Loss of top end 99 220

[GabeM]

I just replaced the piston on my son's 99 220 and cleaned the powervalve and now the top end is gone.
We bought him an FMF Knarly woods pipe and powercore-II silencer and re-jetted at Christmas time. the bike really came alive on top. easy wheelies in 3rd and 4th gear. But now that he was reving the bike a lot more I decided to replace the stock piston with a wiseco. I took apart the power valve (which I had done before on my old 200) and cleaned it, there was very little carbon on the exhaust slide, and the valve was operating smothly before.
After re-assembly, the valve worked great manually and you could see it turn thru the side inspection cover. But now he has no top end. I checked the jets to make sure there was nothing clogging them, and the main shaft still turns when you rev the bike up.
Could one of the side valves have broke just below the gear? I re-assembled them correctly paying special attention to the notches and detents on the shafts and the gears. Like I said, I've done this on my other bike and it's no big deal to do it.

Thanks
Gabe

 

[adam728]

It is possible that one of the side drums could have broken, but it is more likely that they are just out of alignment.

I have found it easiest to assemble the power valve system with the cylinder off the bike, then operate it by hand and watch how the drums open the transfers through the main exhaust port. It's very easy to have the gears from the sliding rack to the drums off one tooth, and then you will not have the transfer ports open fully (or possibly even open at all).

 

[GabeM]

Thanks, I did assemble it with the head off, and you are right that you can see the ports open when operating the valve.
A friend of mine who had a 91 KDX told me one of his valves was broken when he got the bike. But my son's bike has very few hours on it.
I wonder if I take off the KIPPS cover (left side of head) if I can see the left valve? and would it operate without the cover on if I start the engine?

 

[adam728]

Your best bet would be to remove the exhaust, remove the gear from the actuator shaft, then turn the main powervalve shaft by hand and look to see how it all operates. If it moves by hand it will move when running.

If you take the side cover off you can't really see anything except a small square hole into the cylinder.

 

[GabeM]

thanks adam728, I'll do that and report back here, just didn't want to take the head off, not that that's a big deal either.

 

[adam728]

You could possibly do it all with the head in place. If one of the barrels is not in the proper place you can pull the rack gear, then use a screw driver to push on the flat of the barrel in the direction it needs to go, then put the rack back in and try it again.

How to do that on the bike with the frame in the way is what will be hard!

 

[GabeM]

a small mirror and patience will do it, I have both

 

[Green Hornet]

You DID HOLD THE ACUATOR SHAFT W/A WRENCH, Right??? If not your problem is your broke the Govenor located in the clutch case

 

[steve.emma]

hornet is right, its real easy to break the shaft that comes up from the governer which will prevent the kips from moving.
you could try remove the right side kips cover then put the pipe back on and start the bike, rev the motor and see if the shaft turns or not.
a lot of people brake the shaft by not using a spanner to hold it when undoing the nut at the top. there are 2 flat spots on the shaft under the rubber cover for this purpose.

 

[GabeM]

thanks for the heads up guys, but I did hold it with a wrench. Learned this the hard way on my old 200 the first time I did it.
FYI, the shaft turns because you can see it thru the inspection cover on the left side of the engine when revving it(large cap w/ screwdriver slot).

 

[paab]

valves must be out of position then. No other explanation if you've checked the basics: reeds, plug, airbox, carb etc.

 

[GabeM]

OK guys, sorry for not posting what I did.
We tooke the head off and the valves were in the right position, from the top, the left valve has a relief ground on 2-teeth, and this lines up with the groove on the shaft.
On the right valve, the teeth also have the relief ground, but no groove on the shaft?? What does this mean?
I lined up the valve at a mirror of the one on the left and put it together. No change at all, still drops off on top like it's starving for gas, if you stay on the throttle, it slowly comes up to RPM.

HELP please

 

[ridejunky]

I don't mean for this to sound bad, but Ill ask anyway. Did you put the piston in with the arrow forward?

 

[krazyinski]

some times its just murphy's law in effect. check your ignition,this may not be your case but maybe all the focas on the KIPs has put the blinders on. I put a set of reeds and a new rear tire on 130x18 a mistaken order I said oh well, put it on. tested the bike out around the yard worked good. 2 hour drive with a riding buddy to the trails. I left the gas on none dripped out the overflow, I tried to start the bike at the trail head and she fouled a plug. never done that before! mm?? MYwork? are the reeds in corect?? I replaced the fouled NGK B8IEX with a NEW BR8ES. she fires up and off I go!! after 10 miles the bike is sluggish lacks top end man I am riding with the throttle wide open ! I figure its that 130 on the rear stealing all my power. I spend half the day rejetting and jacking with the bike just about to give up and figure it must be time for a topend job when my bud say's screw the old plug in (fouled NGKB8IEX). BBBAMMMM!!!!!!! just like that she came back alive. son of $%^$%$& I spend all day ??? and OH well I guess you get my POINT.