Author Topic: A7 clutch (plunger)  (Read 4643 times)

Offline simmsy53

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A7 clutch (plunger)
« on: 13.03. 2009 02:09 »
Found this brass washer behind the thrust washer, but cant find it on schematics. Question is should it be there????
Thanks Simmsy

Online Brian

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Re: A7 clutch (plunger)
« Reply #1 on: 13.03. 2009 08:46 »
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.

Offline LJ.

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Re: A7 clutch (plunger)
« Reply #2 on: 13.03. 2009 09:25 »
Nope, nothing like that in any of my BSAs. It would look nice polished up though!  *lol*
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

Online BSA_54A10

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Re: A7 clutch (plunger)
« Reply #3 on: 13.03. 2009 12:43 »
It is most likely a piece of hard brass shim stock put there to take up excessive wear.
Bike Beesa
Trevor

Offline A10Boy

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Andy

1958 Super Rocket
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1974 Kawasaki Z1a
Yam XJR 1300

Offline simmsy53

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Re: A7 clutch (plunger)
« Reply #5 on: 13.03. 2009 19:12 »
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.

Online Brian

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Re: A7 clutch (plunger)
« Reply #6 on: 13.03. 2009 21:38 »
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.

Online bsa-bill

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Re: A7 clutch (plunger)
« Reply #7 on: 13.03. 2009 21:51 »
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
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline trevinoz

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Re: A7 clutch (plunger)
« Reply #8 on: 13.03. 2009 22:21 »
Is it a seal from the chaincase wall that has come loose?
  Trev.

Offline A10Boy

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Re: A7 clutch (plunger)
« Reply #9 on: 13.03. 2009 23:21 »
Regards

Andy

1958 Super Rocket
Plus
1974 Kawasaki Z1a
Yam XJR 1300

Offline olev

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Re: A7 clutch (plunger)
« Reply #10 on: 13.03. 2009 23:51 »
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


Online Brian

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Re: A7 clutch (plunger)
« Reply #11 on: 14.03. 2009 00:30 »
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........................................

Offline terryk

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Re: A7 clutch (plunger)
« Reply #12 on: 14.03. 2009 00:34 »
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.  
1950-53 A10 rigid/plungers, 1958-61 A10 super rockets, 1947-50 A7 longstrokes, 1949 Star twin,
1951-54 A7 plungers, 1940s M21, WDM20s,
1948-50s B33s rigid/plunger/swingarm, 1948-50s b31s rigid/plunger/swingarm

Offline olev

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Re: A7 clutch (plunger)
« Reply #13 on: 14.03. 2009 01:22 »
Thanks Fella's,
very much appreciated.
cheers

Offline terryk

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Re: A7 clutch (plunger)
« Reply #14 on: 17.03. 2009 14:28 »
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.
1950-53 A10 rigid/plungers, 1958-61 A10 super rockets, 1947-50 A7 longstrokes, 1949 Star twin,
1951-54 A7 plungers, 1940s M21, WDM20s,
1948-50s B33s rigid/plunger/swingarm, 1948-50s b31s rigid/plunger/swingarm