WM20 frame spacers around engine and gearbox plates.
I've just bought a WM20 in bits in boxes.
I need help with all the spacers that go around the engine and gearbox plates. I do have some obviously correct ones.
Does anyone know of a drawing that gives the dimensions of the spacers. There is one set of spacers to go below the gearbox rear. Another set to go at the front of the gearbox. Any spacers at the very front at the bottom of the downtube?
I'm in the UK in a place called Potters Bar.
Any help very much appreciated... Jon
Re: WM20 frame spacers around engine and gearbox plates.
Henk, that must have been a world record for speed of reply..thanks.
So there are no spacers at the front of the frame.
You have supplied the dimensions at the back.
Do you have the size of spacer in the middle on the right hand side?
I need to get these right as there is a small repair required to the rear part of the frame.
Thanks again Jon
Re: WM20 frame spacers around engine and gearbox plates.
The gearbox plates run parallel with the righthandside lower rearframetube, so the length of the spacer just behind the engine has the same length of the spacer behind the gearbox on the righthandside. Which is 40 mm.
Also the top RHS frame tube which goes to the saddle is in the same plane as the lower.
Re: WM20 frame spacers around engine and gearbox plates.
Morning all,
I would be most grateful if anyone who has the above information could please forward it on to me. I've looked in the technical section and can't find it.
Thanks
Alwyn
Re: WM20 frame spacers around engine and gearbox plates.
Anyone can submit information for inclusion on the 'Technical Section' but sadly it is an underused and under supported resource....It a shame more people don't contribute to, as well as take from, the website generally as it would further improve the experience...Ian
Re: WM20 frame spacers around engine and gearbox plates.
This is what I first thought Ian, but all the information I can find points to it being the other way.
There would be more offset on the left hand side due to the hub.
I await to be prove wrong.
I've just fitted my rear chain and the sprockets looked at each other close enough?
Re: WM20 frame spacers around engine and gearbox plates.
I think Mark is correct - here is a pic of a set I made for someone a while back. There is quite a kink where the brake stay is fitted and that is where I have the 1 3/4" one fitted in this photo.
The shorter one is 1 9/16".
Re: WM20 frame spacers around engine and gearbox plates.
['I stand corrected if that is the case!...']
Likewise...I've never fitted them that way over many M20, M21,M33 and B Series rebuilds without any apparent issues, in fact I recently fitted them to mine...Taking into account the 'flexibility' of the M20 rear frame I guess I may just have been lucky!...
Forunately it's not too late to reverse the order of assembly if it turns out to be incorrect...Ian
Re: WM20 frame spacers around engine and gearbox plates.
From a previous post on the subject...Info. from Neale Gentner....It's beginning to look like I've been wrong most of my life...:laughing: ...Ian
[ '66-4601 Chainstay bridge distance collar, 3/8” clearance bore x 1.595” o'all, waisted, right side, (shortest of the 3 x 3/8” bore frame spacers) common to all 1937-1960 500cc & 600cc rigid frame singles 1 per machine.
66-4602 Chainstay bridge distance collar, 3/8” clearance bore x 1.763” o'all, waisted, left side, brake stay is fitted between this spacer and left side frame lug, combined extra length of both makes up for offset of rear frame which accommodates chain & brake etc, common to all 1937-1960 500cc & 600cc rigid frame singles. 1 per machine.
15-6240 Chainstay bridge distance collar, 3/8” clearance bore x 2.500” o'all, waisted, fits between rear engine/gearbox plates, common to all 1937-1960 500cc & 600cc rigid frame singles. 1 per machine' ]
Re: WM20 frame spacers around engine and gearbox plates.
The easy reminder is that the RHS spacer has the same length as the thick one in front of it as the gearboxplates should run parallel with the RHS bottom frame tube.