SuzukiSavage.com - Do straight pipes cause valve problems?

Built2Last Serious Thumper Offline Tempt Fate Posts: 1447 FTF Gender:	Do straight pipes cause valve problems? 03/12/12 at 16:35:56 Do straight pipes on single cylinders cause floating valve or other serious engine problems over time? Is a drag pipe with a baffle considered a "straight pipe"?
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Serowbot

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Re: Do straight pipes cause valve problems?
Reply #1 - 03/12/12 at 18:39:14

Technically speaking,. I believe the answer is no...
...but,... the length and diameter of the pipe needs to be perfectly tuned...

In the real world,.. an open pipe will almost certainly cause exhaust pulses to revert back into the valve and overheat them, and that, in combination with lean conditions caused by an almost untunable power band will burn yer' valves...

Basically,.. it ain't a good idea.. and it'll run like crap... Huh

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arteacher

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Re: Do straight pipes cause valve problems?
Reply #2 - 03/12/12 at 19:28:14

Don't get your nighty in a knot there Built- the Raask is not a straight pipe. It has a restriction where the pipe joins the header which is about the same diameter as the inside of the baffle, (that's how you can clamp the two pieces together without a clamp showing), and the baffle runs pretty much the entire length of the muffler. A straight pipe is the same diameter over it's entire length.
Also, our bikes don't run like crap. Wink

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Built2Last Serious Thumper Offline Tempt Fate Posts: 1447 FTF Gender:	Re: Do straight pipes cause valve problems? Reply #3 - 03/12/12 at 19:55:00 I'm already in a knot, I'm having tuning problems with my pod air filter, and still that jingly sound... I guess it's the valves but I had them adjusted by a mechanic... Anyone know how many turns the stock air mixture screw on the side of the carb is?
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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: Do straight pipes cause valve problems? Reply #4 - 03/12/12 at 20:12:35 I guess it's the valves but I had them adjusted by a mechanic... Im sure thats a comfort after reading how the mechanics do these little bikes..
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Oldfeller--FSO Serious Thumper ModSquad Offline Hobby is now "concentrated neuropany" Posts: 12671 Fayetteville, NC Gender:	Re: Do straight pipes cause valve problems? Reply #5 - 03/12/12 at 20:20:56 Especially if the "mechanic" doesn't shave or vote yet and he still thinks his un-annotated copy of Clymers is the whole gospel truth .....
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arteacher

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Re: Do straight pipes cause valve problems?
Reply #6 - 03/12/12 at 20:30:36

"Anyone know how many turns the stock air mixture screw on the side of the carb is?"
Stock it's 1 3/4 turns out, but you are way beyond "stock".
If your having trouble tuning it I would get rid of the cone filter and put a K&N slab filter in the stock air box. That, and the Dial-a-Jet, is the difference between yours and mine and I didn't have any trouble tuning mine. I don't know if you have done a spacer mod or not- I have a 2/3 spacer in mine.

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Built2Last

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Re: Do straight pipes cause valve problems?
Reply #7 - 03/13/12 at 06:40:12

arteacher wrote on 03/12/12 at 20:30:36:

"Anyone know how many turns the stock air mixture screw on the side of the carb is?"
Stock it's 1 3/4 turns out, but you are way beyond "stock".
If your having trouble tuning it I would get rid of the cone filter and put a K&N slab filter in the stock air box. That, and the Dial-a-Jet, is the difference between yours and mine and I didn't have any trouble tuning mine. I don't know if you have done a spacer mod or not- I have a 2/3 spacer in mine.

Ryca recommends 1 1/2 turns in their youtube carb tuning video as a starter, seems like my engine is at max rpms at 60mph with 1 1/2 turns.. I'm doing the spacer mod at around 2.5mm with brass and stainless washers...

I have torque to blast up a hill in the twisties but not the speed on flat land anymore.. aha

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arteacher Serious Thumper Offline Ride as if your naked and invisable! Posts: 2581 London ontario Gender:	Re: Do straight pipes cause valve problems? Reply #8 - 03/13/12 at 07:15:13 Mine will do 90 + with my 250lb a$$ on it.
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Built2Last

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Re: Do straight pipes cause valve problems?
Reply #9 - 03/13/12 at 07:32:43

arteacher wrote on 03/13/12 at 07:15:13:

Mine will do 90 + with my 250lb a$$ on it.

I just need to tune this.. I'm thinking 60 pilot, spacer mod, play with the idle screw and the air mixture screw.. possibly even experiment with a 157.5 to 160 main... it all got crazy out of wack when I threw that pod air filter on the carb boot... My pod is attached to the rubber carb boot, hopefully creating a wind tunnel... besides, with the stock air box I won't have room for the fake oil bag Cheesy

There is no going back to the air box... I refuse to walk across the room and pick it up off the tiny work bench...

http://www.knfilters.com/search/product.aspx?Prod=rc-1920

I'm gonna try backing the air mixture screw out to 3 turns aha..

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Re: Do straight pipes cause valve problems?
Reply #10 - 03/13/12 at 07:56:03

Built2Last wrote on 03/13/12 at 06:40:12:

Ryca recommends 1 1/2 turns in their youtube carb tuning video as a starter, seems like my engine is at max rpms at 60mph with 1 1/2 turns.. I'm doing the spacer mod at around 2.5mm with brass and stainless washers...

I have torque to blast up a hill in the twisties but not the speed on flat land anymore.. aha

The idle mixture screw has nothing to do with 60 mph unless you're going in 5th gear and going downhill.

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Built2Last

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Re: Do straight pipes cause valve problems?
Reply #11 - 03/13/12 at 08:01:16

verslagen1 wrote on 03/13/12 at 07:56:03:

Built2Last wrote on 03/13/12 at 06:40:12:

Ryca recommends 1 1/2 turns in their youtube carb tuning video as a starter, seems like my engine is at max rpms at 60mph with 1 1/2 turns.. I'm doing the spacer mod at around 2.5mm with brass and stainless washers...

I have torque to blast up a hill in the twisties but not the speed on flat land anymore.. aha

The idle mixture screw has nothing to do with 60 mph unless you're going in 5th gear and going downhill.

I was talking about the air mixture screw on the right side of the carb, the one you need the tiny screw driver for

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spacepirates

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Re: Do straight pipes cause valve problems?
Reply #12 - 03/13/12 at 09:03:08

The idle mixture screw (air mixture screw, D*%n soft brass screw on the right side, whatever) has very little to do with engine performance beyond idle (hence the moniker "idle mixture screw" in addition to "air mixture screw"). it really only affects idle. Once the throttle is engages you get into the needle jet/jet needle area, and finally once you are closing in on WOT, the main jet.

There is a diagram of where each fuel circuit is in play somewhere in the tech section. Also in the tech section are two nice and handy jetting guides.

To paraphrase and sum up the idle mixture screw tuning part:
- with the bike off, turn the idle mixture screw all the way in, then count it two full turns out
- start the bike and using the idle speed screw (left side), bump up your idle a bit (makes things a bit easier to hear, less likely to die).
- back the idle mixture screw out slowly, count 1/4 turns at a time (waiting a tad between each adjustment), until revs start to drop
- from that position, count 1/4 turns again until the revs drop again (so you'll turn the screw through the "happy idle" range).
- divide the number of turns from "screw too far out and rough idle" to "screw too far in and rough idle" in half, and set the screw there. should be pretty close to ideal jetting if the pilot is the right size.

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Built2Last Serious Thumper Offline Tempt Fate Posts: 1447 FTF Gender:	Re: Do straight pipes cause valve problems? Reply #13 - 03/13/12 at 09:14:39 Thanks Spacepirates, I'll give this a try
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Serowbot YaBB Moderator ModSquad Offline OK.... so what's the speed of dark? Posts: 28653 Tucson Az Gender:	Re: Do straight pipes cause valve problems? Reply #14 - 03/13/12 at 10:34:25 So,.. I'm confused... Are you trying to tune a straight pipe, no pipe, or a Jardine?... ...
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