Motorcycle Repair: Coil ?, 650 yamaha, bill silver


Question
hi,hey i have my 650 yamaha special there and its been a while and i decide to start it but,ok i put gaz on spark and crank it he just start after he stop and the 2 coil there was so hot ??? what do you think about that ???

Answer
Billy, I am not a Yamaha expert. I think that there were various versions, most with points and condenser and maybe some with CDI ignition...? You didn't mention what year the bike was.

Coils do get hot when you are cycling them on and off during cranking and running time.

You have to use clean spark plugs to check for a good spark, so you know if the problem with starting is really ignition or fuel. In most cases, the bikes that sit for awhile need carburetors cleaned out and the idle jets cleaned. The bikes may start with the choke, but then will die when you take the choke off again, due to lack of fuel in the idle circuits.

If the bike has points and condenser, the points need to be cleaned and adjusted so they will turn the coils on and off, properly. If the coils are grounded through the points all the time or if electronic components are not functioning then the coils will get hot enough to fail.

Bill Silver