Author Topic: Dynamo Belt Drive  (Read 6922 times)

Offline kiwipom

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Dynamo Belt Drive
« on: 03.02. 2011 03:48 »
hi guys,recieved belt drive for dynamo today, i have temp fitted it to make sure all is well,seems to be. It is a twin belt and pulley kit from Sean Hacker Electrical i have a couple of pics for anyone who is interested. I decided to get one when i read that if that chain broke it would wreck the engine. It will be quieter and less dangerous if belts break that was my thinking, has anyone else done the conversion?
cheers, Bob.
A10.G.Flash(cafe racer)Honda 250 vtr. Yamaha Virago XV920.

War! what is it good for?Absolutely nothing, Edwin Star.
NewZealand

Offline brackenfel

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Re: Dynamo Belt Drive
« Reply #1 on: 03.02. 2011 07:19 »
Hi Bob,
That looks neat, should keep the dynamo grease-free as well! Sean is based not far from me, I'll have a look at the Shepton Jumble, he's usually there..
Cheers,
Adrian
1961 A10 650 Golden Flash - Blue
1954 BSA B33
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Offline MG

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Re: Dynamo Belt Drive
« Reply #2 on: 03.02. 2011 09:08 »
Hello Bob!

I'm using dynamo belt drives on both my A's, it's the SRM kit though (looks very similar to yours). Works a treat, very quiet and, as you said, safe in operation.



Cheers, Markus

P.S. Someone nicked your breather!  *smile*

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Offline Dynamo Regulators Mike

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Re: Dynamo Belt Drive
« Reply #3 on: 03.02. 2011 09:20 »
Hi Kiwipom
I have had a similar belt drive on my A10 for the past 3 years. Mine was from Sean Hawker ;)
Quieter and cleaner it is, and the up-gearing is of real benefit to me running 12V, with a DVR2  *smile*
I found it was essential to have a small seal fitted behind the large pulley to prevent oil seepage which otherwise caused belt slippage  *sad2*
I have gone through a few belts to date, but I do run with a Boyer ignition and a 45W headlight (LED's elsewhere). The belt does needs to be tight and needs a re-tension now and then. I reckon on a few thousand miles per belt, and always carry a spare  *idea*
In retrospect a toothed timing belt like the SRM may have been a better choice for me (the perceived risk of shock load damage minimal?), or I reckon that a poly V belt would be ideal for the application  ????
Cheers
Mike
Mike Hutchings
A10, B50, T800; 1,2,3 (& DVR2)
Director, DRL www.dynamoregulators.com

Offline kiwipom

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Re: Dynamo Belt Drive
« Reply #4 on: 03.02. 2011 09:43 »
hi guys, yes you guys who are running this belt drive obviously know the benifits, mine is just for show at the moment i am still building the engine that is why you cannot see the breather M.G. what you see is only temperary put together. Sean tells me that this is the latest design, Two Belts, so don`t know why he chose to change things but it looks good to me, Mike it also comes with the small seal you mentioned.
 I am waiting for some parts from S.R.M. to see if i can get the 4 spring clutch sorted then i should be able to finish the engine,cheers
Bob
A10.G.Flash(cafe racer)Honda 250 vtr. Yamaha Virago XV920.

War! what is it good for?Absolutely nothing, Edwin Star.
NewZealand

Offline MG

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Re: Dynamo Belt Drive
« Reply #5 on: 03.02. 2011 10:26 »
oh, it's twin V-belts, so actually quite different to the SRM kit.
1955 A7 Shooting Star
1956 A10 Golden Flash
1961 Matchless G12 CSR

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Online bsa-bill

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Re: Dynamo Belt Drive
« Reply #6 on: 03.02. 2011 10:37 »
I run the SRM toothed belt drive and it does not slip in oil - (if changing idler pulley bushes get them the correct way around   *doh* )

Comes with both a cork and felt seal these days - choose whichever fits best

Twin belt is new though as far as I know, should be better but depends on both belts being the same tension, don't know how much leeway there would be before one belt is more or less redundant, if you follow my drift, could be I'm nitpicking. 
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 Dynamo Regulators Mike

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Re: Dynamo Belt Drive
« Reply #7 on: 03.02. 2011 10:59 »
Bill, surely the only way the toothed belt would slip in oil would be if the teeth strip because the belt is not oil resistant  *conf*
I had a lip seal fitted behind mine. The cork was inadequate. Can't see felt being much better but the SRM belt can take a smear of oil anyway.
I wondered about equal belt tension as well but I expect the one doing more work will soon stretch until the other comes into play. Presumably the twin version is a reaction to people who have had problems with belt life. Difficult to tell if belts are both 6 x 400 as single version was. To get the gearing up the small sprocket is a bit small for this size.
That's where poly V belt would score. Effectively 4 or 5 small V belts side by side with lots of grip area, and being thin can employ a smaller pulley without premature wear.
Kiwipom, if you don't mind me asking has the price risen from £60 on website, or is Sean accepting a lower margin on the twin kit?
Mike Hutchings
A10, B50, T800; 1,2,3 (& DVR2)
Director, DRL www.dynamoregulators.com

Offline muskrat

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Re: Dynamo Belt Drive
« Reply #8 on: 03.02. 2011 12:43 »
G'day Bob,
              Me two, on both A7 & A10. One is a SRM the other is from Lytedrive down here in Oz. Both are toothed belts but the local one is only 5% up-geared compared to the SRM at 10%. I've had one belt go toothless, a little loose and caught up on the lug. Ground the lug down and now use a counter sunk screw. I also taped two holes in the large pulley like yours. Both the cork and felt seals only lasted a few hundred miles, will have to go a lipped seal.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Online bsa-bill

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Re: Dynamo Belt Drive
« Reply #9 on: 03.02. 2011 14:59 »
Ah now manormike I maybe didn't express my self correctly there, I was trying to make the point that the SRM belt wont slip in oil, by fitting the idler bushes A*** first I managed over a period of some time to fill the dynamo drive chamber to the point that the oil eventually came out past the Dynamo cork, in all that time the Dynamo charged.

Poly Vee should work ok also, although the Dynamo pulley is very small diameter, still Alternators on cars seem to drive OK with a Poly Vee  and often there's no pulley at all just the shaft
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 kiwipom

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Re: Dynamo Belt Drive
« Reply #10 on: 03.02. 2011 22:23 »
hi guys, looks like i refered to sean hawker as sean hacker, my opologies. Yes it is a twin system both belts are 6x400 made in germany obviously good quality there. By your posts i will have to look at replacing the cork gasket with something else. The twin kit cost was 68 quid plus postage, we do not pay v.a.t as we are outside the e.u but 12.50 track/trace takes care of any saving, however i think it is money well spent, cheers
Bob
A10.G.Flash(cafe racer)Honda 250 vtr. Yamaha Virago XV920.

War! what is it good for?Absolutely nothing, Edwin Star.
NewZealand

Offline bikerbob

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Re: Dynamo Belt Drive
« Reply #11 on: 04.02. 2011 12:25 »
HI There
I did quite a number years ago fit a belt drive to my A10 but I had to keep adjusting it too often every few hundred miles it was always slipping, this was before SRM made theirs available. I now think the problem was no oil seal behind the large pulley. If you check an original parts list you will see that an oil seal is listed part no.67-708 but when I restored my A10 in the mid ninties nobody stocked it, I did contact the BSA ownersclub tech consultant about this and he told me that the oil seal was discontinued quite early on as it was deemed unneccessary as the small amount of oil that could come through would just drain down into the sump. He did however say that you should fit a shim behind the pulley to take up any endfloat. I may go back to a belt drive at sometime but would buy one with a toothed drive like the one sold by SRM which would stop any slipping. BOB 

Offline muskrat

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Re: Dynamo Belt Drive
« Reply #12 on: 04.02. 2011 12:51 »
G'day Bob,
              the oil would only drain back to the sump once the level reached the bush. I have had no seal in the cafe for about 500 miles and yesterday took the cover off to find only a teaspoon or oil in there.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Offline Dynamo Regulators Mike

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Re: Dynamo Belt Drive
« Reply #13 on: 10.02. 2011 10:07 »
There is now, or will be very soon another and better dynamo belt drive option. Quiet, strong and non-slip.

The picture shows a timing belt type drive which uses a wide 15 mm belt for long life. The speed ratio is 20% up on the standard A10 ratio so electrical loads are balanced at modest road speeds even at 12V.

Dynamo Regulators Ltd www.dynamoregulators.com home of the DVR2 regulator will have them available in a week or two.
Mike Hutchings
A10, B50, T800; 1,2,3 (& DVR2)
Director, DRL www.dynamoregulators.com

Offline muskrat

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Re: Dynamo Belt Drive
« Reply #14 on: 10.02. 2011 11:42 »
G'day Mike,
               looks good. May I suggest two tapped holes in the drive pulley to aid removal.
I see the screw boss has been eaten by the old chain. Mine was the same and it ate all the teeth off the belt (I know too loose). I ground mine down and use a counter sunk screw. Now if it goes slack no damage done.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7