Clutch fitting help

[shallam]

Hello
My 1932 3 speeder has a clutch which objects to be held for long. As a result I have to engage neutral before coming to a stop otherwise the clutch drags and the engine stalls. I have been living with this for a couple of years but last summer at Abbotsholme I bought a new set of clutch plates from our excellent spares scheme.
For some reason I am unable to access the technical forum so I was wondering if their is anywhere that gives an easy to follow description of how to fit new clutch plates. I have the technicalities but find it hard to locate anything.
Also a friend who is not familiar with Scotts thinks the Scott clutch is very similar to a Velocette. Did Scott make their own or is it indeed a Velocette mechanism?
As you may have gathered from my questions I am a novice when it comes to the mechanics of a Scott.
Any advice/info would be greatly appreciated.
Regards
Steve

[Dripfeed]

Hello Steve its not a velo clutch it is Scott.(ner the twain shall meet ) Some Scotts have had Velo gear boxes complete with Velo clutch fitted but that’s another story. The Scott clutch is straight forward if replacing just the plates try not to let the clutch sprocket come towards you when you undo the clutch springs it runs on rollers that are best kept in place when you have replaced the plates and springs ajust the spring retaining nuts so as to get the outer pressure plate to run true with the clutch handlebar lever held in and operating the kickstart pedal . The book of the Scott from the 1930s has a page or two with all the gen .others greater than Iwill be able to gen you up. Regards D F.

[BRIAN MARSHALL]

Hello Steve. From your description of the clutch drag problem, I doubt that changing plates will cure it, and it may even make it worse, as the new plates will be thicker, and less likely to disengage cleanly. Your problem may be a simple one, just needing adjustment of the cable, or you may have a badly worn quick-thread mechanism, or even a loose clutch retaining nut. Try adjusting the cable first. The adjuster is about half way along the cable, usually under the tank. Slacken-off the locknut and unscrew the halves of the adjuster, so as to lengthen it, but make sure that you still have about an eighth of an inch of free play at the handlebar lever end.
If that doesn’t cure it, let us know !
Brian

[shallam]

D.F. and Brian
Thanks for your help.
I have found the instructions from the 1930s booklet. Look simple enough …hmmm but we are talking Scott!
Brian, I will check out your suggestions first.
I will be doing this next Saturday and will report back.
Steve

[pplatt]

Brian, you seem to be a source of much information when it comes to Scott mechanicals.

Have you ever thought about writting a ‘Haynes Manual’ for Scotts? I’d buy a copy 😀

-PP

[BRIAN MARSHALL]

Well I am writing, (slowly), a Scott book, but it is really intended to be a Scott history, rather than a “practical tips” sort of thing, but I might be tempted….. I do however get a horrible sinking feeling that finding a willing publisher for the book may be very difficult. Ivan Rhodes, the Velocette guru, told me of publishers that have let him down badly some years ago, and I suspect that I will meet similar problems. Spending months on extra chapters, then having an editor put them in the bin, would be too much to bear !
Brian

[pplatt]

Self publishing could be an option. Even if you just did a Pdf file I’m sure it would sell.

Put me down for a copy of your Scott history book too!

-PP

[shallam]

A Haynes style manual is just what we need! I have often thought it would be good to have videos – You tube style of “How to …….”

[shallam]

Right then. I looked at the clutch yesterday. I managed to get the clutch plates out – the plates with friction corks were all covered in a hardened dirty crud. There is very little wear on the corks and it looks like most of the clutch plates were not doing much as the clutch plate tongues were such a tight fit in the casing due to the crude build up. Also the 3 thrust pins were not pressing evenly and so they are now not the same length.

So I will replace the clutch plates with new ones clean everything up so they move freely. Fettle the thrust pins so they do their job properly. Replace magneto chain and drive chain as they were both worn.
What should I do about the cork friction pads which go through both sides of the clutch sprocket, they are covered in the same crud as everything else so it would be silly not to replace these when changing the rest. Is it possible to have modern material bonded to it? If so who can do it and what spec should it be?

By the way to get the clutch sprocket out I had to undo the gearbox to allow it to be slightly raised as the sprocket wouldn’t clear the base tray. One good thing the roller bearings stayed in place.

Help and advice appreciated.
Steve

[BRIAN MARSHALL]

Hi,
Your best bet is certainly SAFTEK, as advertised in most of the classic/vintage magazines. If you send them the clutch sprocket they can replace the inserts with rings of modern friction material, all at a very reasonable cost, and with a very fast turnaround too. When you look at the clutch sprocket with the inserts removed you will think that there is VERY little metal left between the holes for the friction rings to be bonded to, but fear not…. They first fill all the holes with some sort of heat resistant epoxy resin type stuff, face it all flat, and then bond the new rings to that.
However, if your cork inserts don’t look worn, why bother ? A good clean up, and making sure that the tongues on the plates are free in the slots in the clutch drum, should restore everything to sweetness and life at no cost.
In the past couple of years I had what I can only describe as a clutch overhaul/rebuilding frenzy, with boxes of cream-crackered and dismantled old clutches (about 15 !), all rebuilt and most sold to members. I do have a handful left, ready to fit and go, including Flyer, TT Rep (banded), and Sprint Special (twin sprocket), types. Exchange price would depend on the condition of your unit, especially the state of the sprocket teeth, and any wear corrugations on the sides of the slots, either of which greatly devalue your unit. My contact details are in every Yowl, under Eastern Section Details.
Brian

[shallam]

The clutch sprocket is with Saftek. Brian thanks for the offer of a replacement clutch but my unit is in fair condition so will stick with it.
What happens when you run out of refurbished units? Is this another item for the club to consider having made?

[BRIAN MARSHALL]

The only really tricky item is the basket/sprocket, as when the sprocket teeth are worn there is precious little room available to grind them off and then weld/braze on a replacement sprocket ring. Indeed when the teeth are only slightly worn, the side-plates of the primary chain soon start making contact with the body of the basket, if it is a ‘banded’ type, as on TT Replicas, Sprint Specials, and 1931-1933 Flying Squirrels. I have never tried to do that job, and one or two old baskets with worn or broken teeth sit forlornly on my shelf. Many years ago, when the sprocket repair king Roger Maughling was still alive, I showed him one of them…. There was a slow shake of the head, rather than the nod I was hoping for.
Brian

[gammakeith]

Oh. I now feel fortunate that my basket teeth are in good condition. I did wonder when looking at it yesterday how the heck you changed the sprocket and I now know 😥 I guess its best to make sure the chain is replaced regularly to avoid the risk of wearing the teeth?

Keith

[BRIAN MARSHALL]

Serious wear seems to be fairly uncommon, unless the bike has done a humongous mileage, as they are hardened steel and very tough. Chipped and broken teeth are more common, and due I suppose, to stones and grit getting in there. In the past I have repaired the odd broken tooth by building it up with sif-bronze weld, and then VERY carefully reshaping it by hand. I have also filled any wear corrugations in the sides of the slots in the basket with sif-bronze too.
Brian

[shallam]

The gearbox is now out as the bolts for clamping the gearbox to the undertray are not a very good fit . I may have to fit helicoil inserts.
My question concerns the ball thrust pack It is fitted with roller bearings rather than the original ball bearings, is this ok as an alternative?
What should the thrust pack height be?

[Author]

Posts