Author Topic: a65 triplex chain  (Read 206 times)

Offline edboy

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a65 triplex chain
« on: 13.05. 2019 19:17 »
hello. i have a a65 triplex chain and clutch and sprockets. i wondered if any body tried this settup on an a10 as the drive sprocket fits.
can the chain be bought in different lengths?

Offline RDfella

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Re: a65 triplex chain
« Reply #1 on: 13.05. 2019 20:05 »
Does the chainwheel fit? Never been a fan of triplex chains on bikes - flexibility of things like gearbox mainshaft mean rarely is the load taken by all three rows. Usually two or just one if flex is bad. As with all commercial chain, you can get whatever length you want.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online trevinoz

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Re: a65 triplex chain
« Reply #2 on: 13.05. 2019 22:26 »
It fits, Ed.
A mate had this on his A10 for a while.

Offline edboy

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Re: a65 triplex chain
« Reply #3 on: 14.05. 2019 19:31 »
ok thanks for info.
i m tempted to machine the drive side to also fit a rotor like the a65 .

Online BSA_54A10

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Re: a65 triplex chain
« Reply #4 on: 15.05. 2019 10:48 »
The gearbox mainshaft has the same taper on almost every BSA from 1910 through to 1972 so it is possible to fit almost any clutch to an A10, including an A 65 one.
However you may need to bore the hole in the clutch hub to get it spaced correctly on the main shaft.
I am fairly sure the engine shaft spline is the same as unit A & B engines.So again it is just a matter of spacers
Bike Beesa
Trevor

Offline RDfella

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Re: a65 triplex chain
« Reply #5 on: 15.05. 2019 15:59 »
I thought the semi-unit one - not that it applies in this case - was splined?
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online Swarfcut

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Re: a65 triplex chain
« Reply #6 on: 15.05. 2019 17:29 »
Quite correct, RD.
   The plunger box (semi- unit) has a splined input shaft. The weakness with this design is the pitifully small area to locate the rear thrust washer supporting split ring.  The  taper type used for all the others is fine, as long as the centre nut is well tightened. Damaged tapers, sheared keys,  and damaged keyways are all to common, because of a failure to tighten the centre nut enough. If tightened correctly the taper type clutch centre adaptor  can require considerable violence etc to pull off the input shaft.

 This is where the plunger clutch is better, the straight splined clutch centre slides off far more easily, and the splines give a positive drive, even if the centre nut is not super tight.  There is not much material supporting the thrust washer split ring, its a bit like a wing and a prayer as you tighten the nut.

 Swarfy.

Online chaterlea25

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Re: a65 triplex chain
« Reply #7 on: 15.05. 2019 22:13 »
Hi All,
Swarfy, I have to disagree about the tapers? the unit A50/65 are different to the older BSA stuff,
A65 and Triumph tapers are the same
To fit the A65 clutch on an A10 a 4 spring shaft adaptor is needed

John
1961 Super Rocket
1963 RGS (ongoing)

Online Swarfcut

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Re: a65 triplex chain
« Reply #8 on: 16.05. 2019 06:53 »
    CJ... You are probably correct. I did not suggest the angle of taper was the same, for all models and years from way back (someone else did) but experience here would indicate that the later triplex A65 Clutch can be mated successfully to a standard A10 mainshaft.

 My comments on the Plunger Clutch were to show the inherent weakness of an otherwise excellent design, which is a possible reason why BSA went back to the taper shaft design for the S/A models.

 

 Swarfy.

Offline ironhead

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Re: a65 triplex chain
« Reply #9 on: 16.05. 2019 08:00 »
G'day all
The spline & 2 half clips is a good set up. Commando's use this exact set up with no problems ( twice the horsepower & heavier clutch) The nut needs to be tightened firmly, not so tight the circlips get deformed.
Id put a Commando clutch in the plunger tomorrow if I could shrink it to fit inside the primary case. *work*
SA

Online Swarfcut

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Re: a65 triplex chain
« Reply #10 on: 16.05. 2019 08:17 »
 Ironhead... Yes, a clever design. My niggle is that the depth of engagement for the split ring on the shaft is very small, like hanging on a mountain ledge with just your fingertips. BSA could have been a bit more generous in machining a deeper locating groove, but then we start to weaken the shaft at a critical point.

 Swarfy.