Where to hold crank while tightening crank drive sproket L/S

[joep]

I have heard a few methods of performing this task , I prefer to hold the crank some where while tightening any crank nut ( if possible ) , the engine is in the frame hooked up to chain ect , what is the preferred and correct method and and what is the proper torque figure ( unable to find in the factory manual ) ?
Thanks in advance !

[DJM]

I've never seen a torque figure for the crankshaft nut either!

All the manual says is 'tighten the 20mm nut securely'

Just tighten it as much as you can and then some more, I'm confident that you won't strip the thread! Use a new tab washer and make sure that you get the bevel washer the right way up.

As for holding the crankshaft while you tighten the nut I place a piece of soft metal, aluminium or brass between opposing teeth on the clutch and engine sprocket.

By opposing I mean one tooth below the centre line of the crankcase and one above. As the crank tries to turn, so will the clutch as the primary chain is in place at this stage.

When you tighten the nut the 'opposing teeth' will be trying to move towards each other but obviously can't as your piece of metal is stopping them. The crank is effectively locked solid and you can put as much pressure as you wish on the crank nut to get it really tight.

Purists may not like this method but it works for me. Another way is to put a piece of rag between one or other of the sprockets and the primary chain but that is nothing like as effective.

[G-Man]

DJM

Good method. It's a good idea to avoud doing anything that will twist the crank on the shafts. They are surprising 'flexible'.

G

I've never seen a torque figure for the crankshaft nut either!

All the manual says is 'tighten the 20mm nut securely'

Just tighten it as much as you can and then some more, I'm confident that you won't strip the thread! Use a new tab washer and make sure that you get the bevel washer the right way up.

As for holding the crankshaft while you tighten the nut I place a piece of soft metal, aluminium or brass between opposing teeth on the clutch and engine sprocket.

By opposing I mean one tooth below the centre line of the crankcase and one above. As the crank tries to turn, so will the clutch as the primary chain is in place at this stage.

When you tighten the nut the 'opposing teeth' will be trying to move towards each other but obviously can't as your piece of metal is stopping them. The crank is effectively locked solid and you can put as much pressure as you wish on the crank nut to get it really tight.

Purists may not like this method but it works for me. Another way is to put a piece of rag between one or other of the sprockets and the primary chain but that is nothing like as effective.

[mike in idaho]

I wouldn't wedge something between the sprocket teeth, that's a good way to bend a shaft. Put it in high gear and hold the alternator bolt with a socket.

[joep]

How about while having the transmission in high gear with the rear brake on and holding the mag rotor with a strap wrench ( smooth metal oil filter wrench ) ? I have the right cover anyways : > )

[DJM]

As I said, my method may not appeal to everybody, I can only say again that it works for me and I haven't bent any shafts yet.

Putting the engine in gear and holding the rear brake is only possible once the engine is fitted in the bike and really only works on a more or less fully complete bike. Unless you have very long arms it will also require assistance from a second person to hold the brake on.

I do it the way I do because it is a one man job and the engine can be fully built while on the bench in the workshop, particularly useful if you are just rebuilding an engine for someone else.

[mike in idaho]

If you have a strap wrench on the rotor there is no need to hold the brake.