The dreaded starter chain

[Sniper X]

So I have a 1984 CB700sc in for diagnosis and repair. Always wanted one of these, and may still get one.

Anyway, he brought it thinking it was a bad starter and asked me to pull the starter so he could go have it rebuilt. But, I did some cursitory checks and found out the starter isn't turning the motor because the motor won't spin in neutral. I verified this by removal of the side cover and trying to spin the engine with a ratchet. No joy at all.

How do I make sure this is the starter chain I've heard and read so much about without a teardown? Can I remove the stator and housing and see there?

What do i look for and where!

And, is there a complete tear down and replacement available or do I need a genuine honda CB700sc shop repair manual?

[mollusc]

You need a Honda Service Manual if you're going to own a Nighthawk.  End of story.  Most important tool in your workshop.
If you pull the starter and can rotate the teeth of the starter clutch in both directions with the bike in gear, the starter chain is toast.  Alternately, you can put the bike in second gear and try to bump it forward with the clutch lever released -- the vanes on the alternator should jump if the chain is intact.

[Sniper X]

You need a Honda Service Manual if you're going to own a Nighthawk.  End of story.  Most important tool in your workshop.
If you pull the starter and can rotate the teeth of the starter clutch in both directions with the bike in gear, the starter chain is toast.  Alternately, you can put the bike in second gear and try to bump it forward with the clutch lever released -- the vanes on the alternator should jump if the chain is intact.

the motor is locked up, won't turn in any gear and in neutral the crank won't turn. Starter chain complete failure?

[mollusc]

A locked-up engine could be anything, really.  There's no real way to tell if it's the starter chain or not, but that's kind of irrelevant since you would probably need to at least partially disassemble the engine for diagnosis anyway.

[slmjim n Z1BEBE]

Consider hydrolic lock if the bike has sat for a long period.  If the petcock was leaking, a cylinder might be full of fuel.  A long shot, but we've seen it happen to bikes & lawn mowers both.  Pull the spark plugs, insert small wood dowel as a dipstick of sorts, one cylinder at a time.  Check for liquid fuel each time.

If liquid fuel is noted, the motor might crank using the starter with the spark plugs removed. Don't try this indoors. Stand away from the plug hole & be prepared to deal with gasoline, as any liquid  fuel will be propelled out of the plug hole with some velocity.

Good Ridin'
slmjim & Z1BEBE

[mollusc]

I had exactly this happen with my plate compactor this summer.  Wouldn't turn at all.  I fussed around with it for quite a while trying to get to the end of the crankshaft thinking that the piston may have rusted in place.
Eventually, the nasty water in the cylinder squirted all over me when I removed the spark plug and pulled the cord.  Replaced the plug and it started on the next pull.

[dickdagger]

Take out those plugs and try to turn it over. I'm assuming he had it running at one point, then had this problem. If that's the case then there's a good chance it's hydro locked due to a float needle sticking open or the petcock leaking as well. If it still won't budge after the plugs are out, time to look deeper.

[Larry Fine]

Please keep in mind that, if there is fuel in a cylinder(s), there will also be fuel in the crankcase, which destroys the lubricating properties of oil.

So, please at least check the oil before spinning it much. If you can smell any trace of gasoline, it's probably too much to be safe for the engine.