Topic: SHould I be able to rotate crankshaft counter-clockwise?

[neudl]

WHen I reassembled the top end, the crankshaft would not turn.  After pulling everything apart, it turns out the camchain was caught up on something.  I now have the head back on, and the crankshaft turns clockwise, but not counterclockwise.  I can't recall whether it would rotate counterclockwise before.  Anyone know?

[markjenn]

WHen I reassembled the top end, the crankshaft would not turn.  After pulling everything apart, it turns out the camchain was caught up on something.  I now have the head back on, and the crankshaft turns clockwise, but not counterclockwise.  I can't recall whether it would rotate counterclockwise before.  Anyone know?

I've heard some folks recommend avoiding rotating the engine backwards, but I've never heard of one that can't be rotated backwards.  If it's physically obstructed from turning backwards, that sounds like a problem.  Is it making any strange noises when you rotate it forward?

- Mark

[crazypj]

It should turn but will be much harder than turning in 'normal' direction as the starter motor (including all the reduction gears) will be engaged and have a high torque. its not recommended as cam chain tensioner could get damaged.
 I've seen a situation where the chain wasn't tensioned properly and turning engine backward made it jump a tooth or two  (then it bent a bunch of valves when guy hit starter button)
PJ

[Raul CB750K1]

It should turn but will be much harder than turning in 'normal' direction as the starter motor (including all the reduction gears) will be engaged and have a high torque. its not recommended as cam chain tensioner could get damaged.
 I've seen a situation where the chain wasn't tensioned properly and turning engine backward made it jump a tooth or two  (then it bent a bunch of valves when guy hit starter button)
PJ

The chain must be VERY loose to have a tooth jumped out of place

[crazypj]

Turning it backwards compresses tensioner blade

[neudl]

So with the tensioner in I should not expect it to turn counter-clockwise?   I want to make sure that if there is a problem that necessitates me pulling the head back off, I do it now instead of after I have the valve cover and carbs back on.

[lordmoonpie]

It should turn both ways no problem although backwards will compress the tensioner more so may be slightly more resistance tan forwards. It will go though so it sounds liek you've got somthing really wron inside. I had a similar problm recently on my CB450 - traced it to a shim on the CR gearbox. If I remove the shim it works fine, leave it in and it locks the crank.

You could have one of many problems but it's definitely a problem...get it apart now!

[neudl]

Thanks - It's back apart.  I think the problem is a bent tensioner