66 305 dream-bike making a loud bang

[mschehen]

So I just got my latest project running again and it started making a loud bang that basically stops the engine. I checked everything I could think of and can find no reason for this to be happening. It will make the noise when you use the electric or kick start to turn over the motor but will not make it when you push the bike to do the same. I think the kick starter might be trying to engage when it should not be, however with the kick starter and right side cover removed it still makes the noise. I pulled the left cover as well and could not see anything wrong on that side either. I should also add that with the plugs removed the engine spins freely and does not make the noise. Any ideas would be appreciated.

[conbs]

Someone had a similar problem that I think turned out to be a screw that backed of the starter clutch and was hitting the case. Not too hard to pull the rotor to take a look.

[mschehen]

Turned out that the points had slipped and were not closing all the way. It was trying to fire on the exhaust stroke (backfiring) and the resulting clank was all three chains (primary,starter and oil filter) backlashing. Ran great for about an hour then something else went wrong. Back to the toolbox.
Thanks for the reply, I would never have made it this far without this forum.