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KDX200 KIPS question

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I have a 97 KDX200, new to me. Bike starts and runs, idles fine. Only has a short burst of power off the bottom, then flattens out quickly, seems weak. PO rebuilt the motor because it was weak and thought this would help, bored and replated cylinder, new Wiseco piston and cleaned the power valve. I took the clutch cover off and checked the governor assembly, all correct there, proper sequence of washers and bearings and spacer, seemed fine. Linkages inside the cylinder seemed timed correctly, could see punch marks and slots on rods, could not see the paint mark on the gear on the outside that is supposed to be timed to the rotating shaft with gear on top. Question: How freely should the mechanism work if its not connected to the timing rod?

While I had the cover off, I also had the expansion chamber off, I rotated the gear by hand to see if the valves were rotating on the sides of the port and the top one sliding back and forth. They all seemed correct, but seemed like it took a lot of travel to move and had some drag. Just seemed like they had a rubber o-ring dragging them or something. So I put it all back together for a run and removed the screw cover on the left side and put a wrench on the nut and ran the motor while helping the valve open by hand. It seemed like a couple of times that as I gave throttle, it wanted to rev up quicker if I helped it along. Will it loosen up as time goes on or what? Is this really a power valve issue, or is it possibly a carb related issue? It seems to run fat after the power level drops off. It burbles some. Main jet was a 140, pilot was a 48.

Comments??

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Talked it over with a buddy yesterday, we're thinking its the crank seals (bearings) since the PO did not rebuild the bottom end. It has good compression when its coming up on TDC but weak when she's down low.

Comments??

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Hey, Dude. Lemme ride yur bike. I'll tell what I think. :p

This would have been funnier under a fake ID. :ride:

The stock main jet is listed as a 160 on the parts diagram. Is 140 a typo??

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140 is way too lean, try a 152-155 and retest, before you go throwing even more money at it, try the simple stuff

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Your power valve shouldn't really have any drag when you move it by hand, especially if its not connected to the timing rod. It should feel smooth. Maybe your powervalve needs a good cleaning, it could be hanging up, or not fully opening or closing.

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KDX, I'm always serious man!!!! If you want to ride it, be my guest. I was hoping it would be something simple, but you never know.

Sean, yes that's what it says on the number on the jet. I couldn't believe it either, so I compared it to my jet gauges, and it was 140.

This is the first 2T I've owned with a power valve, so that tells you I've been out of them for a while. Last one I had was an IT490 and it would take your arms off in any gear.

The mechanism moves, just takes quite a bit of torque to move it. I'm thinking I need to pull it down and take a look, just don't know what to look for.

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