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2-stroke valve broken?

Joined
Jun 2, 2007
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#1
I was wondering if the PV(?) valve in my CR250 is normally always opening and closing at any RPM range? I have my head off and when I push my bike in gear the valve does not move at all. I am 100% positive the two little links are mated properly between the cylinder and the bottom end. What could it be, if this is not normle?
Also, when I get to higher RPM"S my bike loses power like crazy.
Any help is greatly appreciated. :ohmy:
 
Joined
Jul 17, 2006
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#2
well if the power valve has gumk in it it wont activate properly, so give it a thorough cleaning and see how you go.
 

IndyMX

Crash Test Dummy
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#3
Power valves don't operate like that.

They are normally closed at low rpm's and open at high rpm's.

They don't continually open and close.

If you look at the regulator, you'll see that it has a sort of centrifical clutch that opens it up.
 
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#4
That makes perfect sense! Thanks alot for the help, I appreciate it. Just to be on the safe side I think I shall clean it since my bikes apart anyways. Thanks again!
 
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May 28, 2006
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#5
same thing happend on my 93 cr250, i found out the power valve govner was worn out and no longer activating the power valves.
 
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Nov 13, 2005
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#6
check PV operation by removing cap on left side of cylinder with 17mm wrench. at low rpm, notch in shaft will align with "L" mark. At hi rpm, shaft will align with "H" mark.

Another common reason for PV not working: PV linkage not installed correctly when clyinder has been replaced.
 
Joined
Apr 18, 2006
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#7
like 2bitsamile said, you can usually do a visual check on the linkage to the PV and see if it is operating properly. The PV is operated off of Engine RPM so you can be revvving it up in neutral and watch the linkage move. No harm will come to the engine by having the cover off while you run the test. Don't ride the bike with cover off though!

Rod