Author Topic: A10 Sunbeam  (Read 698 times)

Offline cyclobutch

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A10 Sunbeam
« on: 06.07. 2015 16:25 »
I was at the SoF (Sunbeam) rally in Derbyshire at the weekend. Mostly S7 and S8 motorcycles in various states of use as you would expect. One of them though had been through a conversion to A10 power. I think I might have seen pics of this one before but never in the flesh. Effectively the engine was turned sideways so that the crank output ran into the Sunbeam bell housing before driving through what appeared to all be std Sunbeam transmission to the rear wheel. Given the reputation that has for a certain level of frailty you can only wonder how it copes with the A10 output. The motor was all iron and with thin flange barrels so is presumably running in fairly soft tune – and I did have to wonder how the cooling worked out for the now rear cylinder. Timing chest faced forward of course, which did look decidedly odd. But all in, quite a feat of engineering of course.

I took a whole bunch of pics and I’ll try and work out how to post some.   
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Online chaterlea25

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Re: A10 Sunbeam
« Reply #1 on: 06.07. 2015 17:13 »
Hi cyclo,
The Sunbeam transmission must be stronger than the credit its given ??
Theres a very decrepit (rat) Sunbeam running in Ireland with a 1200 (?) VW engine *conf2*
The conversion had  been done a long time ago, and I suppose was just abandoned eventually
It was found years later and returned to the road (as is)

Cheers
John
1961 Super Rocket
1963 RGS (ongoing)

Offline cyclobutch

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Re: A10 Sunbeam
« Reply #2 on: 06.07. 2015 21:24 »
Trying ... to post ... pics ....
Various, including ...
'58 Iron Head Flash Bitza


Offline cyclobutch

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Re: A10 Sunbeam
« Reply #3 on: 06.07. 2015 21:27 »
Hmmmm, had to down size quite a chunk from what was suggested. Hopefully here are three more:
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'58 Iron Head Flash Bitza


Online chaterlea25

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Re: A10 Sunbeam
« Reply #4 on: 06.07. 2015 21:55 »
Hi All,
Hmmmm *ex* *ex*
Something very odd about the way the dynamo/garden tractor alternator is sitting (Not??)  *eek* *eek*

John
1961 Super Rocket
1963 RGS (ongoing)

Online Greybeard

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Re: A10 Sunbeam
« Reply #5 on: 06.07. 2015 22:13 »
The engineering looks very good to me.

Online chaterlea25

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Re: A10 Sunbeam
« Reply #6 on: 06.07. 2015 23:38 »
Hi
Greybeard,
look and you will see a tapering gap between the dynamo housing and the crankcase cradle *conf2*
To align the drive the dynamo body needs to sit into the cradle properly

Cheers
John
1961 Super Rocket
1963 RGS (ongoing)

Online duTch

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Re: A10 Sunbeam
« Reply #7 on: 07.07. 2015 03:24 »

 I'll stick my neck out and suggest that there is a short bearing housing where the genny usually sits, with some kind of offset interim 'flex-drive' between there and an alternator against the bell housing, the interim drive having a tin cover over it.
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Online RichardL

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Re: A10 Sunbeam
« Reply #8 on: 07.07. 2015 04:40 »
Well, John certainly has the eye for "garden tractor alternators". I never would have known that, then, searching Google images for that exact phrase brings up that exact piece. Then, I was going to question Dutch's flex drive, but there needs to be some way to adjust chain/belt tension while the alternator stays fixed in place, so flex drive makes sense. Dutch's bearing housing appears to be used as the former for the tin cover, held in shape by the three allen screws. I think the tin cover is mostly for aesthetics, so the fact that it doesn't sit in or align with the cradle wouldn't matter much. What I really don't understand (but will become obvious to me as soon as I'm told) is: why not just use an original dynamo?

All of the above aside, when I heard about this bike, I was expecting some bodgy thing but, as Greybeard said, the engineering looks very good. Really, to me it's pretty amazing.

Richard L.
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Re: A10 Sunbeam
« Reply #9 on: 07.07. 2015 05:38 »

 Actually, when I say flex drive, I really meant flex coupling(s) one each end like a rudimentary universal joint like on a steering shaft or similar drive shaft... did that in a hurry as I still am (again)
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Online Klaus

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Re: A10 Sunbeam
« Reply #10 on: 07.07. 2015 07:34 »
my opinion is the alternator is an alton right in place, driven with a belt or chain. the dyno is parallel with the barrel, so l gues it is an optical illusion. altons are much shorter as genny dynos,so there is enought space for an electrikstart at the oposite.
the bike is clever build, and it make no sense to use a flexi drive.

sorry for my write smal, l breake my collar bone by racing with the a10 , slipping the frontweel, last sunday *roll*

only the left footrest is a twisted and a soft tuch on the fairing.

klaus


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Online Greybeard

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Re: A10 Sunbeam
« Reply #11 on: 07.07. 2015 08:39 »
...I breake my collar bone by racing with the a10 , slipping the frontweel, last sunday...

 *sad2*

Offline tombeau

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Re: A10 Sunbeam
« Reply #12 on: 07.07. 2015 09:16 »
Impressive.
Wouldn't want to have to remove the timing side cover though.

Online muskrat

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Re: A10 Sunbeam
« Reply #13 on: 07.07. 2015 11:37 »
Wonder what the extra plate between the timing covers is for?
Cheers
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Offline Topdad

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Re: A10 Sunbeam
« Reply #14 on: 07.07. 2015 12:17 »
A bit of additional clearance for the genie drive ??
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