QuestionHello, I just recently have come into ownership of a 72\´ Honda CB100. We changed out the gas, oil, cleaned the carbuter and the jets, replaced the spark plugs and the coil, and adjusted the points and valves. We finally got it to crank, but now when it get´s warmed up and we put it into gear and try to go, it bogs down on us and dies. Any help?
AnswerHailey, I hope you took the carb all apart for cleaning, as the air/fuel passages inside the carb body can be plugged off from sitting for so long.
I would suggest that you haven't checked the spark advancer function, which you can't really see unless you remove the points plate again. See if the points cam will move against spring pressure and then snap back to the retard point. If it is frozen or sticking, it needs to be cleaned and lubricated. BE SURE that you put the point cam back on the way it was, otherwise, the timing will be 180 degrees out and it will never fire up. Make sure that the point gap is about .014" and that they just OPEN at the F mark alignment of the rotor and stator marker.
These bikes had bad cam bearing designs, so if the camshaft is very loose in the head, the point gap will vary as the cam rotates, giving very inaccurate timing and poor performance.
Compression readings should be about 175 psi.
Is the clutch stuck? You may have to pull the clutch cover, remove the 4 springs and disassemble the clutch pack. Clean the fiber plates, wire brush the metal ones, make sure they are flat and then reassemble again. If the engine stalls when you put it into gear, then the clutch is stuck together.
Bill Silver
