Vintage Dirt Bike Q & A

I just got a 74 MT250 in a trade and it is in really good shape except for a missing tank and it does not fire. I printed out the wiring diagram on this board and checked all the switches and I can connect the meter to the leads of the mag and kick it over and see voltage on the meter. What role does a battery play in the over all picture. Does the bike just need it when it isn't running and what(where) is the bridge on the diagram for and located? After the switches I checked the coil and it does not read open but I don't have anything to tell me what the ohms should be for this stuff. I have a service manual on the way but I would like to make sure this bike will run before the trade gets set in stone. Thanks any help would be appreciated.

Paul

I have one. The ignition circuit is the same as a lot of other Hondas of the period. The exciter coil, points, and coil, are a single circuit that is completely independant of the battery/lights etcetera. To make them run, you only need the black with white stripe wire coming out of the case jumpered to the coil w/o anything else in the circuit. I believe the ignition switch just grounds the exciter coil so you would have to pull that lead.

Make sure the points are set right and the flywheel is indexed and it should fire.