My mother has a 02' scrambler 400 she bought her a nickle plated hot seat generation 2 i think header and fmf silencer. I installed both of them on there and ran it with out messing with the jets. It didn't have any power at all so i went with the 250 main jet, 240 is stock, and it was a little better. When u take off it has no power unless u hold the brake in, then it will ride a wheelie, and once u get goin the power just starts goin away till u hit about 50 then the engine revs up real high and the power kicks in again. I can't figure out the problem. It seems to only do this once the exhaust gets warmed up. Cuz u can take off on it after it has sat there a while and it will run perfect untill about the 2nd or third run. Any help would be nice, thanx

 

Did you put in a clutch Kit,Alway adjust clutching when messing with power adds so it is clutched to the proper power ban.
You said no power unless you brake torque it, You are manualy changing the clutching,(Belt slipage)I think you will need to call Hot Seat and get aclutch kit to go with the Pipe.

You also may need to go up to the 260 jet. have you looked at the plug
Black= rich
Brown= PERFECT
WHITE= lean

Also note= The hot seat Pipe is common to lose a little on the bottom but the midrange and highend gains are great. Are you running 1,2,or3 of the adj shims in the Exhaust flange?, The more shims you add the better the low end will be,with some loss on top.

Hope this helps

 

Bubba is right, when you changed your pipe you changed the rpm range in which your engine operates. You will need the proper clutching to operate in those RPMs. Get hotseats clutch kit, they know the best clutching for their pipe. Also, I would bet your on the lean side, go to a 260 or 270. Its always better to be rich than lean. Start higher and work your way down.

 

Like the others said, give Hot Seat a call, Rob's a good guy. The Hot Seat pipe does have quite the flat spot initially, you can work most of it out with clutching, but until you go the race-port route from HPD, you'll still have some hesitations. The trail bonus of the pipe and properly tuned clutch will give you the YAHOO'S!!!


Ken

 

you should be running 270 main jet with the gen 2 pipe,get a new performance clutch kit to your type of riding,also this pipe is tuneable for more bottom or top end power with shims,the more you get shims the more you'll get bottom end torque if you throw all the shims out you'll have better top end.always check spark plug color when first trying a new pipe at ALL throttle position,you might get a new k&n air filter cauz with the new pipe the motor need MORE air,that maybe the bogging your engine is having...