Jetting On An Rm250 HELLLPPP!?!

[TheNewOldSchool]

I have a 1991 RM250 with an FMF Fatty pipe and Boysen Pro Series reeds. These are both fairly standard mods for a two stroke. So does anyone have any recommendations for what size jet to use, air screw adjustment, etc? (on a Kehin carb) I went on the FMF website and they have the jetting specs for just their pipe on an otherwise stock motor, but the reeds supposedly run leaner on the bottom and richer on the top compared to stock reeds. I will also be riding mostly in low altitude/desert. Any help/tips for my combo???? Thanks Alot.

 

[2 strokes for life]

No one can tell you the absolute jetting you need. But what you can do is run it with what you have and work your way up.

 

[Morvo]

Or, you could visit the FMF website and look at their recommended jetting guide?

 

[TonyJeske]

What jets/needle are currently in it? My guess is that it is too rich, but since your riding desert your going to want to stay a little fat. The specs that you'll get from FMF will only be general, they wont fit your riding style. They might help for a base line setting, but if you are going to be jetting often you should be familiar with what is in your motorcycle.

 

[CRazy250]

reed tend to make it run rich so drop in slightly richer jets.