I have a 2002 650 that I can not get to idle with the choke off
It runs ok as long as you leave the choke on
with the choke off you have to keep it above 20% throttle or it backfires and dies (runs ok with no choke above 20%)

it is also getting oil in the air filter box ??? (where is it coming from and how do I fix it)

thanks for any help !!!

 

could be one of a few things... I'll address the oil 1st... without knowing how long you've had the quad or it's condition... you'll get oil in the filter box, typically from one or more of 3 things.... if the engine is worn out, too much blow by will blow oil out of the crank case vent, & into the filterbox... if you fill the oil too full, it will also pump out of the vent & into the filter box... on some quads, that could be having the oil level at the top of the full mark... most people have started putting the oil level at 1/2 way between the add & full position on the dip stick... also if you do lots of WOT road riding, & occasionally if you reciently added one of the CDI's with less timing retard, & higher rev limit again, running WOT...

as far the gas thing... I actually had a piece of plastic from machining the gas tank... that cork screwed it's way into one of my jets... how it got past my filter & pump in the tank, I dunno ??? but the symtoms were the same as yours... BTW... anything plugging one of the jets would do the same thing... also if your motor were worn enough to have enough blow by to do the oil in the filter box thing, it may not run right with out the choke... also check your carb boots, if you are leaking air in, it would also have those symtoms...

 

ok I just went through and cleaned both carbs and all of the jets


the bike starts and runs ok @ idle with the choke on
with the choke off it dies @ idle
with the choke on and hitting the gas it revs a little and then falls on it face and dies (backfires through carbs)
if I turn the choke off while I am on the gas it back fires through the carbs)


any ideas ?

 

First thing ensure you got fresh gas, your fuel petcock is FULLY on, then with a low pressure air gun, blow out the brass looking vents by/near bottom of each velocity stack in your airbox

Next if problem does not go away take your choke cable and plungers out stretch the spring twice the original size reinstall and lube/grease the plungers and cable and re-assemble. If this fixes your problem order you a new cable/plungers for an 03 or 700. Alot of 02 had weak choke plunger springs/ the problem of sticking choke cables.

Enjoy that V-Twin Power

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