAY!!!

Title: Re: exhaust port
Post by dasch on 06/11/10 at 08:00:43

ok, just for you man:  ;D

Title: Re: exhaust port
Post by Serowbot on 06/11/10 at 10:20:11


585A565F56445641565052370 wrote:
ahw, i was enjoying watching the thingy fight we had going.  Why did we get back on topic? :D


edit:  i spelled c.o.c.k and it put "thingy"  awesome!  that seriously made me lol


Years back,...  the auto site-censor would not allow the word "petcock"...
Baffled newbies were always asking,... "What's a pethingy, and where can I find it?"....
"How do I check my pethingy?",...


PS,..
Omaha,.. You're short, and you ride sidesaddle...
Just so you don't feel left out...
Welcome to the club...;D...



Title: Re: exhaust port
Post by james may on 06/11/10 at 21:11:24


Quote:
That would be nice if that worked but it doesn't,You lose low end torque,If it worked you would only need one size engine you just put on big carb big ports,big exhaust and you have the power you wanted,Being you lose low end power you have to go to a bigger engine to get more low and high end power.


If ya actually read the post you'd see that it was just annoying me that nobody explained why any of this happened just stating it did... I stated that because exhaust gasses are expelled more completely you lose power in the lower RPM band..

Title: Re: exhaust port
Post by verslagen1 on 06/11/10 at 22:19:12


17160D0611171A1306630 wrote:

Quote:
That would be nice if that worked but it doesn't,You lose low end torque,If it worked you would only need one size engine you just put on big carb big ports,big exhaust and you have the power you wanted,Being you lose low end power you have to go to a bigger engine to get more low and high end power.


If ya actually read the post you'd see that it was just annoying me that nobody explained why any of this happened just stating it did... I stated that because exhaust gasses are expelled more completely you lose power in the lower RPM band..

I think this was talked a little about when there was a discussion about exhaust pipe length and size.
I'm gonna use 2stroke as an example cause it's the extreme...
When the piston opens the exhaust port, the hot gases rush out.  This flow creates a momentum and when the intake opens it pulls in a fresh charge.  You can get a lot of unburned gas in the tail pipe if it wasn't tuned.  Tuning causes the exhaust pressure wave to bounce back and push the unburned gases back into the chamber before the piston closes the port.  Now this bounce happens best at certain rpm's and not as well at others.
Now this does happen with 4strokes but in different ways.  If the pressure wave bounces on the exhaust port just as it opens, it's going to slow down the exhaust.  And also with the intake.  So that little ridge right where the header hooks up is called a torque cone (oh I picked that up from someone here, don't remember who)  And it works to bounce the pressure wave back before it hits the exhaust port.  I think the reduction a little bit into the header works at this too.  causing the pressure wave to slow down before impact.

Now all this has to be tuned to work over a broad range of rpm's.

Title: Re: exhaust port
Post by LANCER on 06/12/10 at 05:20:57

There's nothing like a little hot exhaust talk first thing in the morning to get ya up and running !   :)

Title: Re: exhaust port
Post by MeeLee on 01/28/16 at 19:08:17

Now, I know this is a 5 year old thread, and resuscitating it might bring up old smells like my 5 year old dead cat buried in my back yard...
I was really interested in the exhaust port mod, and had to skip some posts concerning 2 strokes vs 4, and other people's ex- wives and what not...

My question would be,
Would it be possible, to open up the exhaust port, gain top speed hp, and to compensate, try to increase compression in an easy, cheap and quick way?

I remember back in the day, guys would take a gasket out of the cylinder, and replace it with a paper thin one, and it would increase compression.
This, to gain low end torque.

I always thought that by freeing the exhaust system up from back pressure, that the engine somewhat was running leaner, and needed a larger pilot jet?
But the posts before, mentioned it being loss of compression.

Is there any way to improve compression through a "tuned" air intake?

Title: Re: exhaust port
Post by Kris01 on 01/28/16 at 19:52:24


1A32321B3232570 wrote:
Would it be possible, to open up the exhaust port, gain top speed hp, and to compensate, try to increase compression in an easy, cheap and quick way?

Why all the questions about top speed? This ain't the bike to set land speed records. But, yes, opening the exhaust port and increasing compression will help. It will neither be cheap nor easy. Wiseco offers a larger piston to increase engine size. The real benefit is higher compression.



1A32321B3232570 wrote:
I remember back in the day, guys would take a gasket out of the cylinder, and replace it with a paper thin one, and it would increase compression.
This, to gain low end torque.

Certainly possible but you need to watch valve clearances to the piston.



1A32321B3232570 wrote:
I always thought that by freeing the exhaust system up from back pressure, that the engine somewhat was running leaner, and needed a larger pilot jet?
But the posts before, mentioned it being loss of compression.

Compression won't change because you opened the exhaust. I dunno why but you will need larger jets if you open up the exhaust.



1A32321B3232570 wrote:
Is there any way to improve compression through a "tuned" air intake?

That won't affect compression.


BTW, when you say "compression" or you really meaning "cylinder pressure"?

Title: Re: exhaust port
Post by MeeLee on 01/28/16 at 23:49:33


78415A400302330 wrote:
[quote author=1A32321B3232570 link=1275542836/120#123 date=1454036897]Would it be possible, to open up the exhaust port, gain top speed hp, and to compensate, try to increase compression in an easy, cheap and quick way?

Why all the questions about top speed? This ain't the bike to set land speed records. But, yes, opening the exhaust port and increasing compression will help. It will neither be cheap nor easy. Wiseco offers a larger piston to increase engine size. The real benefit is higher compression.



1A32321B3232570 wrote:
I remember back in the day, guys would take a gasket out of the cylinder, and replace it with a paper thin one, and it would increase compression.
This, to gain low end torque.

Certainly possible but you need to watch valve clearances to the piston.



1A32321B3232570 wrote:
I always thought that by freeing the exhaust system up from back pressure, that the engine somewhat was running leaner, and needed a larger pilot jet?
But the posts before, mentioned it being loss of compression.

Compression won't change because you opened the exhaust. I dunno why but you will need larger jets if you open up the exhaust.



1A32321B3232570 wrote:
Is there any way to improve compression through a "tuned" air intake?

That won't affect compression.


BTW, when you say "compression" or you really meaning "cylinder pressure"?[/quote]



You realize that what you're saying is the opposite of what people have been saying in this thread?
That freeing the exhaust port, results in lower compression. You say this isn't so; I'd be interested in hearing why not?

The valve clearances usually are ok, even when removing a cylinder gasket (which, without ever seeing one of an S40, I would guess be like 1 to 2 mm in thickness).
What's worse is pinging due to a too high compression ratio.

Just like a tuned exhaust, there is a tuned in. The air that gets drawn in, gets drawn in in pulses. With the right tune, the air at the valves will be under pressure, and more air can enter in than a non tuned air input, thus increasing the compression ratio, by allowing more fresh air in.
Not sure if this is the case with the S40 though...

Title: Re: exhaust port
Post by Dave on 01/29/16 at 03:57:43


587070597070150 wrote:
You realize that what you're saying is the opposite of what people have been saying in this thread?
That freeing the exhaust port, results in lower compression. You say this isn't so; I'd be interested in hearing why not?

The valve clearances usually are ok, even when removing a cylinder gasket (which, without ever seeing one of an S40, I would guess be like 1 to 2 mm in thickness).
What's worse is pinging due to a too high compression ratio.

Just like a tuned exhaust, there is a tuned in. The air that gets drawn in, gets drawn in in pulses. With the right tune, the air at the valves will be under pressure, and more air can enter in than a non tuned air input, thus increasing the compression ratio, by allowing more fresh air in.
Not sure if this is the case with the S40 though...


You seem to be focused on the exhaust port.  With the stock cam and piston and muffler...there is very little to be gained by fussing with the ring in the exhaust port.  It is not a big restriction to the engine in stock form...as the cam is very mild, the compression is low, and there just isn't a lot of HP looking for a way to get out of the engine.  The big restriction in getting more top speed and engine rpm....is the piston speed.  The Savage engine has a pretty long stroke - and the piston is just moving too fast to make any additional power once you get the engine spinning really fast.  That is one of the reasons the HP numbers drop off when the engine rpm passes 5,000 rpm.

When you lower the head on the Savage to get a higher compression with the stock piston - you affect the length of the cam chain - and you also retard the timing on the cam chain.....and the late timing will get worse as the chain stretches/wears.  Whatever distance you lower the head....the cam chain length is affected by double that amount.  The Savage engine uses up the available cam chain life too soon already, and lowering the head will only make that worse.  The absolute best way to increase compression, and torque on this engine, is to install a Wiseco piston.  

When modifying this engine, the best approach is to increase the power that is made below 5,000 rpm....and gear the bike so that it operates in that range.  Big singles are famous for low rpm torque...not for making HP (or for being freeway flyers).


Title: Re: exhaust port
Post by Art Webb on 01/29/16 at 07:40:29

I remember when the first Honda Interceptors came out
a guy who had just bought one pulled up to my buddy and I at a red light, gave us 'the look' and gunned his engine a couple times
My buddy was on a Norton, and smoked the guy off the line, holding the lead until the 1-2 upshift, where the Interceptor, having hit it's sweet spot in 1st, blew by him
the guy couldn't believe That Norton had walked him off the line, he just did not get that a big single makes power differently than an I4
but that off topic
doing the exhaust port on this engine without adding compression is like doing a high end valve job on a late 70s smog mobile V8 without adding compression, it's doing 1/2 the job, but it won't net 1/8 the performance

Title: Re: exhaust port
Post by Kris01 on 01/29/16 at 11:29:45

I'm not going against what's been said already. If you open the exhaust port you are allowing the exhaust gases to exit faster. They don't build up behind the port as easy. This will effectively lower the cylinder pressure (not compression -- I'm picky about terminology.). There's absolutely nothing you can do to change the compression ratio without changing the "squish area" above the piston.

Once the piston is moving fast enough and bringing in more air faster than the newly opened up exhaust port can expel the exhaust gas you start making up the loss in cylinder pressure. That's why opening the exhaust up moves your power higher in RPMs. The engine has to rev higher in order to make the same cylinder pressure.

Title: Re: exhaust port
Post by MeeLee on 01/29/16 at 14:13:49


142D362C6F6E5F0 wrote:
I'm not going against what's been said already. If you open the exhaust port you are allowing the exhaust gases to exit faster. They don't build up behind the port as easy. This will effectively lower the cylinder pressure (not compression -- I'm picky about terminology.). There's absolutely nothing you can do to change the compression ratio without changing the "squish area" above the piston.

Once the piston is moving fast enough and bringing in more air faster than the newly opened up exhaust port can expel the exhaust gas you start making up the loss in cylinder pressure. That's why opening the exhaust up moves your power higher in RPMs. The engine has to rev higher in order to make the same cylinder pressure.


Terminology or not, if there are still pressured gasses in the cylinder before the intake valve opens up, you end up with more gas in the cylinder on the compression stroke than if the cylinder would completely empty out of gas.
Cold air fuel mixes with more hot gasses, causing the cold gasses to expand,
Thus, increasing compression as well.
Well, technicallyyou're right in that the compression ratio hasn't changed, since the stroke and chamber remain the same size,
But pressure on the compression stroke has; so if you had a pressure gauge, it would show higher compression.

Opening the exhaust port will exit more hot gasses, thus allowing more cold gas to enter in the cylinder, and less expansion of the cold gas through mixing with hot gasses, essentially lowering compression due to lower air temperature, and less gas in the cylinder.
There! I think I said it twice in one sentence!  :D

This results in higher efficiency, as the cold gas only starts expanding once it ignites, rather than as soon as it enters the chamber.
This also should result in lower vibrations, as there is less resistance at the exhaust, and less resistance at the compression stroke, again causing higher efficiency.

But that'd be my take on it all...

Title: Re: exhaust port
Post by Kris01 on 01/29/16 at 18:56:23

I don't think that would cut down on vibration. This bike vibrates mostly due to the long stroke/long conrod/single cylinder design. There's a lot of rotating mass in the bottom end that's not offset by another piston moving in the opposite direction.  ;)

Title: Re: exhaust port
Post by Kris01 on 01/29/16 at 19:14:07

I think your idea is a little off. When the intake valves open, the exhaust valves are already open. It helps to pull in a fresh intake charge. It's called scavenging. If there are any residual exhaust gases left (and there are!), it would be minimal and not likely to cause any appreciable heating of the intake charge. Besides, we only have 8:1 compression. That's not really conducive to burning the air/fuel mixture very efficiently. At 8:1, cylinder pressure and temperature shouldn't really get very high.

BTW, please don't say compression when you mean cylinder pressure. It's not the same thing.  ;)

(I don't mean that to sound condescending.  :))

Title: Re: exhaust port
Post by cheapnewb24 on 01/29/16 at 19:14:16

Does increasing compression ratio help low end torque more or high end torque. It would increase the chances of knocking at high load/low rpm.

Do pressure spikes from detonation end at higher rpms, or are they present no matter what in the event of knock-prone conditions?

Title: Re: exhaust port
Post by Kris01 on 01/29/16 at 19:18:43

Pre-detonation can happen at any rpm. You just can't hear it when you're screaming down the road at WOT.

Higher comp ratios should increase torque at every rpm. It promotes a more complete burn of the air/fuel mixture plus, by reason of being compressed more, it explodes with a bigger bang making more power.

Title: Re: exhaust port
Post by MeeLee on 01/29/16 at 22:39:43

For that reason it's important to start researching about installing a newer piston (with higher compression) and camshaft.
At 8:1 there's nothing like pre-detonation.
That usually doesn't happen until 10.5:1 or 11:1.
If it does ping, you can always go mid-grade, or premium.
Premium with Shell or BP gives you an additional 5 to 10% on performance gain, because the gasoline is mixed with some other high chemical energy fluids (some say BP and Shell use nitrogen based chemicals in their premium blends).

How much for parts and labor to get a new camshaft and higher compression piston installed?
I presume the newer piston might be also a little lighter in weight compared to stock?

If it's a hundred bucks or two, it might be a well worth investment; especially combined with a larger front pulley!

My only concern would be if the clutch can handle the extra force.


Terminology isn't my best, since English isn't my first language.

Title: Re: exhaust port
Post by badwolf on 01/29/16 at 23:03:33

If you think you can spend 5 minutes with a dremel tool and throw in a new piston and get a ton of extra HP, and someone will build you a custom pulley for $30, then you will run 85mph all day it' time to PUT THE X BOX DOWN AND COME BACK TO REALITY!  
Get the bike FIRST, and RIDE IT in the REAL world. Do you live somewhere there is no speed limit or other traffic? If you think you can and should ride real fast all the time, get a bike that's made to do so. You WILL be disappointed with a Savage quickly then start posting what a hunk of junk it is.
I'm not picking on you, just trying to give you some frank advise.

Title: Re: exhaust port
Post by Kris01 on 01/30/16 at 07:25:10

Higher octane won't give you any extra horsepower (unless your engine required it to start with). Stick with 85/87 octane with an 8:1 engine.

Title: Re: exhaust port
Post by justin_o_guy2 on 01/30/16 at 08:35:52

So far nobody has hopped one up enough to make the clutch slip.
Some have gone with stronger springs, I shimmed mine.
The clutch throw out is sintered metal and has been known to break with the stock springs and set-up.

Title: Re: exhaust port
Post by Kris01 on 01/30/16 at 09:29:42

I haven't heard one positive thing about beefing up the clutch. Anyone that has modified it has destroyed it. Look on Youtube. There's a famous (infamous?) video of a guy that turned his Savage clutch into shrapnel by trying to improve it.

Title: Re: exhaust port
Post by cheapnewb24 on 01/31/16 at 12:11:49

You mean this video....  ;)

https://www.youtube.com/watch?v=UmzGblbeDuU

That dude is not being very happy with Suzuki.  ::)

Title: Re: exhaust port
Post by KennyG on 01/31/16 at 13:33:54

Why do we waste so much time on this forum on things that we know don't work?

Kenny G

Title: Re: exhaust port
Post by Kris01 on 01/31/16 at 14:04:52

Yep, that's the one.  ;)

Title: Re: exhaust port
Post by verslagen1 on 01/31/16 at 14:17:20


152C372D6E6F5E0 wrote:
I haven't heard one positive thing about beefing up the clutch. Anyone that has modified it has destroyed it. Look on Youtube. There's a famous (infamous?) video of a guy that turned his Savage clutch into shrapnel by trying to improve it.

If you know what he did to destroy his clutch, I think we would benefit in knowing what not to do.

Title: Re: exhaust port
Post by justin_o_guy2 on 01/31/16 at 19:01:02


5C575A5E4F515A485D0D0B3F0 wrote:
You mean this video....  ;)

https://www.youtube.com/watch?v=UmzGblbeDuU

That dude is not being very happy with Suzuki.  ::)


I heard him say it had a bad clutch that slipped, so he had to mod it out, so it wouldn't slip.

He either had the wrong oil , couldn't adjust it, wrong rod, or didn't know how to ride. The clutch throw out Will break. The clutch itself is bulletproof, providing you don't put teflon in.

Title: Re: exhaust port
Post by Kris01 on 01/31/16 at 20:13:29

I don't know what he did but anyone that I've talked to that has tried stiffer springs or some other "upgrade" has detonated their clutch. What is the weak component?

BTW, a correction from an earlier post. It's actually 8.5:1, not 8:1 compression. Shouldn't matter by much though.

Title: Re: exhaust port
Post by Serowbot on 01/31/16 at 22:12:52

More,... ain't always better... :-?

Title: Re: exhaust port
Post by MeeLee on 02/08/16 at 09:19:00

Makes me wonder if the stock clutch can handle a larger (25t) front roller, for prolonged highway rides?
I ride it gently, but on the interstates I think I pretty much need to ride it with the throttle wide open.

Title: Re: exhaust port
Post by Dave on 02/08/16 at 09:39:20


567E7E577E7E1B0 wrote:
Makes me wonder if the stock clutch can handle a larger (25t) front roller, for prolonged highway rides?
I ride it gently, but on the interstates I think I pretty much need to ride it with the throttle wide open.


The clutch really doesn't care too much about final gearing.....it either can handle the engine power and will hold under full power.....or it can't and will slip.  The engine makes the same amount of power in any/every gear.....however your are more apt to notice slippage in the higher gears.  


I have about 4,000 miles on my double Kawasaki pulley set up, and about 6,000 miles since the engine modifications.  My clutch has stock plates and stock springs.  I have always used Rotella T....so I have never had a problem with any friction modifiers in my engine oil...my clutch does not slip, even in high gear under full power.  MMRanch and several others may have more miles on their 25T front pulley than I have.

I have never had any clutch problems on my Savage. I never apply full throttle until the engine is warned up, and when accelerating hard I never apply throttle until the clutch lever is fully released.

If you have clutch problems on the Savage - the clutch is out of adjustment, the plates are worn and you need to install a shorter clutch rod - or your plates are contaminated with Friction Modifiers, or somebody has abused your clutch and glazed the friction material (or any combination of the above).

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