3AJ RUNNING TOO RICH?
 

HI everyone, Having just rebuilt my 3aj engine,ive found that when i replaced the air filter the bike backfires and then splutters to a halt.when i remove the filter it runs fine,but having just rebuilt it i dont want it running without an air filter. the manual states that the pilot air screw is fixed behind a blind housing and removal is not recommended!! any sugestions please. p.s can anyone recommend a good air filter for a 3aj? thanks T.

I think you just answered your own question there big t. You've got the wrong type of air filter fitted, it's to dence. give your local yam shop a call and they'll point you in the right direction, Haven't bought my new one yet so can't help. i am getting a foam one though so i can clean it out and re-use it.

Did you put in a new standard one, which is oiled foam. If so, you must have oiled it yourself and put in far too much oil.
Soaking it in oil you should squeeze it out till there is no oil coming from the foam anymore.

The pilot air screw: with carb wear you want a ricger idle mixture. Just remove the little alu cover plate and screw out for richer mix, screw in for leaner mix. Don't brun your fingers, I find a little flat screwdriver bit the best tool not having an around-the-corner screwdriver.

BTW: ar eyou sure that after your overhaul sufficient petrol reached the float chamber? Check by opening the little drain plug on the bottom of the float bowl. If petrol runs out you are OK.

Auke

hi, the previous owner had a home made filter in there, just a piece of foam cable tied onto the filter housing! i replaced the inlet rubbers and was thinking if they had been leaking, had the previous owner richened the mixture to componsate. thanks for the replies,i will try some experimenting. T.