What if ACTUATOR isn't connected (RE:RM250 exhaust valve)??

[rodH]

In the thread listed below, I talk about how I do NOT think my exhaust valve is working properly. I checked everything that I thought it would be (I was convinced after reading that if the spring was crisscrossed, that that was going to be my problem, but after going home and taking the whole dumb thing apart, that was NOT my problem!!!!!, BUT, BUT, BUT....I look next to the spring at the outer lever and I notice that the Rod isn't connected AT ALL to the outer lever, so I connect this ROD, but it feels like it isn't connected to ANYTHING inside the crankcase???? But I put it back together and test it out.......SAME PROBLEM :bang:

As I completely take the crank case apart to see what I find is connected to the other end of this ROD, and it is connected, BUT NOT CONNECTED PROPERLY, at the end where it is supposed to go in the hole of the Actuator, it isn't actually in the hole, it just slides back and forth without actually moving the ACTUATOR!!!! (or the actuator when it moves, would have NO EFFECT on the rod, which means it would move the outer lever/exhaust valve)

My conclusion is that this HAS to be my problem, unless this doesn't really "actuate" anything, but with a name like the "ACtuator" that is connected to the exhaust valve, I would imagine this has to be it. To learn more about it, I read my manual and this is what it says it does......

"This variable port action of the valve assembly is controlled by a governer (this governer assembly sits right next to the actuator, turning it) that is driven by the crank shaft. The governer is linked to the valve assembly by a control rod, and the valves open and close automatically, depending on engine speed"

In other words, since this was NOT connected at all, I guess that the engine speed was NOT changing the valve position at all, thus making it ineffective???? Does this sound like it may have been my problem??

I am just curious on some thoughts because in the process of taking the rod out, I broke the rod bushing and was not able to put it back together and test it yet (hopefully tomarrow, if anyone has one in stock??)

THOUGHTS??????


http://dirtrider.net/forums3/showthread.php?t=120399

 

[2-Strokes 4-ever]

On my sons 98 Rm125, we've had the power valves break twice... not really sure why, maybe just wear and tear. The shaft that IS the valve itself broke and the valve walked out into the piston, causing piston damage. A new valve ($80 bucks a pop) plus piston replacement and we were rolling again. One valve broke, then the other about a year later. Don't know if 97 250 is same design, but keep on eye on it.

 

[rodH]

this HAS to be the reason my recent piston was all scuffed up by the power valve. Hope my new one isn't too bad (2 rides), at least I found it now VS later.

 

[RM_guy]

You may have 2 different problems. 1) the rod wasn't hooked up and 2) the valve is broken and is protruding into the cylinder. Does the valve stick into the cylinder?

 

[rodH]

You may have 2 different problems. 1) the rod wasn't hooked up and 2) the valve is broken and is protruding into the cylinder. Does the valve stick into the cylinder?

I always thought that it was sticking since it really wasn't moving much, but after moving it by hand, it is free to move, the problem seems to be that the rod was never pushing it up to move, that has to be the problem.

 

[rodH]

craaaaaaaap!!! I got the new clips and put it back together. It still runs like CRAP, absolutley NO POWER :(

 

[steve125]

With the PV cover off and the pipe back on......have you tried running the bike and see of the PV linkage moves? If you know all is working well in the cylinder/by hand. Then just confirm if the PV governor is working by taking a look while running.

Start the bike up with the cover off and rev it a few times, if nothing moves then find out why.

 

[RM_guy]

Chaeck the preload on the valeve spring. Not sure what it is for a '97 RM250. Something I posted in another thread:

As far as the PV spring tension, the amount of preload is not the same every year. I'd call your friendly local dealer and ask them what the manual says. In any case it is from the free state of the spring and is in a clockwise direction. It can be anywhere from 1/4 to 1 turns. I think the '99 was 3/4 turn if you can't find out. The tension controls at what rpm the valves open so if you find that the power band kicks in to late (it almost feels like a lean condition and it bogs) you have it too tight. Back it off 1/8 of a turn at a time until it acts the way you expect it to act. It would help to ride another bike to see how it should act.

 

[rodH]

With the PV cover off and the pipe back on......have you tried running the bike and see of the PV linkage moves? If you know all is working well in the cylinder/by hand. Then just confirm if the PV governor is working by taking a look while running.

Start the bike up with the cover off and rev it a few times, if nothing moves then find out why.

Yes, it is moving now,

here is a link to my thread in another area that chronicals what has taken place, this is soooo frustrating :bang:

http://www.dirtrider.net/forums3/showthread.php?p=952207#post952207

 

[rodH]

Chaeck the preload on the valeve spring. Not sure what it is for a '97 RM250. Something I posted in another thread:

As far as the PV spring tension, the amount of preload is not the same every year. I'd call your friendly local dealer and ask them what the manual says. In any case it is from the free state of the spring and is in a clockwise direction. It can be anywhere from 1/4 to 1 turns. I think the '99 was 3/4 turn if you can't find out. The tension controls at what rpm the valves open so if you find that the power band kicks in to late (it almost feels like a lean condition and it bogs) you have it too tight. Back it off 1/8 of a turn at a time until it acts the way you expect it to act. It would help to ride another bike to see how it should act.

The spec tension is 1/2 turn on both springs. No change in my problem :bang:

 

[ryan123]

Thanks this info has been handy. I just fixed my 98 rmx250 with the same sounding problem. Mine was either float height adjustment, moving the main pin in the carb, cleaning out the carb(not that there was any blockages that I know of), cleaning the back of the coil mounts and frame real nice, I did fully stip down the top end looking for stuff gone wrong but changed/fixed nothing. I can't say exactly what fixed it cause I did it all at once. I have a suspicion it was the carb float level it was set to 25mm rather than the correct 16mm for the 98(so I'm told). And I thought it sounded rich, using heaps of fuel, black stuff everywhere. F*cks me.
but it runs sweet. Fangs once again.

ps my actuator didn't feel connected at the bottom either. I just left it