Hi, I'm new to the club but badly in need of some help/advice please. My dtr 125 was running o.k. until the head gasket blew. I've fixed that but now the power valve doesn't seem to come in. I opened up the electrical/gear side of the cable-control unit and that seems to be working o.k. There is a motor fed by 2 lives giving out 11.7v each, but the smaller unit alongside the motor only seems to be getting 4.5v to each of the connectors. The valve itself seems free enough and when the ignition is switched on it turns, but doesn't return when the key is turned off without starting the engine. Could this unit be faulty or is it likely to be thd c.d.i.? I knicked a live when putting the head back on and blew the fuse from the battery, which was replaced and the bike started, but my son's nrg 50 pulls better and it's embarrassing!!! Iwould be really grateful for any suggestions. Thanks a lot. Jay.

Hi, if you dont have the manual here it is http://www.dtr125.net/workshop-manualf.htm Your ypvs sounds ok to me , when you turn on the ignition it will centre itself for adjustment , the semi circle on the powervalve pulley under the cover should line up with the hole on the backplate , this is shown in the manual . I have also sent you a pm .

Bob C

you could disconnect the electrics and pin open the power valve just as a tempory measure to make sure its nothing mechanical and only electircal

Hi, if you dont have the manual here it is http://www.dtr125.net/workshop-manualf.htm Your ypvs sounds ok to me , when you turn on the ignition it will centre itself for adjustment , the semi circle on the powervalve pulley under the cover should line up with the hole on the backplate , this is shown in the manual . I have also sent you a pm .

Bob C

you could disconnect the electrics and pin open the power valve just as a tempory measure to make sure its nothing mechanical and only electircal

Hi, tried that previously and bike runs o.k. as long as I keep the revs above 6500. I've put it back cos my son can overtake me on his NRG50, and now have further problem with the electrics, cheers, Jay.

Hi, tried that previously and bike runs o.k. as long as I keep the revs above 6500. I've put it back cos my son can overtake me on his NRG50, and now have further problem with the electrics, cheers, Jay.

Hi to everyone who tried to sort out my powervalve problem, this is the only way I know to get back to you all. It would seem that the answer was in the information that I gave in that a live-feed wire was knicked when tightening down the cylinder-head after replacing the head-gasket. This caused either a short or bad feedback to the cdi unit which wasn't apparrent at first,but subsequently revealed itself by the smell of cooking electrics. One 2nd hand cdi later and I'm mobile. All my own fault it seems!!! Shows you can't be too careful even at my age. Jay.

Hi to everyone who tried to sort out my powervalve problem, this is the only way I know to get back to you all. It would seem that the answer was in the information that I gave in that a live-feed wire was knicked when tightening down the cylinder-head after replacing the head-gasket. This caused either a short or bad feedback to the cdi unit which wasn't apparrent at first,but subsequently revealed itself by the smell of cooking electrics. One 2nd hand cdi later and I'm mobile. All my own fault it seems!!! Shows you can't be too careful even at my age. Jay.

Glad you sorted it, thanks for the feedback...