carbs

[Rodimus Prime]

dirty carbs can cause multitude of problems

i will list some of the things most common problems and fixes to the carbs

walbro carb

most common flooding or incorrect running is that rebuild kit includes two gaskets that go under circuit plate plus the reed valve.. without 2 gaskets needle settings are wrong.


mikuni carbs

air screw 1-1/2 to 1-1/4 out if you need to turn more or less for idle change pilot jet one size

choke adjustment
factory had nice but useless plastic measurement guides. best method is to make sure choke plunger is clean and smooth as well as bore. back off adjuster to make sure plunger is in bottom. next turn adjuster till you have 1/8-1/16 slack in cable before choke leaves seat.. test on cable or lever.

throttle valve
common problem on this is marked up screws and that people forget to put back in the plastic washer that goes between needle clip and throttle valve.

needle clip position should be middle. one up or down usually means wrong main jet

throttle valve slack is adjusted first. with carb off adjust cable so that valve just clears the opening on engine side.

duals both valves should open at same time.. i use finger feel or guage.

common problem on mikunis that have sat for any lenght of time over 3 months is plugged pilot jets. mains are usually obvious if plugged.

inlet needle and seats do wear out change if you have common flooding problem otherwise just clean and reinstall.

float height is parrallel to carb body.

thottle valve adjustment cold.. back out screw reach in carb and feel throttle valve turn in screw until it just touches valve then turn in additional 3 turns.


mikuni butterfly

common problem is tarnished needs and seats use Qtip cotton swab with carb lceaner to make sure they are clean. adjustment needles can be redressed with a drill and file or metal lathe.

although not original to jd

tilliston

there is orings on outside of needles replace these. under the caps is check balls and seats replace if carb will not run properly(note skidoo dealers can get replacement caps and balls.) flat edge over carb body main needle adjustment is 0.020

keign...i spelt that wrong im sure

the tube on side is guage with fuel halfway in tube carb is set correctly. if not start playing with jets.


other carbs

bendix carb

when they work they work great engine must be near perfect and parts are not available. common problem is main needle and seat going bad. also there was in later years a replacement from bendix for tube that was above throttle bore