'88 Kx 250

[76GMC1500]

Picked one of these up today for cheap for a friend, anything bad to look for? Anything good to say about this bike/engine?

Problems so far, swingarm bearings are shot, rear shock does no damping, frame has a repairable crack, swingarm has a repairable crack, power valves are very carboned up yet the cylinder has to be removed to clean them (pain in the butt), the bike starts and idles well after we cleaned the idle jet, but it revs up and stays reved up if you give it a little throttle (I have to bring it back down with the kill switch), the kick start gear is hit and miss (I'll be wearing boots and shin guards next time I try to start this bike), and the tank petcock is stiff. This is quite a list of problems, most of them will take time and not money to fix. I figure we'll have this bike running strong for another $150.

Could someone take a picture of the curved side of their Keihin PWK slide to show me what it is supposed to look like?

 

[MikeT]

First off, that is a good bike. I had one and loved it. The revving up is because there is a lean carburation issue. That might be in the form of jetting or an air leak. You need to fix that fast or you will have a cold seisure issue or a blown engine. Nice bike, you will like it.

How much did you get it for?

 

[76GMC1500]

We're not riding it until we get the lean issue fixed. I just have to track it down. We have pretty much ruled out air leaks. The pilot jet was plugged. We cleaned it out, but didn't really do any cleaning of the passages which will be next. I think the float level is low, but we haven't checked yet. Once we try all of this, if it still revs up, then I will get frustrated.

We got the bike for $600. Except for the problems listed above, the bike is pretty clean. It has good compression and once we cleaned out the pilot jet, it became easy to start.

 

[whenfoxforks-ruled]

You asked about the slide pics,If it looks worn I'd ditch it!, or do you think some hack has been at it? 96 bucks off bikebandit, ouch!

 

[76GMC1500]

It's got a weird circular groove at the bottom, I don't know if it's supposed to be there or not. I have no experience with a PWK, my bike is a PJ.

 

[76GMC1500]

Ok, I've got the bike running better now. The jets, needle, and slide are all stock except the main which is a 168 and a 172 is listed for the bike. The needle clip was in the 2nd from the top slot. I brought it down to the 4th from the top, 3rd from the top is stock. The bike started running better. I ran the air screw in to 1/2 turn out, 1.5 is stock, and the bike was running pretty good. I haven't had a chance to ride it yet, but I feel like the bike is going to be fouling plugs in this trim. A 52 slow jet is stock and that is what the bike has. Right now, the bike is inconsistent. Sometimes, it will stay at a high idle after revving, sometimes it will be perfect, sometimes it sounds like it's loading up and about to die out. If I open up the pilot screw a little more, it returns to a higher idle, but is more consistent. At least it doesn't sit near the rev limiter after revving.

I think I need to richen up the slow jet which will let me open up the pilot screw a little more. I was thinking a 56 or 58. I suggested the owner also get the 172 main jet, but would that really be necessary if we enriched the slow jet? Am I on the right path here? This is the first time I've needed to tune a carb on a 2-stroke.