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Mikuni jet size scale to Keihin jet size scale

Posted: 02:03 am Jun 10 2023
by 85' kid
So I've got a Mikuni tmx 38mm carb on my 94 kx125 and it spits oil. I'm running a 50:1 mix and there is still oil just running down the silencer and dripping off onto the swingarm. I looked up stock jetting and it was 160 main jet and 45 pilot jet, and the stock carb was a Keihin. But the Mikuni has a 380 main and a 40 pilot. The pilot is normal but the main seems massive. Perhaps it is just a massive main jet thus the richness or is there a different jet scale that Mikuni uses as opposed to Keihin?

Re: Mikuni jet size scale to Keihin jet size scale

Posted: 12:35 pm Jun 11 2023
by KDXGarage
They do use a different numbering system.

If everything is mechanically sound, start at the pilot and air screw, then go up from there.