Motorcycle Repair: Wiring and engine dying, weldons, overflo

Question
Hello, I own a honda 55, from the 1960's. It is a trail bike. The bike has to have the choke on in order to start, then only runs for a few seconds with the choke on. If you let the choke off it will die. There is a spout on the left hand side when riding, that I do not know what goes to. It dripped all of my gas out. Also, when the engine is on, if you turn the key to have the lights on, the engine dies, that is if I can get it running that long. The bike is the same as jeff weldons honda if that helps, pretty much need help with the wiring and why its dying if that is possibe.

thanks, dennis

Answer
Dennis... First, always check the valve clearances. Only .002" cold, but vital to these engines. Hopefully you have compression readings around 100psi. Then, go to the magneto, clean the points and be sure that they are opening at the F mark alignment with the mark on the case.

NOW we can address the carburetor. Did you take it apart and clean it yet? Assuming you have good compression and spark timing correct, the idle jet needs to be clean in order for the motor to idle steadily. If you screw the idle speed screw in all the way, trying to get it to idle, it starts to get fuel from the needle jet instead, but it still needs the idle mixture supply to make that transition to part throttle.

I have wiring diagrams for C100 and C102, but not C105T, which should be similar to C100. Contact me through my website www.vintagehonda.com and I can email them to you.
Pure magneto ignitions don't need a battery to run the engine, so turning the lights on shouldn't affect it, other than the use of the lighting coil in the magneto.
If the bike is barely running, then that may be enough to cause it to stall out from just the added electrical drag on the flywheel.

The carb and fuel system must be clean, so get it apart, clean all the jets and passages and check the float valve for wear and or damage or dirt. Once you get the carb to hold fuel properly and not spit out the overflow tube (dirty/worn float valve), you should be able to get it running properly again... after you check the above items.

Bill Silver