Undoing the alternator nut (1965 B40F)

Phil C · 15 Feb, 2021, 17:58

I can't remember how I dd it last time. What is the best way to stop the crankshaft turning to enable me to undo the rotor nut? Thanks. Phil

Pete Gill · 15 Feb, 2021, 18:19

If the engine is in the frame and the primary chain and clutch fitted lock the back wheel with the the foot brake.
Pete

Phil C · 15 Feb, 2021, 18:25

I tried that. Will try again.

berniej · 15 Feb, 2021, 18:29

In 1st gear....

Pete A10 · 15 Feb, 2021, 18:50

Why do you want to undo the rotor nut? To see what it looks like from the other side?

Phil C · 15 Feb, 2021, 18:53

Quote from: Pete A10 on 15 Feb, 2021, 18:50
Why do you want to undo the rotor nut? To see what it looks like from the other side?

Taking the clutch off to look for the source of a leak.

Phil C · 15 Feb, 2021, 18:56

Working on my own. Bike in first gear. Sitting on it (to keep it stable), pressing hard on brake pedal, trying to undo the nut with a socket wrench using just my left hand. A bit awkward, but anyway, the engine turns. Any other ways? Phil

Phil C · 15 Feb, 2021, 19:19

Also tried positioning myself at the side of the bike, pressing the brake pedal, so that I have two hands for the wrench. But still can't stop the engine turning.

LightningAndStarfire · 15 Feb, 2021, 19:45

I used an air wrench on my B25. Also worked on my Yam SR500.

Phil C · 15 Feb, 2021, 20:07

I don't have air. Maybe I need to take out the clutch plates first and then use a clutch locking tool? I made one a couple of years ago - might not be solid enough, but one way to find out.

Pete A10 · 15 Feb, 2021, 20:22

Get someone else to hold the back wheel, altenatively lock the back wheel by roping it to the garage door - much more leverage than the brake. Good fitting socket and handle - hit the handle with a hard sharp knock with lump hammer - same effect as an impact wrench. Other question is whether the clutch is slipping - if not then there should be enough resistance generated to be able to free off the nut.

Phil C · 15 Feb, 2021, 20:52

Well I was sitting on the bike so that the back wheel was pressed against the floor. Not sure I could hold it any more firmly than that. Re roping wheel to garage door - would that not damage the spokes when I tried to tighten the nut?

Willie Dee · 15 Feb, 2021, 21:40

You do not have air but a lot of good battery impact guns out there now. Got a mate you can borrow one off of??

Mike Farmer · 16 Feb, 2021, 09:50

Try locking up as best you can and use an impact driver. One or two good whacks should do it.

Mike

Phil C · 16 Feb, 2021, 10:51

I quite fancied that idea. Wife sitting on bike, me pressing on brake pedal and whacking impact driver with club hammer. No joy. Phil

News:

Undoing the alternator nut (1965 B40F)