XR600R carb issues

I have an '88 XR600R with CR500 forks, a supertrap/jets, baja street kit, and I love it!. The only issue is, it seems to have a worn out carb in that, as vacume builds, it gets sticky - like the slide has slop in it. Has anybody seen this before, could it be some venting issue ?

If the carb is shot, I guess I am looking for a good used one, or any suggested upgrades etc.

On a different note, can anyone tell me how much better a KTM 450 would be than a XR400 for over all fun, low maintenance, and of course ride comparison.

The slide is free when the motor is off? Its unusual to wear out a carburetor...

Have you pulled the slide to see if its got a ridge or something worn in it?

Dropping to a 400 may bug you since youre used to the thump of the 600, but its a fun little bike for a lot of different things. Never ridden a KTM, so I dont know...

I have taken the carb apart, cleaned the bore with 1200 grit - very smooth, throttle is like butter when not running. I am kinda baffled.

if you scrap your carb i would be interested in the choke plate.


If you're talking about chopping the throttle going into a corner and then having to twist real hard and getting a jump when the slide releases coming out,it's a know problem with stock carbs. There was a thread that suggested drilling a small hole in the slide to relieve vaccum. I had one that was really irritating. I ended up putting a Mikuni on one and a Edlebrock on the other. No more problem

The 600 engine has quite a bit of intake manifold vacuum when the throttle is closed on deceleration. The high vacuum pulls the slide against the slide bore wall and causes the slide to hang up. The situation worsens as the clearance between the slide and wall increases due to wear. Addition of a small amount of two stroke oil to the gas will alleviate the situation somewhat. As daddyk points out, the Mikuni or Edelbrock carb will eliminate the problem completely plus provide easier starting hot, cold and when you drop the bike. Performance and fuel mileage are also improved significantly.

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