Fuel mix and carb jetting

[professortp]

I just redid the the top end of my 83 250. Replated cylinder, new piston, rings, gaskets, new Uni air filter, and so forth. The Kawasaki shop manual I have for the 83 says use a 20:1 fuel mix ratio. There wasn't any info on what stock carb jetting should be and it seems to be running extremely rich. I live at approximately 1000 feet above sea level. I'm using Klotz Be-Nol at the recommended 20:1 for my fuel mix at the advice of my local Kaw dealer as opposed to a synthetic oil. Does anyone in the group have good info on carb jetting, adjustments, settings, and best oil for clean running and dependability, especially a new cylinder? Thanks !

[KDXGarage]

I just redid the the top end of my 83 250. Replated cylinder, new piston, rings, gaskets, new Uni air filter, and so forth. The Kawasaki shop manual I have for the 83 says use a 20:1 fuel mix ratio. There wasn't any info on what stock carb jetting should be and it seems to be running extremely rich. I live at approximately 1000 feet above sea level. I'm using Klotz Be-Nol at the recommended 20:1 for my fuel mix at the advice of my local Kaw dealer as opposed to a synthetic oil. Does anyone in the group have good info on carb jetting, adjustments, settings, and best oil for clean running and dependability, especially a new cylinder? Thanks !

Did the dealer recommend 20:1 or the Klotz?

I am thinking 40:1. Heck, although I am slow, I ran my 2005 KX250 at 40:1 when I was racing MX a few years ago.

20:1 was cool back in 1982 when that manual was made, but oils have become better. Later KDX's came with a factory recommendation of 32:1.

[kvkdx]

I run 50:1 with amsoil interceptor or Motul 710 sometimes, and both work great at 50:1, I think the interceptor is a little more clean and less spooge than motul 710, but its very small

[bufftester]

Keep in mind that although oils have gotten better, part of the reason the manual says 20:1 is because it's an air cooled bike and they run a bit hotter than later watercooled motors. They also typically run much richer. That year got the 36mm Mikuni, IIRC and my handwriting is bad so take it with a grain of salt, MJ155 PJ35 sounds like a good starting point. Process is the same as for the later Keheins, adjust the air screw at idle to determine pilot, then plug chops for MJ.

[professortp]

My thanks to everyone that replied ! I'll try to determine my pilot and main jet sizes and experiment with mix ratio. Happy trails !