SuzukiSavage.com - Rich or Lean

milesb

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Rich or Lean - how to tell?
07/15/05 at 17:10:21

How do you tell if the bike is running rich or lean? Outside of the stock spacer being removed, the carb has not been modified to my knowledge and I'm not one to tinker with the carb (small parts are not my forte).

I drilled the muffler baffle and the bike runs fine, albiet a bit louder. But I'd like to know if it's running lean or rich.

From reading other posts here and in the tech section, seems it's best to run the bike at idle and adjust the air mixture screw until it's between the two points where the RPM's drop. Is this correct?

Next basic question: The carb still has the plug over the mixture screw (so I'll assume it's at the factory setting of three turns out from full in?) - I've read where you have to drill out the plug, is it threaded where I can use a bit slightly larger than the hole in the plug and back it out?

Thanks in advance,

Miles

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Savage_Greg

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Re: Rich or Lean - how to tell?
Reply #1 - 07/15/05 at 19:42:25

milesb wrote on 12/31/69 at 16:00:07:

How do you tell if the bike is running rich or lean? Outside of the stock spacer being removed, the carb has not been modified to my knowledge and I'm not one to tinker with the carb (small parts are not my forte).

I drilled the muffler baffle and the bike runs fine, albiet a bit louder. But I'd like to know if it's running lean or rich.

From reading other posts here and in the tech section, seems it's best to run the bike at idle and adjust the air mixture screw until it's between the two points where the RPM's drop. Is this correct?

Next basic question: The carb still has the plug over the mixture screw (so I'll assume it's at the factory setting of three turns out from full in?) - I've read where you have to drill out the plug, is it threaded where I can use a bit slightly larger than the hole in the plug and back it out?

Thanks in advance,

Miles

If you drilled out the muffler baffles, it is leaner than stock because you increased the air flow. Plain and simple. Get a 150 - 152.5 main jet and it will be better.

I don't think the stock setting on the screw is 3 turns...in fact, I don't think that it is a "determined" setting. I think it is adjusted on a "bench" with a particular flow setting for each carb. They wouldn't have adjustments if they could "fix" it because there are always manufacturing differences.

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Reelthing

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Re: Rich or Lean - how to tell?
Reply #2 - 07/15/05 at 21:32:31

this is the correct way to tell - read the plug - but it's a pain in the arse - if you haven't modified the engine a 150-152.5 mainjet, freeer flowing pipe - 152.5 or a 155,
1.5-2.0 turns out on the idle mixture, and a 1/3-1/2 the spacer - and you'll be real close.

http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1112528489

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Savage_Greg

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Re: Rich or Lean - how to tell?
Reply #3 - 07/16/05 at 08:27:50

milesb wrote on 12/31/69 at 16:00:07:

How do you tell if the bike is running rich or lean? Outside of the stock spacer being removed, the carb has not been modified to my knowledge and I'm not one to tinker with the carb (small parts are not my forte).

I drilled the muffler baffle and the bike runs fine, albiet a bit louder. But I'd like to know if it's running lean or rich.

From reading other posts here and in the tech section, seems it's best to run the bike at idle and adjust the air mixture screw until it's between the two points where the RPM's drop. Is this correct?

Next basic question: The carb still has the plug over the mixture screw (so I'll assume it's at the factory setting of three turns out from full in?) - I've read where you have to drill out the plug, is it threaded where I can use a bit slightly larger than the hole in the plug and back it out?

Thanks in advance,

Miles

Back at it again...since the spacer is out, your mid range was probably a little fat, and since you drilled the baffles that may be a little leaner, now. However, as I have suggested for years, the spacer should be about 1/2 the original thickness. Not completely removed....just something I figured from trial and error, and checking the plug and the exhaust.

You have the right idea about the idle mixture screw, but first you need to get at it. Gently drill out the plug. Go slowly with very light pressure and use a drill about 3/4 the size of the plug...if it is like mine were, the plug will come out on the end of the drill. Then when you adjust it, just split the difference in the number of turns in and out and forget about it. Then adjust your idle speed if needed.

BTW - on a really rich engine you can see black smoke puffing out of the exhaust on bright sunny day. You may even be able to smell gasoline, too. But at this point, I don't think you have to worry about that.

Just for good measure, if that is all the modification that you plan to do, a 1/2 spacer and a 152.5 main will most likely fix things just about right for you.

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milesb Ex Member	Re: Rich or Lean - how to tell? Reply #4 - 07/16/05 at 11:07:00 Thanks Greg. That's just the info I was looking for. No more mods planned. Just wanted to get a little noise to make the presence known (that along with the shirt I made up that says on the back, "Dive Now, Talk Later!" for our cell phone loving friends). Miles
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Savage_Rob Serious Thumper Alliance Member Offline Mechanically Inclined Amateur Posts: 6972 Texas (Dallas area) Gender:	Re: Rich or Lean - how to tell? Reply #5 - 07/16/05 at 21:54:33 milesb wrote on 12/31/69 at 16:00:07: Just wanted to get a little noise to make the presence known (that along with the shirt I made up that says on the back, "Dive Now, Talk Later!" for our cell phone loving friends). I sure hope that was supposed to be "Drive Now..."
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milesb Ex Member	Re: Rich or Lean - how to tell? Reply #6 - 07/16/05 at 22:42:26 Savage_Rob wrote on 12/31/69 at 16:00:07: I sure hope that was supposed to be "Drive Now..." whoops, yeah - that's "Drive Now"
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