DT 125R MAN Posted October 23, 2009 Share Posted October 23, 2009 afternoon all, right ive finally got my power valve working a bit better when i turn the key the powervalve sets up and is inline with the dot/hole on the head ok and when the bike it running it move with the revs ok but when the revs pick up a bit and the power valve goes about a centimeter clockwise a rattling/knocking noise appears :\ is this normal? im guessing the powervalve cant hit the piston because i wondered if that was the noise? also i cant seam to get the bike to run right it will start fine on the choke and idle at about 2k and when warmed up ill take her off the choke and the revs pick up to about 2.5k for a few seconds and then the revs will start to slow down untill it totaly dies and if i go back onto choke will bring revs up to 2k again but after a while it will cut out! but if i keep the throttle on a little it will stay running fine:/ any one got any ideas? cheers Link to comment Share on other sites More sharing options...
Moderator Cynic Posted October 23, 2009 Moderator Share Posted October 23, 2009 afternoon all, right ive finally got my power valve working a bit better when i turn the key the powervalve sets up and is inline with the dot/hole on the head ok and when the bike it running it move with the revs ok but when the revs pick up a bit and the power valve goes about a centimeter clockwise a rattling/knocking noise appears :\ is this normal? im guessing the powervalve cant hit the piston because i wondered if that was the noise? also i cant seam to get the bike to run right it will start fine on the choke and idle at about 2k and when warmed up ill take her off the choke and the revs pick up to about 2.5k for a few seconds and then the revs will start to slow down untill it totaly dies and if i go back onto choke will bring revs up to 2k again but after a while it will cut out! but if i keep the throttle on a little it will stay running fine:/ any one got any ideas? cheers Your piston cannot hit the powervalve, thats the easy bit done. The rattling/knocking sounds like dettonation, added to what sounds like some carb problems. Favorite would be the main jet blocked as the choke helps things along. Looks like she's asking for a bit of TLC. Link to comment Share on other sites More sharing options...
DT 125R MAN Posted October 23, 2009 Author Share Posted October 23, 2009 did not think it could hit was just checking tho so thanks for clearing that up is there any way to stop dettonation? ive only just had the engine back from a rebuild its not even done a mile yet :/ cheers Link to comment Share on other sites More sharing options...
Moderator Cynic Posted October 23, 2009 Moderator Share Posted October 23, 2009 did not think it could hit was just checking tho so thanks for clearing that up is there any way to stop dettonation? ive only just had the engine back from a rebuild its not even done a mile yet :/ cheers Oh, how thourough was the rebuild? and was it done by someone who knew what they were doing/ were recomended to you by someone? If it was a complete rebuild then the engine builder should have set the ig timing before they put the flywheel back on they should also have re-bushed/decoked the powervalve if it was required. There should be no worries about the motor IF its been rebuilt properly. As far as the carb goes, take it off and give it a thourough clean internally checking all the airways and jets are clear. Set the float height and then re fit it. Use good fuel fresh from the pump (or no more than a couple of weeks old) and start it again. If you still get all the horrible noises i'd consider taking it back to the person that 'rebuilt it'. Link to comment Share on other sites More sharing options...
DT 125R MAN Posted October 23, 2009 Author Share Posted October 23, 2009 it was a guy who used to work for a motorbike garage for many years! i had a new piston rings rebore new big end and small end bearings :/ ok cheers ill get on with the carb now Link to comment Share on other sites More sharing options...
Moderator Cynic Posted October 23, 2009 Moderator Share Posted October 23, 2009 it was a guy who used to work for a motorbike garage for many years! i had a new piston rings rebore new big end and small end bearings :/ ok cheers ill get on with the carb now Did he sell them or fix em Sorry thats not fair. If you have had piston,rings,bore and CRANK bearings done then there shouldn't be anything to worry about inside. It should all have been delt with in the build. Check out that carb. Link to comment Share on other sites More sharing options...
DT 125R MAN Posted October 23, 2009 Author Share Posted October 23, 2009 thanks for all your help one thing i did try was unpluging the powervalve and then reving it up to where i had heard the noise before and with it unpluged it does not do it :/ cheers Link to comment Share on other sites More sharing options...
Ryan09 Posted October 23, 2009 Share Posted October 23, 2009 My bike used to rattled... once it seized. I done the top end rebuild which took most of the piston slap away but there may have been a little play in the crank (irrelavant here). Was it done or did he say it was done, (2 difrent things). Link to comment Share on other sites More sharing options...
DT 125R MAN Posted October 28, 2009 Author Share Posted October 28, 2009 My bike used to rattled... once it seized. I done the top end rebuild which took most of the piston slap away but there may have been a little play in the crank (irrelavant here). Was it done or did he say it was done, (2 difrent things). yeah it has been done because for a start the old piston had smashed Link to comment Share on other sites More sharing options...
DT 125R MAN Posted October 28, 2009 Author Share Posted October 28, 2009 right ive cleaned out the carb with some carb cleaner used a whole can to make sure its nice and clean! but still wont run with out choke other thing ive just noticed is the boost bottle is missing he has just pluged it up :/ could this be why i wont run right? cheers Link to comment Share on other sites More sharing options...
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