DT125R SM suddenly cut out,Now wont start.Powevalve has stopped cleaning cycle



  • Hi everyone

    Been lurking in this fourm for a while and thought id ask for your expertise

    I was recently riding slowly through my town when my dt suddenly died and ground to a halt, it has not seized. i tried to bump start to no avail, i got into my garage to find it has a spark and put my thumb over the plug hole to do a poor mans compresion test(im not sure what to look for here but i did feel a pulse of quite strong air).I recently had it serviced as i do with any new motorbike.

    Unfortunately it was done by cowboys. who while messing with the loom (it is old and corrodied they told me) accidently dissconnect the PV then Didnt do up the front head lamp nuts and as i was riding away with a bike that wouldnt bite the light was also slipping down. eventually they fixed all the problems and im not sure if what has happened now has anything to do with them

    anyway, when i turn the key theres no Zssst zsst from the PV and the stater motor just keeps turning. after a while of trying to start the exhaust will sound like a loud sneeze or a puff, im taking it to bits to see if somehow the power to the PV is comprimised. i just wanted to ask if you have any ideas, The plug is in great condition with a perfect biscuit brown electrode dome

    thanks guys, appreciate it



  • Is it getting fuel?

    The powervalve won't stop it starting.

    If it is sparking then



  • hey thanks for responding

    Im not sure how i would find that out. maybe clean the carb, a jet could be blocked ?



  • @MattD Work logically. Start at the tap and work your way to the plug. To be fair if you were turning it over then you should see the plug will be wet.

    If it was running and now not running and the powervalve is a bit sketchy then it sounds like an intermittent electrical fault. But you say there is spark. If there's spark, compression, fuel and air then it will ignite.



  • Its all so crowded in there im taking the seat of and the tank to get a better view of everything, sorry. my knowledge to this sort of stuff is very limited and im a noob at diagnosing anything or working logically with a bike. i feel i should get an ohmometer to test all the electrics are working properly. im thinking it could be some sort of ignition fault



  • @MattD thats alright gotta start somewhere. Can't stress enough the value of a Haynes manual. Best thing you can buy for one these.



  • so i just got the tank off and the loom is a right mess. i can post a pic if it helps
    i noticed when i turn the key the pully for the PV does tense up and move slightly but not the full movement. im thinking of buying a whole new loom and with a haynes manual re doing it, i still dont understand why the pv and igntion both dont work because like you said it starts without the powervalve



  • @MattD thatis fine it will do that.t


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