Hueligan Posted August 10, 2014 Share Posted August 10, 2014 Hi folks, I recently bought my son a 2006/7 DT125X. It had been advertised as being in original condition but, upon delivery, I noticed a bright blue wire leading from behind the headlight assembly to the chassis. I had previously read about a DIY bypass for the YPVS which entailed cutting a wire leading into the ignition block and earthing it onto the chassis and sure enough this is what has been done to it. I reinstated the wire as it should be as I think Mr Yamaha probably knows more about building bikes than I do but the YPVS did not work. Investigation showed that not only had the bypass been fitted but some bright spark had also cut the 5 wires leading from the YPVS servo assembly. I reconnected them and plugged them into the appropriate connector block. When I turn the main power on I can now feel a small click in the servo unit but it does not turn the pulley and perform a full cycle of the valve as I believe it should. It also does nothing when the bike is actually running. I have noticed a further 2 connector blocks which I assume should have something plugged into them? The bike is fitted with a CDi unit which is located under the petrol tank. Does this run the YPVS or should there be a separate YPVS controller (perhaps plugged into those 2 spare connectors)? I do have a PDF version of the service manual for the bike but it doesn't say a lot about the YPVS other than how to adjust it. The wiring diagram is a bit too complicated for me to understand without some guidance. Any advice would be gratefully received. Regards Hue Link to comment Share on other sites More sharing options...
blackhat250 Posted August 11, 2014 Share Posted August 11, 2014 Aye hue " the power valve may be needing cleaned , or is worn , that be why some ass cut wires , Link to comment Share on other sites More sharing options...
KevtheRev Posted August 11, 2014 Share Posted August 11, 2014 I'm not sure whether the P.V. is cable operated on your bike but if it is , check the cables as they seize if not lubed . Link to comment Share on other sites More sharing options...
whitley89 Posted January 11, 2015 Share Posted January 11, 2015 Hi there sorry to resurrect a dead thread but did you solve the issue at all? I'm having a similar issue and like you say the haynes manual has little info on the workings of the YVPS system which is immensely irritating, Cheers Link to comment Share on other sites More sharing options...
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