Author Topic: 1990 kx500 power valve issue  (Read 7917 times)

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Offline kawirider1469

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1990 kx500 power valve issue
« on: May 03, 2015, 11:57:52 AM »
So I picked up a 1990 kx500 for 800 bucks. Not the prettiest bike but runs decent. Decided to put new clutches in today and replace cylinder head gasket. Took power valve off and clutch cover and thoroughly cleaned everything. Clutch oil was like milk and clutch plates pretty much fell apart. Installed new clutches and changed head gasket. Put everything back together and now it acts like it has no power. Hits normal in bottom end and then loses power... it will not clear out and hit. Question is...is there something I could have done wrong reinstalling the power valve? Any advice would be appreciated.

Offline 81cr450

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Re: 1990 kx500 power valve issue
« Reply #1 on: May 03, 2015, 12:19:34 PM »
My guess would be the 10mm nut on the actuator arm when you tighten it you can goof up the opperation. You did load the powervalve governor in the cover when you put it on , right?
if I only had a pair, I could actually ride this thing

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Offline kawirider1469

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Re: 1990 kx500 power valve issue
« Reply #2 on: May 03, 2015, 01:05:36 PM »
What do u mean by "load up" I've looked everywhere for info on how to do the power valve install and have had no luck

Offline dave916

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Re: 1990 kx500 power valve issue
« Reply #3 on: May 03, 2015, 09:56:36 PM »
sounds like u need water pump seal if the oil is milky [unless it was driven into a deep river :-)  }

I think by load up 81cr480 means did u fit it correctly. [sounds like something is gone wrong in there}
power valve rod has to move out when engine is reved high


if the rod has been moved manualy {by hand} is is possible for the needle of the kipps bearings to fall apart
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Offline kawirider1469

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Re: 1990 kx500 power valve issue
« Reply #4 on: May 04, 2015, 12:21:05 AM »
I didn't take the head off so all I really took off was the 10mm bolt that holds the actuator arm on. I dis clean inside of clutch cover with brake keen and also put a lil oil on water pump bearing and power valve bearing. I'm assuming all you have to do is push the power valve slide in (towards cylinder) and tighten the bolt. I'm just not seeing any "bad" changes that I could have mmade.

Offline 81cr450

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Re: 1990 kx500 power valve issue
« Reply #5 on: May 04, 2015, 06:49:27 AM »
By load I mean place the governor in the clutch cover before you place it on the engine, "not" set the governor in the motor then put the cover on

The arm the 10mm nut retains is not indexed or keyed. Meaning you can put it in any position on the end of the shaft, when you tighten the nut it preloads the governor in the open position basically locking the powervalve closed.

Undo the nut , let shaft shaft return to its home position. Then hold the arm with pliers when you tighten the nut. Drop the pipe to verify the valves are closed , then use pliers to move the arm & see that they open fully & return fully to closed

X2 on water pump seal
« Last Edit: May 04, 2015, 06:53:05 AM by 81cr450 »
if I only had a pair, I could actually ride this thing

& to the people I like  FYYFF

Offline kawirider1469

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Re: 1990 kx500 power valve issue
« Reply #6 on: May 04, 2015, 10:08:24 AM »
Ok, got the clutch cover back off. I assume I just set the governor down into the clutch cover, then reinstall the cover?? Also, once all is hooked back up, should the power valve close on its on (like a stretched spring) or can I pull it out and it stays out? I can push the rod into the cylinder and pull it out and it stays where I let go of it at.

Offline dave916

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Re: 1990 kx500 power valve issue
« Reply #7 on: May 04, 2015, 10:43:34 AM »
governor in clutch cover will always be in closed position  [nothing to do here expect put it in the  grove }
push the kipps rod on the cylinder IN fully {closed position}
line up the  ,GOVERNOR  lever and tighten the 10mm nut

I would do this by removing the kipps rod collar {small circlip } and tighten the 10mm nut with the clutch cover off  , as any loading of the governor can have the needle bearings in goveror fall apart

dont forget to do ur water pump seal and bearing with clutch cover off 2x 608 c3 bearings and seal

 



Offline kawirider1469

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Re: 1990 kx500 power valve issue
« Reply #8 on: May 05, 2015, 12:17:38 AM »
After further inspection the governor was NOT hook onto groove!. thanks for all the replies and help! Now on to crank rebuild and new top end sleeve. You guys can throw out any advice on these subjects as well.. I'm not looking to build a race bike, just freshen the engine back to specs