TheCp43racer

Member
Dec 17, 2013
4
0
Hey guys,
new here for a reason to do with my 1989 yz250 i rebuilt everything new crank seal new crank bearings all new seals oil seals and gaskets. New top end as we'll all honed out new rings and gaskets as we'll. however the bike will not seem to idle correctly and smokes a little bit more then it should it cannot be the crank seals or anything motor related my dad helped me to make sure nothing got messed up. The bike runs good but for some reason idles a little high and when u let off the accelerator it doesn't come down in rpm right away it takes about 7-8 seconds to completely come down. I have the air mixture screw all the way in on the carb as well as the throttle screw it has a new throttle cable and new clutch cable nothing is sticking. Could it be the jets? Wrong sizes or anything like that. Please tell me what you guys think the problem is I'm trying to get to the track over the Christmas break and want it resolved thanks hope to hear some good news. :coocoo:
 

IndyMX

Crash Test Dummy
~SPONSOR~
Jul 18, 2006
5,548
2
Amo, IN
I'd clean the carb properly and set the mixture screw according the the factory service manual as well as the idle set screw.

When I say clean it properly, I don't mean spraying it with carb cleaner. I mean tear it completely down, soak the parts in carb cleaner, then blow all of the passages and jets out with compressed air from multiple directions. Then just to be absolutely sure, spray carb cleaner into the passages and jets and blow them out again with compressed air.

Once you are absolutely certain that the carb is clean, put it back together according to the factory service manual, set everything to spec and use that as a baseline to tune the carb. Again going by the factory service manual recommendation for setup.

I'm guessing you don't have a factory service manual, so If I were you, I'd get one. Yamaha manuals are pretty easy to get ahold of if you are handy with Google.
 


Top Bottom