Z1OwnersClub GB

In the absence of the special tool for locking the sprocket does anyone have any suggestions regarding locking it whilst installing the locking nut?

Also, the shop manual states torque should be 87 - 108 ft-lbs. What do you guys reckon is the minimum acceptable as 108 is a hell of a lot on a bike?

Without the sprocket holding tool, or if you're using a front sprocket without the holes in it for the tool to locate in, I would suggest the most obvious method would be to fit your new engine sprocket, (or old one if just refitting existing parts) & fit the tab washer followed by the nut & nip it up as tight as you can, even finger tight will do at this point.
Refit your chain, then put the bike in 1st gear. Get a willing helper to sit on the bike with the bike on the ground, not on the side stand or main stand & apply both brakes.
You then tighten the engine sprocket nut to the required torque.
Torque wise I tend to go with a mid point figure for parts like this. At the end of the day providing the nut is tight & the tab washer is correctly locked against the nut it will never come undone.

Stick a long screw driver through the chain from above just behind the front sprocket, make sure the screwdriver goes through a link at the bottom This will lock the chain and sprocket whilst you tighten the nut.

I hope this makes sense.

That’s a good suggestion, I’ve been pondering the same problem. I was also considering jamming a rag between the chain and sprocket. The engine sprocket on my Sportster got tightened up that way, and it’s still there thousands of miles later.

I couldn’t borrow a torque wrench that went high enough so I did it by feel, tight as f*ck, basically.

just wedge a piece of broom stale between the sprocket & the chain