My friend has an '87 250X w/ these mods.- Wiseco pro-lite[.20 over],ported head,heavy duty valves/springs,W.B. [race?]cam,Mikuni flatslide[mm?],K&N filter,DG Chromepower ex.[full],Stock gearing,stock tires.Jetting is very close. This machine does not run as well as I think it should(perf.).I have a 350x (stock) and I don't believe the 250 is even close,even with these mods. We have not actually raced them, but I have ridden both.Does anyone have any Ideas on getting more power from this setup? No more money to spend! THANKS!

 

P.S. Also has ROOST BOOST ignition! Stock CDI box. Holes in Airbox lid. We have run w/all pipe discs and none. Not much diff. Jetted to run all.

 

Did he just put the cam in, or has it been used for a while?

 

The cam has been in for a while. I will guess 20 hrs. on all mods.

 

I don't think that with the mods you have listed, the 250x will be close to the 350x in power. If I remember right, a stock 250x puts out about 12hp at the rear wheels. The cam, piston and pipe maybe add 5-6 real world hp. The 350x puts out about 22hp or more in stock form. If you still think there is something wrong with the 250x maybe start with a compression check(might have a ring that was bent or something), check to make sure that the cam timing marks are aligned(could be a tooth off). This is probably a dumb idea, but, make sure the clutch isn't slipping. And last but not least, check the valve clearance(if this was set wrong, it could be holding a valve open slightly when it shouldn't be).

Good luck!

 

12hp?

they put out about 15 or 16 stock...with all those mods to me he should be putting out about in the mid to low 20s.

5 or 6 for piston cam and pipe, plus porting and a vavle job..thats another 2 or 3...