KTM MIKUNI JET BLOCK GASKET FAILURE

George stewart

Well-known member
JD jetting has a improved gasket . I bought a used carb on the ftr forum to bore out The guy gave me box full of jets he had tried . I was not aware there was a jet block gasket found out on thumper talk . This carb had oring leakage and a failed jet block gasket no wonder the guy had a box full jets, needles, nozzels ktm should have a carb recall and mikuni fix the gas leaks it is a fire hazard these are small cheap parts . My 250xc has picked up a after bang in the exhaust it still runs just not as good as it did. I bet it has a gasket broken in the jet block. I will order new gaskets and orings tomorrow .Please make sure you cut the petcock off hate to burn your house or camper or you
 

Chris Holme

Well-known member
A lot of people pull that carb off and throw it in the trash. Then replace it with a lectron,smart carb, or a keihin pwk.
 

George stewart

Well-known member
Chris I have a keihin , mikuni my son has the lectron never tried the smart carb of these three i like the way the stock carb runs. Iam going
to bore the extra mikuni out .080 I have a lot jets to play with that came with it. Everybody cannot throw a $300 carb away . Maybe this post will help some people .The jd parts are only about ten bucks. goracing
 

Michael Rewis

NOMAD RACING
A lot of people pull that carb off and throw it in the trash. Then replace it with a lectron,smart carb, or a keihin pwk.
And they are not very intelligent people.

It is a relatively simple fix for $7.95 plus shipping and once done, the carb works excellent, perhaps even better than the Smartcarb, Electron and Keihin.

Following the herd's advice will usually get you somewhere, though not likely where you WANT to be.
 

George stewart

Well-known member
The jet block if this is the proper name is located under the throttle slide to remove it two small screws under the float .Also be sure to replace the oring on the float valve seat it tends to be to small jd jetting carries a kit that cures two problems gas leaking and jetting problems with this gasket . This problem may only be on 17-18 ktm-hus 250 300 jd jetting could tell you. my bike runs great now. No blubbering or after bang.Kit is dirt cheap bikr
 

Dr! Still Bill

Administrator
Moderator
Club Representative
Area Director
Speaking of jet block gasket, I had a Keihin with one that went bad also. Ended-up replacing carb with a very good counterfeit one from eBay. Did not know it was counterfeit until after I purchased it. Like I said, a very good knock-off. The $40 price should have been a tip-off. This particular one was for a KDX.
 
Top