tdwhite Posted July 1, 2009 Share Posted July 1, 2009 Ok, well I just bought a DT100 a few days ago. It's orange with "100" in a black and white vertical stripe on the tank. It's mechanically all there, over the years previous owners have removed the headlight, turn signals, spedo, brake light, ignition switch. That doesn't bother me I'll never run it on the road. Otherwise it's all there. It's been sitting for a few years. Engine turns over fine, the carb opens/closes freely, the clutch, although it doesn't seem to disengage does pull and return freely. I have no spark. The woman that sold it to me tells me her husband thought it needed a new shear key between the crank and flywheel. I've never seen these go bad but, I'll check that out. In the meantime, I have a few trouble shooting questions. 1. How exactly would I go about testing the coil 2. How is the best way to break the flywheel nut loose? I'll get a puller but should I just have someone sit on the bike with the brake on in gear to get the nut loose? 3. How do I time the bike if not running? 4. Will this bike run without a battery installed? Thanks for any help! td Link to comment Share on other sites More sharing options...
Tylerman Posted July 1, 2009 Share Posted July 1, 2009 1- Testing method can be done with a commong multi-meter, either someone here should know how for your model or you can find manuals online (for a fee) 2- Get an impact driver, the nut should pop loose. The flyheel might have a specific puller to remove it, using a normal two or three leg puller might break it. 3- Most old two strokes from that era that I've worked on have fixed timing, in other words there's no adjusting necessary or possible without machining the crank. 4- Again most two stroke bikes from back then with a magneto/point iggy could be run without a battery, but I will defer to others on this board with this model to verify that as true or not. Post up some pictures. Link to comment Share on other sites More sharing options...
tdwhite Posted July 1, 2009 Author Share Posted July 1, 2009 I'll get some pics up ASAP. I paid $60 for her and would love to get it running to just putt around on. Link to comment Share on other sites More sharing options...
nayruf Posted July 1, 2009 Share Posted July 1, 2009 I'll get some pics up ASAP. I paid $60 for her and would love to get it running to just putt around on. @ to remove the fly/mag wheel I use a strap wrench like you use on an oil filter to hold the wheel in place. whilst undoing the centre nut. To pull the wheel off the crank I use the left hand screw thread puller that screws into the centre of the wheel. I only say this because I have seen both crank and mag wrecked all for the price of not getting hold of the right tools. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 1, 2009 Moderator Share Posted July 1, 2009 @ to remove the fly/mag wheel I use a strap wrench like you use on an oil filter to hold the wheel in place. whilst undoing the centre nut. To pull the wheel off the crank I use the left hand screw thread puller that screws into the centre of the wheel. I only say this because I have seen both crank and mag wrecked all for the price of not getting hold of the right tools. Like this to undo the flywheel nut, I place some fabric backed rubber strips under the chain wrench (Cut from industrial work gloves) thes protect the flywheel and give a good grip also. It would be wise to pull off the flywheel to check the woodruff key and also to give the stator a visual check over. As nayruf said, get yourself a proper puller for the job. Link to comment Share on other sites More sharing options...
tdwhite Posted July 2, 2009 Author Share Posted July 2, 2009 Thanks for the help guys. I can google this but does anyone here have any solid steps to rule out one thing over the other. Like what to check first, second, third for spark and how to actually rule them out? Here's some pics. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted July 2, 2009 Moderator Share Posted July 2, 2009 Ok, well I just bought a DT100 a few days ago. It's orange with "100" in a black and white vertical stripe on the tank. It's mechanically all there, over the years previous owners have removed the headlight, turn signals, spedo, brake light, ignition switch. That doesn't bother me I'll never run it on the road. Otherwise it's all there. It's been sitting for a few years. Engine turns over fine, the carb opens/closes freely, the clutch, although it doesn't seem to disengage does pull and return freely. I have no spark. The woman that sold it to me tells me her husband thought it needed a new shear key between the crank and flywheel. I've never seen these go bad but, I'll check that out. In the meantime, I have a few trouble shooting questions. 1. How exactly would I go about testing the coil 2. How is the best way to break the flywheel nut loose? I'll get a puller but should I just have someone sit on the bike with the brake on in gear to get the nut loose? 3. How do I time the bike if not running? 4. Will this bike run without a battery installed? Thanks for any help! td The easiest to answer is no.4 yes dont worry about a battery. Its only important for the charging circuit and the lights and as they share several components its safe to assume that you will never need either so the battery is not needed period. OG coverd getting the flywheel off, while its off replace the points, condenser and the plug and cap. Far easier and from the looks of the bike i would guess they are past it anyway. Bikes like that are not generally maintained like a road bike so consumables like the condenser and points will be in a bad way. The timing will only change if: some idiot has undone the stator plate thinking it will help ( unlikely) or the motor is split for a crank rebuild or such so i would forget about it for now. As for testing the ig coil get a multi meter and you should get around 6000ohms for the HT coil and around 1.7 ohm for the primary (stator) coil. And for your next question the points gap is 0.35mm or 0.014in. Link to comment Share on other sites More sharing options...
nayruf Posted July 2, 2009 Share Posted July 2, 2009 The easiest to answer is no.4 yes dont worry about a battery. Its only important for the charging circuit and the lights and as they share several components its safe to assume that you will never need either so the battery is not needed period. OG coverd getting the flywheel off, while its off replace the points, condenser and the plug and cap. Far easier and from the looks of the bike i would guess they are past it anyway. Bikes like that are not generally maintained like a road bike so consumables like the condenser and points will be in a bad way. The timing will only change if: some idiot has undone the stator plate thinking it will help ( unlikely) or the motor is split for a crank rebuild or such so i would forget about it for now. As for testing the ig coil get a multi meter and you should get around 6000ohms for the HT coil and around 1.7 ohm for the primary (stator) coil. And for your next question the points gap is 0.35mm or 0.014in. I did not read all of your earlier message, The lady that sold the bike on said that the shear key had possibly broke, If its the case that I had on my old DT twinshock, the woodruf key (shear key?) on my old bike kept getting cut in half by the inertia from the mag/flywheel, I kept replacing the key then I realised that the key is only there to locate the mag. and if the key was too tall in the crank slot or if the taper surface of the crank or mag has debris on it the key would keep shearing. so I cleaned all the contacting surfaces and made sure that the key did not actually stand too proud of the slot, this prevented the key from being driven by the mag and increased the surface contact area of the taper on shaft and crank, then hey presto no more sheared keys and all the spark's in the right place at the right time, I suggest to try it as you will be needing to remove the mag anyhow, so there will be no extra effort/cost involved Link to comment Share on other sites More sharing options...
Recommended Posts