Nice site! Xr guy , just got a 90 kdx200

[El Gran Jamon]

With a CA plate! Seems a little down on power now, going thru carb, compression seems good..hope this is more powerful than my xr250r and possibly as good a general trail bike as an xr400?


Site even has kayaba fork stuff, nice. My bike came with what appear to be kx125 forks

..Jamon

[sarrant]

E-Series KDX that seems a little down on power (falls off on top)? Check for mangled KIPS subvalves. Actually, check them no matter what on this bike.

Steel replacements are available through BDK in the UK. Take a look at the E-Series subforum.

It should decisively outrun an XR250 power-wise.

[Julien D]

It is no slouch. You should find the problem pretty easily. Welcome to KDXRIDER, and congrats on your new ride!

[El Gran Jamon]

Tha ks, looks like the head has to come off at some point. I can do a top end on an xr no problem, but the Kips is a mystery to me. I downloaded the manual...will try the bike out this weekend.

I understand there's some cheap mods to get the hp above 35 hp? Something about new boysen reeds and a port job?

[david]

Welcome. My old 175 will out run my buddy's '85 XR250.

[El Gran Jamon]

Thanks,
I ride with guys on ,xr400's, xr650r's and ktm450exc's...mostly mountain trails , some open desert. We are all plated, run in the national parks, State parks, etc. I'll be laughing all the way to the bar after the ride on a plated 220lbs bike!

I'll be interested to see how well this runs.

[Julien D]

35hp is probably reasonable with pipe, airbox lid removed, carb mods, and proper jetting. Never had mine on a dyno so I can't say for sure what it's making, but that is basically my setup. If you can deal with the top end on your XR, the KDX will be a dream to work on. The KIPS are fairly simple once you have been around them once or twice. Just make sure you support that rod on the RH side of the engine when you loosen that LH threaded nut on top, or you will break it!

[El Gran Jamon]

Thanks,
Not sure o follow, but haven't read the diagram so I'm ignorant...

It's a horizontal shaft that will break because the weight of the head?

35 hp would be great. I think I'm around 20 just doing the highly calibrated butt o meter compared to my xr250r punched out to a xr280. .

[jjavaman]

No, it's a reverse threaded bolt on the kips that people break by turning it the wrong way! Enjoy the bike!!

[El Gran Jamon]

Ah, I see, the rod needs to be held from spinning (support) while using the reverse thread nut .

Ok. When I get time to tear into it beyond the carb, I understand people get some cheap reed and port job for 2,300 that wakes this thing up to 36 hp? Sounds like a winner to me make it a better desert bike as well!

[sarrant]

Ah, I see, the rod needs to be held from spinning (support) while using the reverse thread nut .

Ok. When I get time to tear into it beyond the carb, I understand people get some cheap reed and port job for 2,300 that wakes this thing up to 36 hp? Sounds like a winner to me make it a better desert bike as well!

You may find the bike's chassis may test your comfortable speed limits in the desert more than the engine. It really is built to excel in tight conditions.

[El Gran Jamon]

Truly,
But if it can handle 45-55mph off road without getting dangerously unsorted shout be fine! The kx forks seem about on par with xr400 stuff. I think I can handle a shim reshuffle if that's all it comes down to.

People seem happy with the power from the aftermarket reeds or kips valves and cylinder porting?

Might be all she needs!