Right powervalve opens 1 mm sooner?

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two20R
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Right powervalve opens 1 mm sooner?

Post by two20R »

On a 2002 KDX220R, when operating the power valves manually, both valves begin to rotate at the same time but the right one opens its port first. It seems the right port is always open about 1mm more than the left one. When they are rotated into the closed position, both the right and left ports are closed off, but the left valve is rotated about 1mm further than necessary to close the port. All the teeth are in synch per the instructions in the service manual and the system is clean and appears to be in good condition. Does this sound correct, or are both valves supposed to open their ports the exact same amount at the same time. Thanks!
two20R
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Right powervalve opens 1 mm sooner?

Post by two20R »

Here's a pic of the right side valve and rod, which seem to be in good shape....correct?

[URL=http://s988.photobucket.com/user/f ... .jpg[/img][/url]
KarlP
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Re: Right powervalve opens 1 mm sooner?

Post by KarlP »

I've never noticed that. Can you shift one valve set one tooth so that they open and close the same?
What you have pictured is the right side vale (RH when sitting on the bike). They look good.
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two20R
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Right powervalve opens 1 mm sooner?

Post by two20R »

Thanks for the suggestion KarlP... (War Eagle! by the way).
I tried shifting one of them over by one tooth, but that makes them further out of synch in the opposite way, and the alignment marks would not be in the proper position per the manual.
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bufftester
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Re: Right powervalve opens 1 mm sooner?

Post by bufftester »

They are not exactly aligned (at least not on my 2001 220 motor my left opens just slightly earlier, but at main valve close they are fully closed and main valve open they are fully open which is the more important fact). Since they spend very little time in the transition phase it's not much of a concern as making sure they open and close together.
two20R
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Right powervalve opens 1 mm sooner?

Post by two20R »

It's good to hear that the sub valves don't necessarily open exactly in sync with each other. Nonetheless, I was able to adjust the travel of the left sub valve independently of the right by loosening the Main Shaft Nut and rotating the left Main Shaft Pinion / left Exhaust Valve Rod / left Sub Valve independent of Main Shaft. It was hard to keep it all in place while tightening the Main Shaft Nut because tightening the Main Shaft Nut tended to rotate the left Main Shaft Pinion back to the the full clockwise position. But with my son lending a third hand and holding the left Main Shaft Pinion in place, it was done.

It was also good to learn that in operation, the valves snap open and shut, thus rendering minor differences between them in any partially open condition, not very significant. Even before I made the final fine adjustment on mine, there was very little difference between them in the fully open and fully closed positions, which is where they spend almost all their time.

Thanks for the help!
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