Lean Pilot jet! 250 exc

[csdwarf]

Alright, so i have another thread and you guys have helped a lot getting my pilot jetting right (wont idle cold and surging at idle when warm)

I was just wondering, because me and a friend just drove to look at a cr250.


the guy ran 50:1 sythetic oil in the bike, its a 1998 cr 250. not racing, just trails.


my bike is being run a 32:1 sythetic.

I know, i know its actually a richer mixture, but wouldnt this mean less GAS? therefore a leaner burn?

would this maybe make sense why the jetting is so good, but its a little lean at idle?


thanks!

 

[RM_guy]

You are correct, more oil means less gas and a leaner fuel/air mixture. When I hear people saying that they want to fix a lean condition by adding more oil I cringe inside!

 

[whenfoxforks-ruled]

I run my 2000 CR250 and my 83 CR480 at 20:1 and do not foul plugs. A mechanically sound engine, jet it, and at least use the oil ratio the oem calls for in the manual. NEVER go by what the oil jug says, or use KTM to reference Japanese MX models for oil ratios. I run a heavier oil for more power and less vibration in the 250, then jetted it, the 480 calls for it. The key is properly jetting your sound bike.