How fast will an 86 250r go stock? How fast will it apx. go with a fmf pipe, twist throttle, new topend, 39mm carb?

 

Probably in the 70-72 range stock. As far as with the mods I couldn't tell you for sure. But to increase top speed, all you need is a gearing change.

 

the 86 model has a taller 6th gear than the rest of the years. it is slightly faster overall topend, but it may bog out without a little more juice. mine has a rad valve, boysen reeds, fmf pipe, and a uni air filter, stock carb (not sure what the jetting is since i bought it used from a guy in cali -runs fine here down in south, so i didnt change it) and it will hang right with a stock raptor.

with a bigger carb, yours should be a little faster than mine if the topend job was done right. but yeah if you want more topspeed go up one on the front or down a few on the back sprocket. i always thought the gearing of mine was good and wish the newer sport machines still offered 6 speed trannies.

 

I GPS'd mine at 70mph.

Mine has a Duncan FatBoy 2 exhaust, UNI filter, Boyesen Reeds, Shaved head, port and polished. Can't remember my gearing either, sorry.