Honda RC Power Valve Failure

[Phil72]

Hello,
My 2003 CR 250's RC power valve is not working. The problem is in either the servo motor or the engine control module. The actual power valve shaft rotates freely (no carbon build-up). I have checked and adjusted the cables. The wire harness is in good shape, all connectors were checked. Any ideas how to isolate the problem without going to the honda dealer? Has anyone else had this problem. Thanks in advance

Phil

 

[NO HAND]

yep, take a 12 volt batery and try to connect it for a very short time to the servo motor only. If the servo motor starts spinning, it means it is fine. Also, you could connect a voltmeter to the connector from the cdi that leads to the servo. If you see it indicates some voltage when you rev the bike, the cdi is fine. remember the current burst is short because it only has to flip open the pv. So, it means it is normal you won't have 12v long enough to have a clear reading on the volt meter, but long enough to see the voltmeter move and try to display a different reading.

 

[Phil72]

No Hand,
Sounds good, there are 5 wires going to the servo motor, which two would I check the voltage across. If I check the servo motor with the 12V car battery, won't this have too much current? Thanks in advance.

Phil

 

[NO HAND]

No worries, it is made to run on 12 volt. The wire that is (white and black) is positive and the one that is (white and green) is negative. This will make the motor turn clockwise. Invert the wires after to try it counter clockwise and see if it works fine both ways. I found some info on this on page 69 on the owner's manual. Is it possible that only the connector has some corrosion from washing the bike. Perhaps some wires may have been damaged. I noticed all the wires are very small and fragile. Let me know what you find and what part needed to be changed. This got me worried of having the same thing happening to me. I too got an 03CR250. Good Luck!!

 

[Phil72]

No Hand,
Checked the connectors, all clean, checked the wire harness, no fraying. The servo motor is not always easy to rotate cw/ccw. Sometimes it hangs up and requires a larger force (3x). I called my local Honda dealer to ask if they could check either the CDI or the servo motor. Reply: they don't know how to do it, I can come in and look at the sevice manual all I want. Poor answer, but I might take him up on the sevice manual review.

One other point, just because the motor turns cw/ccw with a 12V source, does not exzonerate (sp) the servo motor. The control loop (other 3 wires) could have failed. I will let you know what happens next.

Phil

 

[Faded]

I'm interested in the out come as well...

 

[Phil72]

The problem was the servo motor. I decided to open up the assembly and inspect. The motor was corroded very badly. I cleaned it up as best as I could and its performance was only marginal ( and took 15V to mave the motor turn and it ran ruf). I have the new part on backorder - nobody has it in stock. I normaly keep by bike very clean. I did not see any failure of the o-ring that seals out dirt - cant quite explain it.

Phil