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Message started by Dooley on 02/08/13 at 10:22:06

Title: Question about running lean and heat issue
Post by Dooley on 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

Title: Re: Question about running lean and heat issue
Post by arteacher on 02/08/13 at 10:56:01

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

Title: Re: Question about running lean and heat issue
Post by Serowbot 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)..
:-?...

Title: Re: Question about running lean and heat issue
Post by Dooley on 02/08/13 at 11:04:19


747F7F767A75746E6F1B0 wrote:
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?  

Title: Re: Question about running lean and heat issue
Post by Dooley on 02/08/13 at 11:14:18


283E29342C39342F5B0 wrote:
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)..
:-?...


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  

Title: Re: Question about running lean and heat issue
Post by WD on 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...  >:( 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).

Title: Re: Question about running lean and heat issue
Post by Dooley on 02/08/13 at 12:43:00

Thanks again for the advice. I hope to get her running tight soon.

Title: Re: Question about running lean and heat issue
Post by MiCTLaN 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.

Title: Re: Question about running lean and heat issue
Post by Blinky 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

Title: Re: Question about running lean and heat issue
Post by Gyrobob 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 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.

Title: Re: Question about running lean and heat issue
Post by Dooley on 02/10/13 at 10:18:14


49777C616C616C0E0 wrote:
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.

Title: Re: Question about running lean and heat issue
Post by Dooley on 02/10/13 at 10:25:33


41454F58404D422C0 wrote:
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.

Title: Re: Question about running lean and heat issue
Post by Dooley on 02/10/13 at 10:27:40


5E594F56563A0 wrote:
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.

Title: Re: Question about running lean and heat issue
Post by justin_o_guy2 on 02/10/13 at 10:51:48


447A716C616C61030 wrote:
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.  

Title: Re: Question about running lean and heat issue
Post by Dooley on 02/10/13 at 11:05:45


3A252324393E0F3F0F37252962500 wrote:
[quote author=447A716C616C61030 link=1360347726/0#9 date=1360436821]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.  [/quote]


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

Title: Re: Question about running lean and heat issue
Post by hexnut on 02/10/13 at 12:21:46

gone fishing

Title: Re: Question about running lean and heat issue
Post by Gyrobob on 02/11/13 at 03:10:27


33343F3F3C35296762500 wrote:
[quote author=3A252324393E0F3F0F37252962500 link=1360347726/0#13 date=1360522308][quote author=447A716C616C61030 link=1360347726/0#9 date=1360436821]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.




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


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.
[/quote]


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[/quote]


Yes, I meant mixture, not temp.  Good catch.

There are two situations which can lead to the mixture burning too soon, and eventually doing damage.
-- Preignition, where the mixture is ignited before the spark occurs, mostly caused by hot spots acting like a glow-plug in a model aircraft engine.
-- Detonation, where the spark ignites the mixture, but for any of several reasons, the mixture explodes instead of burning evenly.  Lean mixtures could cause this.

Here is a really good explanation of the difference between the two:

http://www.misterfixit.com/deton.htm

Title: Re: Question about running lean and heat issue
Post by Dave on 02/12/13 at 13:13:16

The engine will not run if it goes beyond the limits of too lean or too rich.  Generally this situtaion does not occur at all throttle settings simultaneously - so generally you will get an engine that can be started, but may not idle, or may not take throttle, etc.  When an engine gets really lean they tend to backfire through the carb when you open the throttle....however the CV carb might mask this situation a bit as the drop in vacuum will allow the diaphragm to drop - which will increase the vacuum and pull in more fuel.

You might be overthinking this...without trying some things yourself.  You should do the standard 3 washer trick....and see how it works on yoru bike.    


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