1982 honda cb900 dies when hot and will not start until it cools down?

Question

My 1982 CB900 Honda has left me stranded twice in the last month. Both times I had driven about 12 miles and then it suddenly lost power and died while at a stop light. When I hit the start button, nothing happens, not even a click. There is still power as the lights all work. I replaced the battery the first time. The second time I did not replace the battery and it started right up after sitting for two hours. I expect it is an electrical problem caused by heat but have no idea where to start looking. Any help will be greatly appreciated.

Thank you.

My local Honda dealer said they will not look at this old of a bike until after the summer season is over. (Guess they consider old bikes a hobby)

Answer 1

Most common problem is a defective coil.

When coils are on the way out - the internal windings expand and separate - when the coil cools down, the windings contract and make contact again.

Carry a known working spark plug with you.

When the engine stops running, pull off the spark plug caps and check for spark.

Insert the good plug into a spark plug cap - lay the threads of the plug against the engine and try to start the engine.

If there is no spark on any one of the plug caps, have that coil checked out.

The "spark units" go bad on that model, but it's unlikely they would work intermittently.

Still....they should be checked out.

http://www.motocom.com/motorcycles/

Answer 2

Any chance you can get out of this bike? The CB900 was not one of Honda's best moves. Its old, not the best as far a reliability and never did preform well. If you have an antique affection for it that is one thing. If you are trying to ride it as transportation you will be disappointed. If you have designs on restoration you won't mind waiting till end of summer. Why not try another dealer. I'm sure parts for this bike will be a hassle. I'd sell and move on.

Answer 3

Does your bike use electrical relays?  You know, the same kind of little cylindrical thing you find in the fuse box of a car?  If so, one of them could be heating up with use.  If you have them, they should be cool to the touch when in use, if they feel hot or warm, they're going bad.  My bike uses them and I've had to replace several.

If not, check the electrical connections where the fuses attach.  Look for any green or white stuff on the connections and clen them up.

Otherwise, it's going to be time to get a shop manual with a wiring diagram and start tracing down the ignition system and checking connections.  Since the lights work but no click at the starter, you'll be going from the ingition switch through the kill switch and to the ignition coils.  Again, look for overheated or corroded connections.  Pull the connectors off, clean if necessary, apply dielectric grease and put them back together.

Answer 4

http://www.cb750c.com/modules.php?name=F...

That forum will provide you loads of advice and help.