My 1996 yamaha yzf600r will attempt to run if i hold my hand over carbs i have took the bowls off and the pilot jets and needles and cleaned them really good and if i dont hold my hand over them and turn it over it will attempt to crank but all it does is backfire and i have no clue what to do i need help...

SOURCE: 2005 yamaha yzf 250-unstable idle

I had the same problem, Turns out that my shims were finished, replace the chims and check clearences.

SOURCE: Cleaning Carb Jets

not to a trained ear also go by rpm and spark plug color

NOTE: use copper wire to clean jets, sync is just thottles are same position as all carb's just leave them adjustments alone will be fine if are out use a 1/8 drill an place in between piston/butterfly to carb bore to sync/calibrate

better use a manometer for adjusting screws

depends on condition of org parts

worn = richer running

new = lean an clean

also if changed the exhaust system need to
re-calibrate carbs for max performance

SOURCE: I hear talk of an air jet for the mukuni bs34

I believe they are referring to the nozzle the needle goes into. A venturi effect is created by the position of the nozzle in the throat of the carb. The nozzle has holes in it and the fuel is sucked through the main jet and out the holes to mix with the rushing air as the needle raises. Beyond that I haven't got a clue.

Please rate this solution. Thanks!

SOURCE: what is a good carb set up on a 2005 yz125 with

this will depend on what gas oil mixture you have

check this topic out.

http://www.dirtrider.net/forums3/showthread.php?threadid=117838

http://forums.dirtrider.com/70/7640379/yamaha-dirt-bikes/yz125-carb-settings/index.html

regards,

voodoo

gavin jones

• 1508 Answers
• Posted on Feb 22, 2011

SOURCE: my 2005 yz250f will not idle and backfires on

check valve clearances first. will cause backfire and ide probs
a leaking exhaust gasket or low ignition voltage will cause backfire