The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: simmsy53 on 13.03. 2009 02:09
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Found this brass washer behind the thrust washer, but cant find it on schematics. Question is should it be there????
Thanks Simmsy
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Welcome aboard Simmsy, I havent had one of my clutches apart for some time but I cant remember there being any kind of brass washer in there. I'm fairly sure you have a "extra" part.
Brian.
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Nope, nothing like that in any of my BSAs. It would look nice polished up though! *lol*
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It is most likely a piece of hard brass shim stock put there to take up excessive wear.
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Is this the mutha you are talking about ??
http://cgi.ebay.co.uk/BSA-GOLD-STAR-B31-33-A7-AND-A10-GEARBOX-OIL-SEAL_W0QQitemZ400035494008QQihZ027QQcategoryZ108839QQssPageNameZWDVWQQrdZ1QQcmdZViewItem (http://cgi.ebay.co.uk/BSA-GOLD-STAR-B31-33-A7-AND-A10-GEARBOX-OIL-SEAL_W0QQitemZ400035494008QQihZ027QQcategoryZ108839QQssPageNameZWDVWQQrdZ1QQcmdZViewItem)
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Yep A10BOY that looks like a less mangled version of the mutha. Surely if its a gearbox oil seal though it would be in the gearbox side and not behind the clutch!! I too thought it may have been put there as a sort of shim.
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Here is a scan of the plunger clutch. The bit you have found doesnt belong so must have been put in there at some stage for who knows what reason.
The only thing that doesnt show in the scan for some reason are the two collets that go between parts 25 and 26.
It may be that a previous owner has had some sort of problem and has put a spacer/washer in for some reason. I would assemble the clutch without the chain and make sure the chainwheel turns freely and also the centre turns freely without any plates in and the centre nut done up.
These are very good clutches.
Brian.
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Just thinking the alledged shim could be the brass bit of the sliding plate that fastens onto the primary case behind the clutch, presuming that your variant has that plate.
All the best - Bill
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Is it a seal from the chaincase wall that has come loose?
Trev.
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As above, its definitely this seal, although why it was where it was who knows.
http://cgi.ebay.co.uk/BSA-GOLD-STAR-B31-33-A7-AND-A10-GEARBOX-OIL-SEAL_W0QQitemZ400035494008QQihZ027QQcategoryZ108839QQssPageNameZWDVWQQrdZ1QQcmdZViewItem (http://cgi.ebay.co.uk/BSA-GOLD-STAR-B31-33-A7-AND-A10-GEARBOX-OIL-SEAL_W0QQitemZ400035494008QQihZ027QQcategoryZ108839QQssPageNameZWDVWQQrdZ1QQcmdZViewItem)
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Brian,
You say these are very good clutches?
I have one of the things in my star twin basket case box of bits.
Are they much different to the 6 spring clutches being slandered in the beasts thread?
Do I need to start carrying a spanner and keep an eye out for suzukis?
cheers
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Olev,
In my opinion (I stress this is just my opinion) I reckon the plunger clutch is the best of the lot. There are basically three types of BSA clutches fitted to the A7/10's, the six spring as used in the plunger models, the "other" six spring (the type with six exposed springs and locknuts holding them and a horrible double row ball bearing thing in the middle) and the four spring as used in the later A10's. Both the plunger and the later 4 spring clutches are very good clutches and if in good condition will work very well and last forever. The reason I like the plunger clutch is because it has six springs as opposed to four and you dont need to put so much pressure on the springs which means you have a lighter clutch action at the handlebar. I would think the Suzuki clutches that have been mentioned would have 6 or maybe even 8 springs in them.
I hope I dont offend anyone here but the other six spring (locknut type) is not a very good design. I have them in my B and M series BSA's and have got them to work quite well but they rely on the chainwheel moving to one side to release the clutch plates. To shift a spinning chainwheel sideways goes against all engineering practices. Another problem is the bearing set up, firstly its very flimsy and the instant it gets any wear it will not work as it needs to.
So if you have a clutch for your A7 you can use it knowing it will do its job well. If I ever get a A10 that has one of the six spring locknut type clutches in it the first thing I will do is throw it in the bin and find a replacement. I am quite happy to use the plunger six spring or the later four spring in my bikes but I always use the best friction plates I can get (Surflex) and make sure everything is in perfect condition.
While we are on the subject of clutches, a lot of people dont realise how important the clutch is. A good clutch makes a big difference, most times if you have a bike that clunks going into gear or is difficult to change gear its usually the clutch that is the problem, a lot of gearbox problems are actually clutch.
There, I've had my little rant, now I'm happy........................................
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I agree with Brian they are good clutches if you assemble them how they are suppose to be. I have run these with no real problems other than worn plates and springs after years of service. I have seen problems with plates getting oil on them if the clutch dome cover is not done up tight with a good gasket.
These clutches also don't attach to the gearbox mainshaft with the taper that always has a sheared keyway when you find them at swap meeting(autojumbles). The plunger clutch has very thick spline (gear type) that never shears the gearbox mainshaft, better idea I don't know why they went away from it and why all BSAs aren't like it.
If you put new plates and springs with a good cover gasket and new rollers with fresh grease at the back you shouldn't have any trouble other than spring ajustment for years.
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Thanks Fella's,
very much appreciated.
cheers
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Hi Brian have you had trouble with the cheaper plates from ebay etc. I have just bought a few sets from UK that aren't surflex so I hope they are alright.
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Terry,
I've bought a couple of sets over the years that were not any good. I dont know what brand they were though as they didnt have any sort of brand name on them. The biggest problem with the cheap one seems to be they stick, even if the bike has only been sitting for a couple of days you need to free the clutch up before you start. Another problem is the thickness, the cheapy's are never the correct thickness, either too thick or thin so when you put the clutch together its either like a plate is missing or there are too many. I've been using Surflex for many years now and they are really good, a bike can sit for years and the clutch will not stick. I am yet to wear a set out, the ones in my B33 have done many thousands of miles are are still like new. I havent used them but a friend uses Barnett plates (from the USA I think) and he reckons they are really good too.
It really is worth the effort and expense to get a clutch to work properly, makes a big difference.
Brian.
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Gday,
After this discussion about a7 clutch plates, I decided to rummage through the basket and see what the star twin has. The plates have composite and metal inserts and look in reasonable condition.....except the gentleman who dismembered this machine some years ago decided to protect the plates by soaking them in oil. I assume the tin cover that screws onto the chainwheel is there to stop oil getting on to these plates. so, can they be saved?? I have seen pictures of a ratbag trying to stamp out a bush fire caused by burning oil off clutch plates. Maybe he should have done a bazza mckenzie.
cheers
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Yes, the plunger clutch is dry. That is its saving grace and makes it much more effective and eliminates sticking. I think if you soak your oiled plates in gasoline, they'll be fine. Also, the rear plain plate is much thicker than the others. Often, this plate has been replaced by a standard one and you get what Brian mentioned with the thickness funkiness. I also found a really thin (.030") plain plate in my Flash when I got it....I have no idea where that came from. With all the correct plates, it workes really well.
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Hello, everyone. I am having a bit of trouble with one of these earlier 6 spring clutches. Under load it is slipping, and make a hell of a lot of noise, metal on metal? Could this be because I haven't tensioned the front sprocket enough? I just did the nut up till I could get the split pin in, then backed it off so it was against the pin.
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G'day jimbo.
The cush nut MUST be done up to 65 ft/lb. There will be a gap between the nut and split pin. If the tensioner isn't done up enough the chain will rattle on it. Tension so the chain has no more than 1/2" deflection on the top run. Does it have the domed cover? Did you use car type oil in the primary?
Cheers
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g'day Jimbo- In addition to what Musko said; There will be a gap between the nut and split pin.
, I was lucky to find in my treasure chest, a washer that fits in that gap (had to enlarge th' 'ole & run a chamfer on one face to fit the contour of the nut though)...
It doesn't really do anything other than stop the nut from undoing far if it does break loose, and the spring-nut also holds the main bearing tight on the crank. I expect you'll hear a bit more about this *smile* *smile*..
There is another similar thread from Owain currently running that you may want to listen in on *beer*
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I've done the same duTch.
Cheers
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That split-pin arrangement seems a bit odd. Do you think maybe the original design for locking the shock absorber was different?
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That split-pin arrangement seems a bit odd. Do you think maybe the original design for locking the shock absorber was different?
Can't think I've seen one GB, but that pin is a bit feeble up against shock absorber being shocked, although I think maybe when set up right that should not happen?
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The split pin does nothing until the nut comes undone!
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Hi All,
Ignore the split pin, and the dopey lockwasher
Degrease the threads properly and apply some threadlock
There are loads of topics on the forum about the dangers of running the bike with the nut not tightened
and the various tools that can be used to tighten the bastard!!!
If the engine has been run for any distance with the nut loose, check the sump for broken up crankshims *warn* *problem*
John
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Having cleaned and applied threadlocker to shaft/cush drive nut, screw the cush drive nut on shaft untill it seats on the cush drive sleeve. Then tighten it as much as you can, if you cannot get a torque wrench on the nut torque it consider using a brass drift and hammer.