Author Topic: Plunger clutch not releasing  (Read 2363 times)

Offline anjimehra

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Plunger clutch not releasing
« on: 28.06. 2010 13:47 »
edit: aplit from Re: 1952 bsa plunger (broken rocker spindle)

Hi guys
Got the kickspring. Took her out for a longish run. She ran fine except for the clutch.  I soaked the friction plates in oil before assembling & didnt bolt on the cover for the dry clutch.In other words, it is now operating as a wet clutch.
The problem is that there is no slippage but the plates are not releasing, with the result she creeps forward no matter how I adjust the clutch. I think whats happening is that the outer pressure plate is being pushed out but the rest of the plates do not separate. Iam using engine oil 20/50 in the primary cover. Do I need to use a thinner oil? or just keep looking for the dry plates ( there are some available here but they dont fit !!!!! ). Anybody else tried running a wet clutch on the plunger?
Any help would be appreciated
 Take care, Anji

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Re: Plunger clutch not releasing
« Reply #1 on: 28.06. 2010 16:00 »
Anjimehra,
I use ATF (Automatic transmission fluid) It has two advantages: 1) It is red which makes it very easy to diagnose if your primary chain case is leaking or weather a suspected oil leak is from some where else. 2) ATF is much thinner than any grade of engine oil and thus is less likely to cause the plates to stick while still providing  perfectly adequate chain lubrication. I do not have any experience of plunger clutches, but I would imagine that they are not that much different from S/A models. I assume you have the gearbox operating arm set correctly? Try ATF would be my advice, This is very common practice on all "Brit Bikes"

John

Offline anjimehra

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Re: Plunger clutch not releasing
« Reply #2 on: 28.06. 2010 17:14 »
Hi John
Thanks for the advise. I did suspect that the oil was too viscous, but I use 20/50 in my Enfield primary case & it works well. Will try ATF tomorrow & give you a feed back
Thanks once again
Anji

Offline a10gf

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Re: Plunger clutch not releasing
« Reply #3 on: 28.06. 2010 18:00 »
Anji, you've probably checked for wear, but if not, take a look at my old clutch page http://www.a7a10.net/BSA/clutch.htm for some ideas. And be sure all plain and friction plates are of the correct type & thickness, and in correct number and order. Are all the plates perfectly flat ?

The 6 spring plunger clutch is supposed to run 'close to' dry, as the dome cover and gasket will keep most oil out, IMO any type of oil will do. I would have cleaned everything in petrol, especially the friction plates, look for warped plates, and check closely for indents\wear in clutch basket or teeth of plates etc.

(All this assuming the push rod & everything at the gearbox works as it should)

e

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Offline anjimehra

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Re: Plunger clutch not releasing
« Reply #4 on: 29.06. 2010 13:42 »
Hi A10 GF
Thanks for the feed back. Yes, I have checked the steel plates for trueness. As I wasnt able to procure the standard dry clutch plates, I took the friction inserts off the old plates & glued on cork facing.Therefore, Iam not using the dome cover onthe clutch to allow the oil to access the clutch.In other words it is now operating as a wet clutch as in the later Flashes & Rockets.There is a certain amount of play in the slots in the clutch basket but I had no choice but to use the old plates. I have smoothed out the sides of the slots
Also, I have made a new clutch rod using EN 19 ( 11.5 ins ) hardened to 50RC at both ends.Atleast I assume its EN 19 as I havve to trust the vendor.
I took the cover off & operated the clutch.The end pressure plate moves out easily but the other plates stick together, resulting in creep.I have been able to fit on only 4 friction plates as there is no more room on the clutch hub ( center ). I presume this is because
the plates are not the right thickness.
I hope I havent confused the issue????
Take care
Anji

Offline a10gf

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Re: Plunger clutch not releasing
« Reply #5 on: 29.06. 2010 15:48 »
My only recommendation would be to get a set of new friction plates, and put the whole clutch back in original condition, including using the dome cover. I am of the impression that these plunger clutches works fine (mine has never given any problems) when all original and in good condition, and can give lots of trouble if not.

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Offline Stu55Flash

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Re: Plunger clutch not releasing
« Reply #6 on: 29.06. 2010 19:18 »
Hi Anj

I've had a similar problem with my Francis Barnett. The clutch plates were too thick with the result that the operating rod was not long enough to fully disengage the clutch plates. I used an electric drill and 5" abrasive pad to take 0.5mm off each side of each plate at a time. Don't know if this is the problem with yours but worth checking as the tolerances are fine and shared by all the clutch plate surfaces.

Stu
"Keep a distance from lady "L" drivers in cars. Some are not mechanically minded, are slow to acquire road sense, an are apt to panic..." The Pitman Book of the BSA Twins.
Golden Flash Plunger 1955, Francis Barnett Falcon 67 1954, Ferguson TEA Tractor 1951. Looking for another project!

Offline anjimehra

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Re: Plunger clutch not releasing
« Reply #7 on: 30.06. 2010 07:14 »
Hi Stu
Thanks for help. The rod is the correct length at 11.5 ins. Also any wear can be adjusted at the clutch operating arm on the g/box cover. The pressure plate is lifting sufficiently but the plates arent separating. Will be trying a thinner oil today & will post the results.
Anji

Offline anjimehra

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Re: Plunger clutch not releasing
« Reply #8 on: 01.07. 2010 12:32 »
SUCCESS
stripped down the clutch & thoroghly cleaned the plates etc.Made sure everything was sliding freely, topped with ATF & took off. The bike ran w/o any hassle from the clutch with easy gear & neutral selection & purred along smoothly. No creeping & clunking !!!!
Thanks a million guys for all your suggestions & help. Will post a few photos of the finished bike shortly.
You are all welcome to come to India & ride her
Anji

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Re: Plunger clutch not releasing
« Reply #9 on: 01.07. 2010 13:11 »
Anji,that is excellent news.

John

Offline anjimehra

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Re: Plunger clutch not releasing
« Reply #10 on: 02.07. 2010 12:42 »
Just an after thought. Will the ATF have any adverse effect on the seals?
Anji

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Re: Plunger clutch not releasing
« Reply #11 on: 02.07. 2010 12:58 »
Quote
Just an after thought. Will the ATF have any adverse effect on the seals?

None what so ever. There are plenty of oil seals in an automatic gearbox. I have been using ATF for 12 years with no adverse effects. Just relax and enjoy.

John

Offline Big Nick

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Re: Plunger clutch not releasing
« Reply #12 on: 02.07. 2010 21:56 »
surflex clutch plates and ATF
1932 500cc rudge
1936 500cc cotton pyton
1952 M20 with B31 motor
1952 Plunger A10
1954 New Hudson Autocycle
1962 A10
1982 BMW R100