I have a stock '86 250R with a FMF Fatty pipe and Powercore II silencer, but I want more bottom end. What is a cheap bolt on product for this?

 

A big bore kit is the best way to get more bottom end but its not cheap. Otherwise a woods pipe.

 

THE BEST MODIFICATION is the pipe--for LOWEND power you need the Paul Turner Type 6. It makes MORE lowend power than the stock pipe! Your FMF has an emphasis on MIDRANGE power. Just thought you may want to know. Another thing, keep the stock 34mm carb, going bigger makes lowend power suffer.

 

Would a set of reeds help any?

 

The FMF Ram Valve is rumored to help lowend more than the others(Delta or RAD Valve) however the FMF reeds CHIP more than the other brands. A set of Boyesen Power Reeds or Pro Series(carbon fiber) WILL help throttle response in comparison to the stock reeds. Another thing you can do is add a Reed Spacer. It shifts the power lower and improves torque. Next question?

 

How much does a reed spacer go for?

 

My friend and I just put the same pipe on his 87R and we lost the bottom too. Then we put the ram valve on. It did not help. It was a pain to ride in the woods. So we put the pipe on the shelf. Went back to the stock head pipe with the FMF tip. Put in a reed spacer and the ram valve back in. That seemed to work the best. So we have another after market lawn orniment. Live and learn.

 

The right pipe can definitely add low end power. We tried the reed spacer with the FMF Ram Valve & it sucked. The reed spacer with the Boysen Rad Valve seemed to improve the low to mid power. A 38 Keihn AirStriker will DEFINITELY improve the low end & throttle response. Depending on where you are riding, you might consider dropping a tooth off the front sproket.

 

Bigger carbs and reed spacers do not help bottom end. You need to raise the compression of the engine. The cheapest way to do that is to use a CR250 head gasket. Otherwise get your stock head modified or buy a Coolhead. Using 12/38 gears helps a lot as well.

 

I tend to agree with Raychalp. I had forgotten one of the cheapest mods - raise the compression. You can buy a Weisco piston that will raise the compression, mill the head, use a thinner head gasket, or use a cool head & choose the compression you want. Just use caution, too much compression requires higher octane gas than you can buy at the local gas station. Too low on the octane & you will burn a piston.