running lean?

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Mar 5, 2006 | 10:05 PM

stock28

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running lean?

I have an 06 Street Bob with a stage 1 including Sreaming Eagle II's. I had the stage 1 done before I picked it up. I only have about 250 miles on her so far but noticed when I first start it up, I get a little bit of black/grey smoke out the pipes especially if I rev it a bit. I haven't noticed it after it's warmed up. Is this normal at all or may I be running to lean? There are no pops or anything and there are no flat spots throughout the rev range.

Mar 6, 2006 | 12:50 PM

CraigC

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From: West Tennessee

RE: running lean?

This is normal. Black smoke is an indication of the engine running rich, which is basically what it's doing at startup. The EFI richens the mixture at startup just like you would by pulling out the choke on a carbed bike.

Mar 6, 2006 | 02:09 PM

stock28

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RE: running lean?

Thanks, I just wanted to be sure I wasn't having a problem.

Mar 7, 2006 | 03:31 PM

carver

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From: Williamston, Michigan

RE: running lean?

I've read alot about the new EFI bikes running borderline lean, especially, if you change the exhaust without a remap of the EFI. I was just wondering (I'm obviously, not a mechanic), will running your engine lean harm it? I read where you have to check the sparkplugs often to see if your bike is running too lean, etc. Will I ruin my bike if I install new screaming eagle slip ons and it does run a little lean. Does running lean effect performance?

Mar 7, 2006 | 08:31 PM

KBFXDLI

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From: USA

RE: running lean?

CAll the dealer and see if they installed the ECM download when they did the Stage1 if they did not get it done. You can read about this in the tech threads & DIY threads.

Mar 7, 2006 | 09:30 PM

stock28

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RE: running lean?

Yes, they did the download and the bike runs great. I was just concerned about the smoke at start up.

Mar 7, 2006 | 10:39 PM

CraigC

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From: West Tennessee

RE: running lean?

Quote:

ORIGINAL: carver

...will running your engine lean harm it?.

Absolutely! Lean running causes excess heat. Worse news for an air cooled engine. They're slightly lean from the factory, some borderline, some worse. A little leaner, performance will suffer and you will know it. If it's lean enough, it can destroy your engine.