bigjim1994 Posted November 29, 2010 Share Posted November 29, 2010 hi i have a yamaha dt50 mx 1987 and have no spark. i have just rebuilt it and swapped the engine from another dt50 from the same year. is there anything that i could have blown or not connected correctly or forgot to wire. hope someone can help me thanks . jamesx Link to comment Share on other sites More sharing options...
FZR AL Posted November 29, 2010 Share Posted November 29, 2010 hi i have a yamaha dt50 mx 1987 and have no spark. i have just rebuilt it and swapped the engine from another dt50 from the same year. is there anything that i could have blown or not connected correctly or forgot to wire. hope someone can help me thanks . jamesx Hi BigJim, have you put a multi meter and checked the readings , good battery, power to coil , coil to plug , does any off the elecrics work at all , could be just a bad earth ,check the loom for breakages and fusty connectors if you have rebuilt it and had the frame powder coated you will need to re tap the thread for it to earth out we could do with a bit more info cheers al Link to comment Share on other sites More sharing options...
Moderator Airhead Posted November 29, 2010 Moderator Share Posted November 29, 2010 is the battery good neutral light on ignition switch on kill switch off Not familiar, would need a wiring diagram, some bikes are magneto ignition and are not too fussed about the battery As a quick test...is there a Black/white wire to the CDI?...if so can you unplug it without unplugging others...if so try that...spark now? Link to comment Share on other sites More sharing options...
Speedshop Posted November 30, 2010 Share Posted November 30, 2010 The battery has nothing to do with the ignition on these bikes. It has self generating CDi. You need to find a manual and go through the tests for the source windings, pick up, bike wiring and coil checks. If every thing else is OK its the CDi unit that's gone. I'm assuming you've changed the spark plug and HT cap already .................... Link to comment Share on other sites More sharing options...
bigjim1994 Posted December 1, 2010 Author Share Posted December 1, 2010 hi. yes i have changed the ht cap and ht coil(and lead) so if there is still no sprak what good is a new spark plug because a new one wont even spark if the ht lead isnt sparking. if i am wrong please tell me. someone i spoke to mentioned it could be the contact breaker points have closed if so how do i open them and do i need to take the flywheel off. if i do that will then require a fly wheel pulley i presume? are there different ones for different bikes or are they all the same? thanks james x Link to comment Share on other sites More sharing options...
Moderator Airhead Posted December 1, 2010 Moderator Share Posted December 1, 2010 a 1987 bike will not have contact breakers, I suggest you buy a manual then you would have a better idea, manuals can be bought quite cheaply on ebay as a rule. So how did disconnecting the black/white wire go? Link to comment Share on other sites More sharing options...
Speedshop Posted December 2, 2010 Share Posted December 2, 2010 I've looked they were indeed points, you can check the gap with the flywheel on. Very odd as not many mopeds had points that late. Second the advise above, get a manual then you'll be sure. Your local library will be able to get a Haynes book if they don't have one in - for free. Link to comment Share on other sites More sharing options...
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