Mikuni carb...aaaarrrgh

[karmobRob]

Ihave a Sukuki 300 king Quad and cant get it to run good.Pulled carb,checked all bits,clean as.Needle/seat bang on.Idle mix 1.5 turns out to 2.5 turns.At idle,slide will slowly lift and idles up.OK if I stick finger in intake and hold.Any ideas appreciated.

[riffer]

My RF has Mikunis. When the mileage gets up the slide (which is plastic) wears at the edges creating a parallelogram shape. This has the effect of causing the slide to wobble a bit, causing the emulsion jet needle to wobble. Also it wears the emulsion jet.

Check for:

a) parallelogram type wear in the slide
b) ovalisation of the emulsion jet.
c) take the diaphragm out and hold it up to the sun. Are there any pinholes or slight tears?

[Grumph]

Look for a vacuum leak between carb and head - sounds like it's leaning out at high vacuum (idle) hence the revs go up.

[karmobRob]

Thanks guys,I'll have a dig.

[Wannabiker]

Make sure you re-fitted the diaphram spring!! Wouldnt be the first time someone has left this piece out when putting the carb back together.

[lone_slayer]

Thanks guys,I'll have a dig.

Howd you go with ya carbs?

[karmobRob]

Got it better, but still on the backburner.