Motorcycle Repair: 71 Honda sl125, cam bearings, inlet tubes

Question
I restored my old sl125 . The problem is it starts up fine and runs good . But when I drive it and it warms up not very long maybe 1/4 mile . It will not stay running and will stall . Then it will not start if I let it sit for a little while it will start right up again . But it will do the same thing after it warns up again . Before I took it apart it behaved the same way . When I put it back together I put in a new plug,points,condencer and rebuilt the carb . I also switched the coil from another 125 ( not new ) But as I said it is still acting the same way .  Please Help !  Thanks Andy

Answer
Andy, I would check the petcock passages and inlet tubes for corrosion or buildup inside, then look at your gas cap. There are small venting holes at the edge of the gasket area and they get plugged up when the bikes sit for years with old fuel in them. I assume that the tank is clean and the fuel line has been replaced, along with correct specs for float level and tune-up items.

You can try to drive the bike until it stalls and then take off the gas cap. You may hear the vacuum release or at least the bike should start up within a minute or so.

Do check the camshaft for looseness in the cylinder head. The cam bearings are not very sturdy and the cam wobbles around, affecting the ignition timing and coil saturation.

Bill Silver