SuzukiSavage.com - Question about running lean and heat issue

Dooley

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Question about running lean and heat issue
02/08/13 at 10:22:06

I recently installed a dyna muffler and I am very happy with it so far. I was going to install the cheap hi flow Nu-foam air filter as I am cheap and broke and any place I can save a buck I do so. Well when I went to install it it turns out that I already have a K&N drop in installed. I am assuming that the Nu Foam poor mans mod is trying to emulate the K&N style, am I correct in this assumption? At the same time I replaced my tires with the rear tire being a 140/90. Now these 2 changes only I have noticed a increase in HP I guess well lets just say more power. I feel like I have gained a gear. What do you guys think that would equate to as far as HP?

Well back to my real question. I have not re-jetted that carb and I know we run lean to begin with. I have also read that running to lean could cause heat issues. Now I have not run the bike very hard yet because I want to break in the tires. I have heard that you do not really have to worry about it. But considering that all this started from laying her down because of bad tires I am not going to rush or push it. But how concerned do I need to be about the heat issue that I read about? I mean I read it can be as bad as the engine can be seized up. And how can I know if I am going into that danger zone?

Sorry for being so wordy but I thought more info the better.

Thanks
Dooley

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arteacher Serious Thumper Offline Ride as if your naked and invisable! Posts: 2581 London ontario Gender:	Re: Question about running lean and heat issue Reply #1 - 02/08/13 at 10:56:01 Look at this:http://suzukisavage.com/cgi-bin/YaBB.pl?num=1309246277
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Re: Question about running lean and heat issue
Reply #2 - 02/08/13 at 10:57:36

K/N is good... keep it..
Muffler should add a horsie or two,.. and taller rear tire will add 5% to gearing...
(Your speedo will read correct now)...

New tires are very slick for the first 50 miles,.. be careful...

Jetting,... I doubt you will damage the engine with stock jets,.. but you might get a little more power, and less popping if you go up a step or two...
Try a #150 or $152.5 main (large round Mikuni)... and do the 2/3 spacer mod if you like... I'd keep the pilot stock for gas mileage, (that's just me, I like 60mpg's)..
Huh

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Dooley

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Re: Question about running lean and heat issue
Reply #3 - 02/08/13 at 11:04:19

arteacher wrote on 02/08/13 at 10:56:01:

Look at this:http://suzukisavage.com/cgi-bin/YaBB.pl?num=1309246277

Believe me I have read that more than once. And I know I have to re-jet the carb without question. I am just wondering if there is a danger of the engine seizing up in the mean time due to heat? Or am I just being a little paranoid?

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Dooley

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Re: Question about running lean and heat issue
Reply #4 - 02/08/13 at 11:14:18

Serowbot wrote on 02/08/13 at 10:57:36:

K/N is good... keep it..
Muffler should add a horsie or two,.. and taller rear tire will add 5% to gearing...
(Your speedo will read correct now)...

New tires are very slick for the first 50 miles,.. be careful...

Jetting,... I doubt you will damage the engine with stock jets,.. but you might get a little more power, and less popping if you go up a step or two...
Try a #150 or $152.5 main (large round Mikuni)... and do the 2/3 spacer mod if you like... I'd keep the pilot stock for gas mileage, (that's just me, I like 60mpg's)..
Huh

...

Thanks for the advice, I plan on doing the spacer mod when I do the re jet. Would knowing I live in florida change your advice on the jet size? What do you think of the dial-a-jet system? I am new to this wrenching thing and it seems like an easy way to go about it. I will say this though I am loving it!! I am a computer geek and it is really nice to dig something new that involves using my hands. And there are many similarity's to the two. The trouble shooting, problem solving and just out right putting the pieces of the puzzle together.

BTW I can not thank you guys and this site enough. Without it I would be as lost as a grandmother trying to fix a computer.

Thanks,
Dooley

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WD

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Re: Question about running lean and heat issue
Reply #5 - 02/08/13 at 12:22:32

Florida? One step up, tops. I'm outside Memphis at about 420' elevation, with 55/155 jets and she smokes like an old diesel. Too much fuel. Was fine in the mountains out west, with the wetter air here I'm running it way too fat. I'll likely step it back down to stock pilot and a +1 main and get some fuel economy back. Between the fat jets and the apehangers my bike is down to 36 mpg... Angry

My other bikes when done should get in the 85-100 mpg range (CL100 and CL250 Scramblers). My Savage got in the 70s and 80s with a free breathing muffler and everything else left alone (except the air screw out another 1.5 turns).

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Dooley YaBB Newbies Offline Posts: 42 Palm Harbor, FL Gender:	Re: Question about running lean and heat issue Reply #6 - 02/08/13 at 12:43:00 Thanks again for the advice. I hope to get her running tight soon.
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MiCTLaN

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Re: Question about running lean and heat issue
Reply #7 - 02/08/13 at 12:47:29

I'm also in Florida and after installing the Dyna on mine I went up one size on the main and did the spacer mod (with the washers included in the jet kit, rather than modifying the stock spacer), left the stock pilot. I get small pops between gears, but nothing like the solid backfires that I was getting with the stock exhaust before I replaced the exhaust and worked on the carb. I'm still running the stock filter though.

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Blinky-FSO

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Re: Question about running lean and heat issue
Reply #8 - 02/08/13 at 12:54:16

Dooley,
Dave pointed me in this direction and it is working well. I have a Dyna and the K&N drop in filter in the stock air box. I kept the stock 52.5 pilot and moved to a 150 main jet. I replaced the white spacer with 3 washers and have the mixture screw at about 1.5 turns. Good throttle response and just the right amount of gurgle in the exhaust during shifts.

Good Hunting

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Gyrobob

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Re: Question about running lean and heat issue
Reply #9 - 02/09/13 at 11:07:01

Max cylinder temp happens with a perfect stoichiometric ratio, approx 14.7:1. If you are rich (maybe 12:1) or lean (maybe 16:1) of that point, the cylinder temp goes down.

The danger from lean mixtures is from detonation, not heat. Lean mixtures can burn unevenly, or even too rapidly which can lead to detonation, even though the temps are not as high as with a 14.7:1 ratio.

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« Last Edit: 02/11/13 at 03:01:55 by Gyrobob »

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Dooley

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Re: Question about running lean and heat issue
Reply #10 - 02/10/13 at 10:18:14

Gyrobob wrote on 02/09/13 at 11:07:01:

Max cylinder temp happens with a perfect stoichiometric ratio, approx 14.7:1. If you are rich (maybe 12:1) or lean (maybe 16:1) of that point, the cylinder temp goes down.

The danger from lean mixtures is from detonation, not heat. Lean temps can burn unevenly, or even too rapidly which can lead to detonation, even though the temps are not as high as with a 14.7:1 ratio.

Could you explain this in a more layman's terms? Not sure I understand the difference in the detonation to heat characteristic.

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Dooley

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Re: Question about running lean and heat issue
Reply #11 - 02/10/13 at 10:25:33

MiCTLaN wrote on 02/08/13 at 12:47:29:

I'm also in Florida and after installing the Dyna on mine I went up one size on the main and did the spacer mod (with the washers included in the jet kit, rather than modifying the stock spacer), left the stock pilot. I get small pops between gears, but nothing like the solid backfires that I was getting with the stock exhaust before I replaced the exhaust and worked on the carb. I'm still running the stock filter though.

How many washers? Did you try more the one amount and OK i am good with that. Or did you try say 2 and then 3 to find one works better then the other. I am planning on trying 3 first.

Little pissed right now because I did the seat mod yesterday and thought I might as well do the space mod. Got all but 3 screws off top of carb. 3rd stripped. darn IT. I guess harbor freight will see me soon for an impact driver.

P.S seat mod on a one seat is more then the spacers. But I lucked out and had all the rubber from my old pegs and cut them to fill in the gaps and prevent seat bending. Seems to have worked great.

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Dooley

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Re: Question about running lean and heat issue
Reply #12 - 02/10/13 at 10:27:40

Blinky-FSO wrote on 02/08/13 at 12:54:16:

Dooley,
Dave pointed me in this direction and it is working well. I have a Dyna and the K&N drop in filter in the stock air box. I kept the stock 52.5 pilot and moved to a 150 main jet. I replaced the white spacer with 3 washers and have the mixture screw at about 1.5 turns. Good throttle response and just the right amount of gurgle in the exhaust during shifts.

Good Hunting

did you try 2 washers and then 3 to find out 3 was what worked for you? I know Tenn is not that much of a climate change so what works for you might work well for me. Well at least not until winter,,, We do not have that lol.

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justin_o_guy2

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Re: Question about running lean and heat issue
Reply #13 - 02/10/13 at 10:51:48

Gyrobob wrote on 02/09/13 at 11:07:01:

Max cylinder temp happens with a perfect stoichiometric ratio, approx 14.7:1. If you are rich (maybe 12:1) or lean (maybe 16:1) of that point, the cylinder temp goes down.

The danger from lean mixtures is from detonation, not heat. Lean temps can burn unevenly, or even too rapidly which can lead to detonation, even though the temps are not as high as with a 14.7:1 ratio.

Lean temps can burn unevenly, or even too rapidly which can lead to detonation.

Im thinking Bob meant to say Lean Mixtures can burn unevenly blahdeblaaahblaah & so on,,

Im gonna step out on a limb here & TRy to explain the part about detonation. Im just takin a shot at it, based on my understanding of how an engine is built & what happens & when in the power cycle.

While the piston is coming up on compression the air in the cylinder get hotter, Boyles Law, IIRC, Halve the volume doubles the pressure & temperature. Compress stuff 9 to 1? Shazzam,, gets Hot, grab the line coming outta the compressor head,,
Anyway, if the fuel gets hot enough to catch on fire before the spark plug fires, thats detonation. If its doing that while the piston is still headed up, then thats pounding the POO outta bearings at the very least. What other damage mite it cause? I Dunno,, Thats just MY imagination at work there.

What does it matter that flame front propagation is uneven? I can see it affecting power, but I dont see it hurting equipment. Bob may well correct me on that.
I hope others will explain further the problems detonation can cause.

Exhaust gurgle,, its worth buying a bike just to hear it.

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Dooley

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Re: Question about running lean and heat issue
Reply #14 - 02/10/13 at 11:05:45

justin_o_guy2 wrote on 02/10/13 at 10:51:48:

Gyrobob wrote on 02/09/13 at 11:07:01:

Max cylinder temp happens with a perfect stoichiometric ratio, approx 14.7:1. If you are rich (maybe 12:1) or lean (maybe 16:1) of that point, the cylinder temp goes down.

The danger from lean mixtures is from detonation, not heat. Lean temps can burn unevenly, or even too rapidly which can lead to detonation, even though the temps are not as high as with a 14.7:1 ratio.

Lean temps can burn unevenly, or even too rapidly which can lead to detonation.

Im thinking Bob meant to say Lean Mixtures can burn unevenly blahdeblaaahblaah & so on,,

Im gonna step out on a limb here & TRy to explain the part about detonation. Im just takin a shot at it, based on my understanding of how an engine is built & what happens & when in the power cycle.

While the piston is coming up on compression the air in the cylinder get hotter, Boyles Law, IIRC, Halve the volume doubles the pressure & temperature. Compress stuff 9 to 1? Shazzam,, gets Hot, grab the line coming outta the compressor head,,
Anyway, if the fuel gets hot enough to catch on fire before the spark plug fires, thats detonation. If its doing that while the piston is still headed up, then thats pounding the POO outta bearings at the very least. What other damage mite it cause? I Dunno,, Thats just MY imagination at work there.

What does it matter that flame front propagation is uneven? I can see it affecting power, but I dont see it hurting equipment. Bob may well correct me on that.
I hope others will explain further the problems detonation can cause.

Exhaust gurgle,, its worth buying a bike just to hear it.

I understand. Like a diesel engine fires with out a spark plug due to pressure. So on an extremely lean engine there can be a detonation happen before the actual "ignition".

What would cause of such a lean setting that would cause this? I would think that at some point would the bike even run with so little flue? Would you know it if you heard it?

Thanks
Dooley

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