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  #1  
Old 03-31-2004, 07:11 PM
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Question PowerValve Closure?

     

hey guys
i decided to check my bike over tonight for the whole bogging out thing.......checked my reeds, they're good, i took off my powervalve cover, wiped out some of the spooge that had puddled up, then i took off my pipe, and looked up through the exhaust port, and i noticed that my powervalves were open, then i slowly kicked the bike over, and they still were open, should they be open? thanks...

:
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Old 03-31-2004, 07:24 PM
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Default Re: PowerValve Closure?

No they should be closed at idle (or off) and open at higher Rs. Theres your problem. Start taking it apart and cleaning everything. You may want to use some very fine wet/ dry sandpaper with water on the slides to make them like new again.
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Old 03-31-2004, 07:48 PM
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Default Re: PowerValve Closure?

but as I look closer up the exhaust port, it looks like they can't even close any more, there's just no room, and i took off both powervalve covers and cleaned it up as much as i could w/o going TOO much into it.........and i could operate them from the "side" powervalve cover linkage (you know what i Mean?) and everything operated smoothly, opened and closed, but the actual valves are only closed half way.......and they don't look like they can close any more......i'll try to get some pics up.....
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Old 03-31-2004, 07:53 PM
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Default Re: PowerValve Closure?

Oh I just went by what you said. Do you have the manual? If your able to slide them in and out then thats probably not your problem after all. You should be able to tell if they hit the stops when shut.
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Old 03-31-2004, 07:54 PM
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Default Re: PowerValve Closure?

Cleaning the spooge out of the linkage area is not going to help the powervalve open and close..thats not what makes them stick...the actual valves in the exhaust port are what sticks..which results from carbon build-up from the combustion process. I am not sure how that powervalve is set up...don't know if there is a way to check to see if it is operating right...my CR has the linkage cover on the right side of the cylinder and an inspection cover on the left side that you can take off..start the engine and it has a slot that lines up with an "L"...you rev the motor and if the slot(which is acutually just carved in the end of the left sub valve)turns to the "H" then the valves are opening all the way.
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Old 03-31-2004, 07:56 PM
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Default Re: PowerValve Closure?

BTW...while you have the pipe off..take a look at the piston and tell us what it looks like. Or take a picture. You can tell quite a bit about ring condition by looking at the piston through the exhaust port. You will be able to see blow-by marks.
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Old 03-31-2004, 07:57 PM
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Default Re: PowerValve Closure?

okay, i get what you guys are saying, and i think that they are operating(opening, closing) fine, and Matt, my bike does have some sort of inspection cover on the left side of the cylinder, tommorow, when i get it back together, i'll see if it moves at all.......thanks guys.......
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Old 03-31-2004, 07:59 PM
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Default Re: PowerValve Closure?

Quote:
Originally posted by MATTXR250R
BTW...while you have the pipe off..take a look at the piston and tell us what it looks like. Or take a picture. You can tell quite a bit about ring condition by looking at the piston through the exhaust port. You will be able to see blow-by marks.

I'll try to get some pics up tommorow before i have everything back together, but from what i see, the piston/ring looks fine......but i'm no expert......
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Old 03-31-2004, 07:59 PM
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Default Re: PowerValve Closure?

It would be a good idea to take the PV apart and clean it properly anyway since your working on it. Sometimes carbon builds up or it gums up to where it wont close 100%.
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Old 03-31-2004, 08:04 PM
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Default Re: PowerValve Closure?

I think Roostman might be onto something here...The powervalves when closed...sit up in a slight recess to clear the exhaust port for maximum flow...while the valves are open I guess it would be possible overtime for carbon deposits to build up in this recess and cause the valve not to close all the way.
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Old 03-31-2004, 08:09 PM
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Default Re: PowerValve Closure?

ooo,
now it's starting to sound like Chinese....haha jk
just to clear one thing up.......Closed=when the actual valves are blocking exhaust port?
Open=when the actual valves are "tucked away" and giving the exhaust port the full diameter?

i'll try to get some pics up as soon as possible.
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Old 03-31-2004, 08:16 PM
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Default Re: PowerValve Closure?

Correct..when the valves are closed the will block some(not all) of the exhaust port...this gives the motor more back pressure which results in a little more low-end power...Then as the RPMs pick up the valves open and move up to clear the exhaust port...my CR has a governor in the cases....works basically just like a centrifucal clutch...as the RPMs increase the governor spins faster and slings weights out which turns the shafts and then turns the linkage clockwise which opens the exhaust valves.
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Old 03-31-2004, 08:16 PM
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Default Re: PowerValve Closure?

ok, i just snapped a couple pics, i know they're horrible, but i'll try to explain what your looking at, the "white" part your seeing would be the piston, does it look like the valves are closed enough?
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Old 03-31-2004, 08:17 PM
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Default Re: PowerValve Closure?

sorry, but i suck at downsizing pics, so it cut it in half nearly, but you should get the point......
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Old 03-31-2004, 08:18 PM
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Default Re: PowerValve Closure?

I can see the piston but can't make out anything else.....
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Old 03-31-2004, 08:22 PM
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Default Re: PowerValve Closure?

sorry, but i'll try to explain this........you can see the circle, look in the circle, the whiter part inside that circle would be the piston, and the black above that is the valves, they are covering about 1/4 of the port...........hope you can make this out.......if not, i'll get better pics up tommorow..
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Old 03-31-2004, 08:26 PM
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Default Re: PowerValve Closure?

Well I will say this...My CR has 3 exhaust valves....2 sub valves and 1 big flapper valve. The flapper valve is in the middle of the exhaust port. I am not positive because I haven't looked in a while but I think when closed it blocks somewhere between 1/4 and 1/2 of the port and when open blocks none.
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Old 03-31-2004, 08:27 PM
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Default Re: PowerValve Closure?

o, there's only 2 valves in my bike........and they both work in sychronization (sp?)
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Old 03-31-2004, 08:29 PM
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Default Re: PowerValve Closure?

Spit..I am gonna go to www.partsfish.com and pull up a parts diagram of your powervalve. If i see a picture I will probably be able to tell how yours works and might can help your out more...
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Old 03-31-2004, 08:32 PM
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Default Re: PowerValve Closure?

Well,darn...nevermind that...Partsfish doesn't list an RM125...they list the RM60,80,100,85,etc but no 125....:
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