how the heck do you compress the engine cush drive spring?
The ol' M20 is coming together, and I've got the transmission back in and have the primary off. I've replaced the engine/primary gasket and I'm ready to button it all up. But... how do you compress that spring on the engine cush drive enough to engage the threads on the nut? Anyone got any tips, they would be very appreciated.
Re: how the heck do you compress the engine cush drive spring?
Hi Kevin..I do it with two pairs of snipe nosed (pointed) mole grips (Vice grips in the U.S.?)..you can catch on the edge of the spring coils and lock them together to compress the spring..Watch out if they come off though..they take off! Some books tell you to wire the spring coils together but I have never found this a good method..Ian
Re: how the heck do you compress the engine cush drive spring?
I have a different method, I put the machine near a wall, block of wood between the timing side & wall (to stop the bike moving that way) then a square of half inch plywood about 4" square, I put the wood over the nut & push & turn as soon as I feel it contact & it always seems to work, quickly get a few turns on it immediately though... Give it a go if you havnt got the vice grips.
Re: how the heck do you compress the engine cush drive spring?
According to BSA Service Sheet 607 “The engine shaft cush drive can be replaced by hand, without the need for special tools to compress the spring”. In those days, men were clearly men!!
But (just for the young apprentices?) there was a special tool 61-1822 for holding the spring compressed after squeezing it in a vice. I’m sure I’ve seen reproductions up for sale, although easy enough to make your own.
Re: how the heck do you compress the engine cush drive spring?
I,ve found in the past that the engine cush drive spring can be done by palm of the hand pressure....the single clutch spring on the other hand is always difficult even with the compression tool!!
Re: how the heck do you compress the engine cush drive spring?
I can't post photographs because I am at work right now, but I have made 2 of a sort of "C" clamp by grinding the edge of two pieces 1/2" x 1/8" flat steel (or any handy size bit of steel)
The gap of the inner faces of the "C" is just slighly larger than when the spring is fully compressed in a vice.
I compress the spring right up in a vice, then slowly release it until the C clamps take the spring pressure.
Then put it on the shaft and get the nut started. Once the nut is started the clamps be knocked off.
WEAR EYE PROTECTION incase they ping off before you ready
It works for me, but I dont want to be responsible for any one eyed WM20 riders
Re: how the heck do you compress the engine cush drive spring?
Hi, Is there any chance of seeing pictures of these different approaches? I'm not in that part of my bike yet but when I do, the pics will be invaluable. And for those in there now, even better!
Re: how the heck do you compress the engine cush drive spring?
Great to see the ol' thread still has life. Just finished putting a new piston in the ol' girl. Had a partial seizure due to the sump plate springing a leak while I was tail end charlie on a ride through the Hollywood Hills. The bike still has a lot of life in 'er.