Poor top end

Seized I presume?

I'm wondering about doing 'everything over' including a sleeve. The cylinder was over-bored, sleeved, then recoated?

That's counterproductive. Why not make it a big bore (225cc)?

All the items you mention NOTwithstanding (meaning, they aren't part of the problem...sleeves/port matching and stuff), did you arrive at the 155 via plug chop tests? I could jet my bike to do the exact same thing...been there during jetting sequences.

That said, a kdx (oem port timing/compression and such) does kind of 'top-out'. It doesn't scream like most track bikes. You don't mention if maybe you're used to some other type of bike.

THAT said, the aforementioned doesn't happen on the last 1/4 throttle. Just at the top.

Any leak at the head gasket is obviously bad. What you see may not be the only problem (it's bad enough!).

I don't suppose 'surface flat' means a piece of wet-n-dry on top of your table saw? I recall that 'surface flat' method to give mr. gorr some kinda' nightmare! ;)

So:
1. A '95 should not have been sleeved to get back to 200cc.
If it WAS sleeved..what piston did you use? If it's NOT oem sized, your compression went WAY up and the head has to be machined to bring it back down, or you need to run a high octane fuel and jet to fit.

2. Fix the leak.
Was a new gasket used? If RE-used, did you use a spray on sealer? Should have.

3. Jet via testing...not what anyone said, or what you've read.

This 'sleeve' thing is a big question............

At the very least you need a new head gasket and ensure the head is tightened to the proper torque using the pattern described in the manual. If coolant keeps leaking from between the cylinder and head you have a bigger problem on your hands and need to do some digging around to ID the problem.

If you followed the manual when reinstalling the KIOS valves its possible you installed the subport valves in reverse. Many factory shop manuals wrongly identify the sub port valves. You can check the JustKDX web page in the Tech Tips section for a correction to the manual.

David

^^ This could very well mean your running lean. If your pretty sure the KIPS was reassembled corrrectly stick a bigger jet in there and see if the problem goes away--then you can fine tune for max power/response/desired 'hit'. If it doesn't go away, then your problem is probably elsewhere...

re:'couldn't see anything on the new plug..'

Looking with what? Where? If you're jetted PERFECTLY and you yank a test plug and merely 'look' at it, you will see exactly what you say... nothing.


Check this:

http://www.dirtrider.net/forums3/showthread.php?s=&threadid=60392&perpage=20&display=&pagenumber=1

...for information on WHAT you're looking for and HOW to look for it.