Jun 13, 2001
'91 kdx200 power boost?

My son (13) has just purchased "91 kdx200. We are purchasing an FMF Fatty pipe new reeds ect.. . Can anyone let me know if the've tried the Fatty and what reeds you've used. Also we will be buying clutch plates. What has worked for you? We're looking for Low end power, we are single track riders that ride pretty aggressive. Also we are looking for a resettable trip odometer to fit the bike.

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dirt bike dave

Sponsoring Member
May 3, 2000
The FMF pipe, an aftermarket silencer and Boyesen Reeds are a nice improvement to the bike, but IMO the two highest priority items are re-jetting the carb and fixing the forks (stiffer springs & revalving) if those two things haven't been done already.

You might also consider a steering damper and a 12t front sprocket. The dampers are expensive but they sure add to the fun factor in the woods and you can usually transfer it to the next bike.


Aug 10, 2001
Trip odometer

Not sure how this would hold up on a dirtbike (haven't tried it on mine yet), but my dad adapted one of those bicycle computers (like you put on a moutain bike & such) onto his old Norton. It stores all the trip info you need, and they can be found relatively cheap. However, I believe the speedometer function is limited to around 60 MPH.:D If i ever get around to trying one on my dirtbike, I'll post the results.


Dec 13, 2000
I had a 91 KDX200 and it was one of the best bikes I've owned. I put a FMF pipe and a Answer spark arrestor on it, I would recommend this to any KDX rider's out there, ( FMF pipe and any of the high end spark arrestor's like FMF, Pro Curcit, Acebis, Answer will do, the FMF seems to be the favorite) I never did do the reed's but that should be done esp. if you want bottom end. Like posted above get the suspension set up, very important and dont forget to have fun !! Change the handlebars too if the stock bars are still on the bike.

Canadian Dave

Super Power AssClown
Apr 28, 1999
The FMF pipe works well on 89 to 94 KDXs and I'm sure you'll like the results. My personal favorite is a modified stock pipe. Removing the inner most lining from the body of the pipe is an excellent improvement and won't cost you a cent, well ok some mig/tig wire and a little time. If you have access to brazing equipment, a tig or mig welder I'd highly recommend it. You can find instruction on the JustKDX home page. Follow the link below.

Boyesen Power reeds and your choice of aftermarket silencer will work well in your KDX.

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