y is it lean?!?!?!?!

[oglejust]

my 04 crf 450 has been lean since the 1st time it was started... 3 weeks ago, it sat in a climate controled shop with the carb drained for 5 years and since its been started its been lean... its alright with a # 60 pilot in it but something else has to be wrong to need a 60 pilot, i put a new exhaust gasket on it and its not an air leak at the carb as ive sprayed carb cleaner all around it to listen for it reving up... any ideas?

[dstollys]

what size main jet are you running? elev. your riding at? anything else you might think would help

[oglejust]

im in east central illinois so 1000-2500ft anywhere between 70-85* stock is a 42 pilot and a 165 main, it backfires really bad with the 42 so i put in a 45... same thing, go with a 60 and its good enough to ride it but theres got to be something wrong... it shouldnt need a 60! i still have the stock main in it and the needle is stock... i lifted the needle 1 notch the other day but it didnt help so i put it back stock. ive checked for intake leaks, exhaust leaks, and just now i took off the carb, cleaned the pilot circuit (screw, jet, and slow air jet) cleaned with cleaner and compressed air and still popping! the bike had never been started and it was like this so i really cant see it being the valves, especially if a bigger pilot fixes it. wat could be wrong im sooooo sick of fighting this thing

[oglejust]

help please!

[dogger315]

Try switching carbs with your friends bike then ride it a few minutes.
If it performs normally, you know it's a carb problem and nothing else.

Since the bike runs fine except when you chop the throttle, it has to
be the pilot circuit. A small amount of hardened residue or casting
trash can obstruct the passage enough to cause a lean condition.
This theory is reinforced by the fact that a #60 jet (which essentially
provides unobstructed fuel flow) improves the condition. If a #45 pilot
doesn't improve the lean condition, then the obstruction is probably
occuring downstream of the jet causing the circuit itself to function as
a jet.

I know you cleaned the carb, but if this is a case of fuel varnish, you will
need to soak the carb body in carburetor cleaner for several hours followed
by a suitable brush to chase out the circuit. Finish with a compressed air
knozzle with a needle attachment to force the air through the circuit. If
it's casting debris (metal particles), try a pipe cleaner or fine wire (very
carefully) to clear the circuit.

dogger