Force Posted October 2, 2012 Share Posted October 2, 2012 Help needed quickly! I have a DT125RE (2006 model) and I also have my bike test in 3 days for my full (UK) licence. I was out practicing for my test this morning when all of a sudden the bike was losing power and was being very unresponsive when I was pulling on the throttle. The bike was making loads of noise as well. It turns out that the servo motor for the power valve (YPVS) had died on me! I phoned up my local bike garage (the only one near me) and they said that they couldn’t see to my bike until next week, after the test. Is it possible to ride the bike with the valve pinned? I’ve noticed that when you take the cover off the power valve there is pin hole on the black rotating part that lines up with the a hole in the housing. Would it be ok to pin the valve in this position to use the bike? I've read stuff about pinning the valve in position on DT125's. I don’t want to do it if it’s going to damage the bike but I won’t mind doing it just to get through the test. I don’t want to cancel the test because it’s a massive waiting list to rebook it! Thanks. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted October 2, 2012 Moderator Share Posted October 2, 2012 The bike should be fine with the valve static. You may have to fiddle a little to get the right balance of power and rpm. The bike will be different and you will be down on power a little. Bit of saddle time will sort that. As to securing it if the motor is dead anyway just turn the motor pully by hand, after dissconnecting it. (Just in case it starts erraticly.) To a spot that works. The 2 holes are for setting the cables up. Where that leaves the valve i dont know. There are people on here that do though so your test is safe. So now the panic is over say hi properly in the new members area. Link to comment Share on other sites More sharing options...
Force Posted October 2, 2012 Author Share Posted October 2, 2012 Thanks for the quick response. As it turns out, the servo motor hadn’t died completely. It still tries to move although I’m not sure if it’s working properly. When I take off the cables and turn the electrics on, the motor rotates anticlockwise, stops at the 90° position (270° anticlockwise from top position) and shudders briefly in this position and just stops. Is this normal? With the cables on, the motor still only tries to turn anticlockwise making the right hand cable go tight and the left one slack, sometimes causing the left hand cable to pop off out of motor pulley. When the right cable goes tight the motor stops, then tries to turn anticlockwise again then just stops in this position. I’ve had a friend look at it who used to be a mechanic but he’s not sure as to why it can’t be set up properly. Does this mean I need a new servo motor? Cynic, you seem to know your stuff pretty well Will go say hi in the new members area later Link to comment Share on other sites More sharing options...
Moderator Cynic Posted October 2, 2012 Moderator Share Posted October 2, 2012 Without wanting to state the obvious you have checked the cables are free. Different models have different PV opperation. They all run through a cleaning procedure that has the motor rotate fully through its opperation range. The pv changes the exhaust resonance so the engine stays "on the pipe" better. It doesent meen its always wide open. It just keeps the optimum port shape for, in the case of a race bike ultimate power. Or for the DT, torque and control. There is a more than just a motor in the motor, er you know what i mean. Its called a stepper motor as it tells the controller its position. If this signal is confused it may well be right out of control. Diagnosis? Could be the motor, could be the cdi or pv controller (it is separate units on some models) sticky cables, even the powervalve its self sticking. Any are possible. Link to comment Share on other sites More sharing options...
Force Posted October 2, 2012 Author Share Posted October 2, 2012 I checked the cables were on there properly. I knew that they run through the cleaning procedure when you turn the switch on because you can hear it whirr one way then the other when set up correctly. Checked the cables and they aren't sticking and neither is the power valve, they all run freely so I reckon it must be a signal problem. What do you reckon the best temporary fix would be then? Shall I disconnect the power to the servomotor and just move the PV to different positions until I find one that works well? I appreciate your help, thanks. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted October 2, 2012 Moderator Share Posted October 2, 2012 it might be a stuck power valve, take off the pulley and work it back and forth without damaging the flats. You can make a proper job of it later after your test is over Link to comment Share on other sites More sharing options...
Moderator Cynic Posted October 2, 2012 Moderator Share Posted October 2, 2012 I checked the cables were on there properly. I knew that they run through the cleaning procedure when you turn the switch on because you can hear it whirr one way then the other when set up correctly. Checked the cables and they aren't sticking and neither is the power valve, they all run freely so I reckon it must be a signal problem. What do you reckon the best temporary fix would be then? Shall I disconnect the power to the servomotor and just move the PV to different positions until I find one that works well? I appreciate your help, thanks. That would be my choice. Link to comment Share on other sites More sharing options...
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