Doc or Musky, my '07 has the speedstar air can and K&N filter, and the exhaust stage one drill out of the stock mufflers. The bike, I believe is running a bit lean due to:
(1) Plugs burning dark gray without carbon buildup.
(2) Exhaust shows very little carbon but is still black in color
(3) Engine is extremely cold-blooded. Start fine, but demands help from the enricher for up to 1 or 2 miles, even in 60+ degree weather.
Also during the warmup riding period, it is very apt to sputter and backfire when blipping the throttle or shifting.
Other than those items, it runs fine, cruises smoothly, and gets 43 to 45 mpg at speeds around 70 to 75 mph.

My question is, can running too lean damage the engine? Does this make it run hotter? Would you recommend rejetting even if I don't need the extra horsepower?

If I need to rejet anyway, then I'll probably go ahead with some aftermarket pipes (bust the budget this year), and depend on you guys walking me through the rejet process.

Also, I run the 87 octane, and add 4 to 6 oz of MMO about every third tank.

Thanks, and I really appreciate all the info you guys add to this forum.

dryriver wrote:
Doc or Musky, my '07 has the speedstar air can and K&N filter, and the exhaust stage one drill out of the stock mufflers. The bike, I believe is running a bit lean due to:
(1) Plugs burning dark gray without carbon buildup.
(2) Exhaust shows very little carbon but is still black in color
(3) Engine is extremely cold-blooded. Start fine, but demands help from the enricher for up to 1 or 2 miles, even in 60+ degree weather. Also during the warmup riding period, it is very apt to sputter and backfire when blipping the throttle or shifting. Other than those items, it runs fine, cruises smoothly, and gets 43 to 45 mpg at speeds around 70 to 75 mph.

Everything sounds like it should be. In fact you could be a slightly on the rich side but I would not worry about it. Don't blip, especially when could or you'll kill the engine.

My question is, can running too lean damage the engine?

Yes ... but you are not too lean.

Does this make it run hotter?

Leaner is hotter.

Would you recommend rejetting even if I don't need the extra horsepower?

No but to what do you want to rejet it?

Doc

Well, you're letting in a lot more air but even stage one on the pipes is pretty restrictive. That could mess up the A/F mixture. You could put the stock airbox back on until you go to stage 3 or get new pipes. Then rejet. That's my thoughts on it anywho.

Edit. Look here - Reading plugs
Does the description for overheated sound like what your plugs look like?

Mine look more like the normal pic but just a bit darker. Thanks for the input, but since you put me on to the cobras for sale on delphi, I'm probably going to have to rejet anyway.
As usual, you guys are right-on with the advice. Thanks

Wanted you to look at the plug page just in case. Usually if you do manage to get these bikes too lean they run like fried crap or don't run at all. So are you getting the Cobras?

What Musky said ...you also get pinging ...Coug

Yeah, Musky. Just waiting for payment instructions. Planned on saving this expense until next spring, but he has some nice pipes at a good price, so there went my ability to say no.
Thanks again for sending me in the right direction.


"At that point I had the right to remain silent, I just didn't have the ability." Ron White

dryriver wrote:
. Thanks again for sending me in the right direction.

You're welcome.

OK, I am lost, lets say that the bike is setup correct to start, then you play with the airbox and filter, now you are allowing more air so I would think that this will crate a LEAN condition, since we increased air but did not increaed gas, how is it possible that he may be rich (too much gas) Sorry it this is a stupid question, but I guess I need to ask

DarekC

Can someone please explain my question from a post above.

Cheers DarekC