is a 2" diameter pipe from the head back, into a 2 disk insert to much flow for a 250cc? If so, what size would you recomend

 

Two or four stroke?

 

4 stroke

 

anyone?

 

Your about twice as big as you need to be and that will kill your bottom end off.
You need to be somewhere around an 1" to 1 1/8 ID. This depends on a lot of things though. You can also clog it up at the end to get a little bottom end preformance back; but this is not a good way to go if you ask me.
Take it out of the head at about the same size as the port.............maybe a bit bigger. Then about a foot down transition into about an 1/8" bigger and take it out the back and put a good flowing muff on it. This will get you close.

 

I hope I can find 1 1/8" pipe. With the inserts I wanna put in ( i wanna see if i can stay away from the coffee can type) It would have to have an ending diameter of 2" pipe. As I understand you only flow as much as your smallest pipe. So from the insert down to the tip I should be ok ( 2" inlet 3"+ outlet)

http://store.summitracing.com/partde...5&autoview=sku
If twos not enough I can just get the three disk. Find jet files and I should be on my way

 

I have a 250cc 4 stroke with a 2 1/2 pipe soming from the silencer.... Doesnt ruing anything for me! sounds good and is alot better than stock.. well Im not even close to stock my self.... so idk LOL