KDXRIDER.NET

Hey guys,
I got a 2001 KDX220 at the end of summer last year, rode it a bit, but not much. During the winter I was looking thru forums and found out about the 220 piston failure. So I decided it was time to check it out (Seeing as the last owner said he didn't do a top end) So I pulled it apart and the piston looked good, but I decided while I was at it I would replace it with a Wiseco one just to be safe. Well I just got it back together (New piston, Bearing, Spark plug and Gaskets) And when I go to start it (choke on) it just starts revving way up, if I drop the choke it dies. Just wondering if anyone had this same problem (is it related to the new piston?) Heard some people say it could be a gasket leak, other said just a dirty carb or poor jetting.

I would check the carb slide first that it is not in backwards if that is even possible, I just remember reading about a similar issue regarding a Yamaha banshee and this was the issue. I assume you checked for a kinked cable, or other obstruction possibly interfering with the carbs ability to close, cable tension too tight ( no slack)?? good luck!!

As the last poster suggested go through your carb first, hopefully it's just gummed up and running lean, but if all is good there, I'd suspect a bad gasket seal. How did the cylinder base and intake surfaces look?

I bought A 97 Kx250 that had a complete rebuild with replated cylinder with the same problem. I got a great price on bike because of the problem. When I got bike home I started bike and sprayed engine with carb cleaner and found the leak around the reed gasket. The PO had used the long bolt where the short bolt went and got a false torque. Bike was fixed in 10 minutes. Hope this helps.

It's an air leak somewhere. Intake manifold, reed cage, and the base gasket are the most likely culprits.

Okay well it seems the reeds bolts weren't tight enough, pulled it apart and tightened them down, idles fine now.

Also thanks a lot guys, didn't think I would get tht many responses that fast, really is a great forum.

Okay, well I am back to some issues.
So the bike starts up (choke on) but when I take the choke off it dies, this happens when it is just started or warmed up.
Thinking it might be a jetting thing, but it did idle fine before. Just cleaned the carb out to so it isn't a clogged pilot jet.
The gas does leak out if I leave the fuel on, but I wasn't thinking that was part of the problem, could be now that I think about it.

Need to fix the float height and then see what's what.


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I believe the float height is fixed now.

Anyway so I decided to check my cylinder pressure today because I was curious, its only reading 85psi....So what are the normal things I should check?
Should be the ring gap and the head gasket right? Because from what I have seen it should be around 130-150...

time for new rings and head gasket.
if it still don't idle right then check your crank seals and then consider changing jets

So I pulled my head/cylinder today, What is the range for ring gap? Isn't it something like .10mm-.28mm? Mine is at .18mm
Head gasket didn't look bad, but I have one to replace it with, so we will see.
Also how much play is there supposed to be for the cylinder/crank rod?

Ring gap range is .15mm - .35mm. Service limit is .65mm

On rod there should be zero up and down play then measure the side clearance on the big end of the connecting rod on the opposite side of the flywheel. Specification for connecting rod big end side clearance is 0.40 - 0.50 mm.


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