Power valve will not open?

[GNCC387]

I have a 1999 rm 250 and the power valve will not open when u rev it sitting on the stand and then it opened and stuck for a few then it shut. I have put the new govenor on the bike and it still isn't working> Any help at all would be appreciated. Thanks in advance

 

[Mike198]

it could be carbon build up on the valve, have you ever cleaned the power vavle?

 

[el presidente]

he takes very good care of his bike, he has been working w/ this problem for about a month and a 1/2 now. he has cleaned his valve about 4 times in that time period, and we can't figure out what is wrong.

 

[endosports]

Have you taken off the right side cover and inspected the mechanism that operates off the lower end?

My old roomate had the same problem but didn't know about it until he tried an 80 foot double and came up way short.

 

[GNCC387]

I have taken the cover off and i watched it work while it was running on the stand and i decided to replace the governor in the bottom end cuz a buddy of mine had the same problem and that fixed it. Mine is still not working properly. When i first noticed it not running right i took the reed block off and it had a broke reed (has a v-force reed block) so i replaced it and i figured the problem would be sovled and it wasn't so we figured it had to be the power valve. So i have been screwing with the power valve ever since. I need to have it working properky cuz the GNCCs start back up in a couple weeks. Thanks for the info so far but i have already tried that stuff.

 

[Stew312]

When you have the engine apart, do the valves slide in and out easily when you pull them with your hands?? If you got a new actuator, and your sure that is working properly, there has to be something stopping the valves themselves from moving in and out like a warped valve or valve housing. Did you make sure to cover them with 2-stroke oil when you put them back in??

 

[GNCC387]

I covered them in oil when i put them back in and they do work freely when u mess with them.

 

[Stew312]

Then the problem is with the actuator in your crank case. Take it apart and inspect the actuator very closely, that is the only place the problem could be.

 

[Stew312]

One more thing, on my 88 RM250, there is a rod that comes up to the head where the exhaust valves sit from the actuator (right side of engine). This rod pushes up a arm, that rolls a bar counter-clockwise (which goes through the tops of the valves and closes them), which connects by a spring. This spring HAS to be on properly or else the valves will not work well and will stick open (which is their origional position. The spring has 2 arms that come down and surround two small ends of levers, which allow them to move freely, but keeps them together unless there is alot of force in opposite directions. This spring is very often put on wrong, with the arms crossed, when the arms must be straight for proper operation. Do you have the book and follow it exactly when you put the valve train back together? I'm not sure how much the design has changed from 88 to 99, but its most likely the same general idea. I hope you can see what I'm trying to explain, its fairly difficult on paper without a drawing. Also, check the left side of the engine where the tensioner sits. Make sure everything is ok there. Good luck.

 

[GNCC387]

Thanks for the info but the powervalves seem to work smoothly they just will not work any other suggestions

 

[Stew312]

Could be your timing, pull your flywheel and check the woodruff key to make sure its not sheared. Bad timing will not let the bike rev high, which may also look like its the power valves not working.