Popping or backfiring at idle is probably a symptom of it being lean. If your airscrew is on the airbox side close it a bit.
What you can do is warm up the bike, set it to a fast idle, and adjust the airscrew to the max rpm (by ear in your case).
Once it is adjusted for max rpm...that's it for the airscrew.
Also, it won't be the main jet...the main is responsible for 1/2-full throttle more than anything else.
The pilot/slow jet is responsible for the idle to 1/4 throttle....then the needle from 1/4 to 1/2 or so...then the main take it to redline.
(They all overlap a tad.)
Last edited by Spiider; 05-03-2012 at 01:24 PM.
See the video below, this guy explains carburetor operation and the adjustment process very well.
How to adjust the jets on motorcycle carburetors
On saturday my buddy topped up his R6 at a ghetto-looking gas station on the 118, just a few kms east of Haliburton. As soon as we got on the street his engine died with very similar symptoms as OP. Bike would idle (usually) but throttle was mostly unresponsive. Also sounded like it was knocking quite a bit. The station had regular gas on one side of the pump and diesel on the other so we thought diesel might've somehow been mixed in or the gasoline was just dirty.
I ended up riding into town, borrowed a jerry can from a gas station that had 91 octane, popped into home hardware to grab a siphon hose and rode back... all the while spilling fuel out the vent hose of the jerry can down my back and butt crack lol. It stung but there was no cover for it. After swapping fuel the bike was fine.
Is this most likely just old gasoline sitting in the pumps or would diesel have a similar effect?
Diesel would have similar affects on the bike but with more smoke and probably wouldn't at all.
If you had to siphon it, you'd know diesel as soon as you smelled it or saw it. Diesel is more yellow than gas and is more oily and smells different and more strong of oil. Fresh gas is more clear and the smell is familiar to most people with bikes or cars.
So after much cursing and throwing of tantrums, I eventually got the bike to go. Pulled the carb apart an cleaned it then put fresh gas in. Also adjusted the pilot screw, which seems to have solved the problem. Back on the road now.
Thanks again for all the help and input everyone. Wouldn't have Ben able to do it without you guys.
Fortunately, I'm adhering to a pretty strict, uh, drug, uh, regimen to keep my mind, you know, uh, limber.