Running Lean

[CSUAdam]

My R6 used to run rich, at least I think because it would spit carbon out of the can, so I installed a BMC filter thinking it would even it out. Well, now I think it is running lean. In first gear if I have the throttle all the way open, when it reaches 10000 it starts to studder and jerk like it's kinda running out of gas. I don't have this problem if I roll onto it a little slower and it's not as bad in 2nd but I can still feel it a little. So what can I do? Can I just adjust the pilot screw? How far should I turn it? Any help would be appreciated.

Oh, it's an 02 R6 with a D&D slip-on and the filter, nothing else.

[Nick_Ninja]

VALVES --- VALVES .............. when was the last time you adjusted your valves If they're outta whack -- this can cause lame top-end performance [intake and exhaust].

check'um

[Bryce]

I would tend to say at 10k I would try raising the main jet about one step

[Napalm]

From about 3/4 to wide open throttle is where the main jet circut kicks in.

The only thing you can do to fix the lean is to install slightly larger main jets.


Napalm

[BladeRider]

Have you tried taking the bmc filter off and running with the old one to see if the change is what caused the problem?

I would pull the plugs and see how fouled out they are. Sometimes lousy dirty plugs will cause this type of high rpm miss.

By having the D&D slipon and adding a better breathing air filter, you've increased the airflow through the motor which will change the air/fuel ratio unless you rejet the carb to compensate. Jetting a carb correctly is alot of trial and error if you don't have the right equipment to check the exhaust and help dial it in. A reputable shop that does this kind of work might be your best bet. Just blindly turing screws will get ya into trouble.

Tom

[Anonymous]

So was the jetting stock when you got it? If it was then the bike was jetted for sea level to begin with (so yeah it probably was rich), so leaning it out probably put it back closer to where it should be. I have a very hard time believing a stock carb would go too lean with a BMC and slip on at this altitude.

Like someone else said, pull the plugs (all of them, just remember which one went where) and see what they look like. Post a description here if you don't know how to read them and someone can tell you what the colors/condition of them means.

[CSUAdam]

I'm going to try installing the stock filter again to see how it runs. I wouldn't think it has anything to do with the valves like Nick mentioned. The bike only has 3500 miles so unless something went out of whack I don't think thats it.

I'll let you know how it runs after I install the old filter.