What exactly will a 38mm carb do to a 86 250r? Is there such a thing as too big or can you always go bigger? It has other mods.

 

Sparkster,

Intake is directly proportional to exhaust... What else have you done to the wheeler??? Do you have a stock pipe and silencer??? Stock porting? Stock intake manifold, reed cage, and reeds??? Air filter????

It really all depends... If you took a totally stock machine and only bumped up the size of the carb by 4mm, I personally think the gains would be limited. You would see something, but not what I think you are expecting.

Hope this helps.

 

What i have generally hears about carbs is that the bigger the size of it, the better it is for top end power; the smaller the size, the better it is for low end power.

 

It has fmf pipe and muffler, is ported and polished, and has a K&N air filter. Not sure how much it is ported.

 

If you already have port work and air(k/n)the carb will make a difference you need a good pipe too and your choice of pipe will depend on where you want your power to be (LOW-MID-HIGH) JUST A WARNING IF you haven't had much experience with jetting a carb sometime ot can be a real pain. good aftermarket reed cage will make a big dirrence too.. hope this helps