motorlou Posted September 27, 2009 Share Posted September 27, 2009 Hey everybody, i am new to this board and joined because i need alittle help from the dirt bike gurus. i am a chopper enthusiast and am trying to help a neighborhood kid who came to me looking for help. he saw that i work on bikes in my garage and stopped to ask if i could fix a dirtbike he found. i believe the bike is a late 60's to early 70's yamaha dt250? he found the bike abandoned in a field close to his home. it had been sitting there for years but the frame and engine where still there, everything else people took off. there were still some wires connected from the engine to the coil. my question is if anybody could help me figure out how to connect the wiring so i can try to start the bike. i have found some wiring diagrams online but they are stock. i would just like the simplest way to connect it so the bike will turn on, i am not worried about lights or anything like that. i will try to attach a drawing of how the bikes wires are connected when we found it. any help would be greatly appreciated as i want to get the kid enthusiastic about bikes, it's a great hobby!! thanks fellas, Lou Link to comment Share on other sites More sharing options...
Moderator Airhead Posted September 27, 2009 Moderator Share Posted September 27, 2009 Hi Lou and welcome to the forum. It might be an idea to identify the bike using the engine / frame numbers then we can have a look at the original diagram if we can find one. ...Paul Link to comment Share on other sites More sharing options...
motorlou Posted September 27, 2009 Author Share Posted September 27, 2009 hi and thankyou for replying, i think i will try that. i will go over to the kids house and take some pics later this afternoon. Link to comment Share on other sites More sharing options...
motorlou Posted October 5, 2009 Author Share Posted October 5, 2009 well got those #'s off the neck, i still believe it is a dt250. the #'s are DT1F-25264. the sticker says 1970. someone told me to see if there was any current being produced from the stator so i started playing with the bike. i set my voltmeter to AC volts and connected it to the yellow and black wire then kicked it over. the reading was coming in at max of 9 or less volts depending on how hard i kicked. how much should the reading be? i also connected a know good coil to the bike but still no spark. do these bikes require a battery to start them? Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 5, 2009 Moderator Share Posted October 5, 2009 well got those #'s off the neck, i still believe it is a dt250. the #'s are DT1F-25264. the sticker says 1970. someone told me to see if there was any current being produced from the stator so i started playing with the bike. i set my voltmeter to AC volts and connected it to the yellow and black wire then kicked it over. the reading was coming in at max of 9 or less volts depending on how hard i kicked. how much should the reading be? i also connected a know good coil to the bike but still no spark. do these bikes require a battery to start them? Sounds like an early 250. I am guessing it is 6 volt and should not need a battery to start and run. The yellow and green wires should be the lighting and the rest should be for the engine. black should be earth I am not sure why the greens are together or the yellow is on the coil. If you are getting 9v from the yellow and black then this would power the lights and feed into the battery. I would disconect the greens and take the yellow from the coil. Put a voltmeter across a black and white and kick it to see if you get any power and try the same with the other black. If you do I would connect one black to the frame one black to the neg of the coil and the white to the pos of the coil. Make sure the coil is earthed properly just to make sure. If there is no power I would look at the points behind the stator to see how good or bad these are and change or adjust these and then try the first part again. Have a look HERE Link to comment Share on other sites More sharing options...
motorlou Posted October 5, 2009 Author Share Posted October 5, 2009 thankyou. i will try that this morning and get back to you. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted October 5, 2009 Moderator Share Posted October 5, 2009 How about a photo or two then? You might find this useful Here ...Paul Link to comment Share on other sites More sharing options...
motorlou Posted October 6, 2009 Author Share Posted October 6, 2009 well, went back out to the garage and connected the voltmeter to the black and white wires. when i kick it over it reads 6 volts or so depending on how hard i kick. i don't know if it is unreasonable to think that if the stator is putting out voltage the coil should spark unless it is bad or the stator is not putting out enough volts? how many volts should the stator be putting out when i kick this thing over? Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted October 6, 2009 Moderator Share Posted October 6, 2009 well, went back out to the garage and connected the voltmeter to the black and white wires. when i kick it over it reads 6 volts or so depending on how hard i kick. i don't know if it is unreasonable to think that if the stator is putting out voltage the coil should spark unless it is bad or the stator is not putting out enough volts? how many volts should the stator be putting out when i kick this thing over? I am not sure about the Voltage. I would say that as it is a 6v system that 6v is OK. The Yellow lighting circut would give more as it runs the lighting and feeds extra to the battery. Can you read the Ohms between the white and black wires? Is is about 10 Ohms? (Between the yellow and black should be about .18 Ohms) If you have 6volts and (assuming) 10 Ohms between the black and white the only things left are the timing and coil. Assuming that the points and condenser are ok as there is a volt reading and you have good earths connecting both black wires to the frame and the earth from the coil to the frame. Test the primary and secondary coil for Ohms. Primary 1 Ohm and Secondary 5.9 Ohms. Check the spark plug cap also for corrosion. Can you get hold of a 6v coil? to test this? Link to comment Share on other sites More sharing options...
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