The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: Greybeard on 26.05. 2018 09:06

Title: Considering dynamo belt conversion
Post by: Greybeard on 26.05. 2018 09:06
As I currently have my bikes engine stripped I'm pondering converting to a belt drive for the dynamo purely to reduce engine noise. What are the pro's and con's? I'm not bothered about converting to 12v electrics so would not be changing bulbs battery and regulator, (DVR2). I understand the belt drive changes the drive ratio to speed up the dynamo; does that wear the dynamo out quicker?
Title: Re: Considering dynamo belt conversion
Post by: Joolstacho on 26.05. 2018 09:12
Wow, is belt drive going to make any noticeable difference to 'engine noise'?
I doubt it.
Title: Re: Considering dynamo belt conversion
Post by: Triton Thrasher on 26.05. 2018 09:35
Wow, is belt drive going to make any noticeable difference to 'engine noise'?
I doubt it.

No and what’s wrong with engine noise anyway!
Title: Re: Considering dynamo belt conversion
Post by: Greybeard on 26.05. 2018 10:30
Just thinking as I'm doing stuff that should give me a quieter engine I could eliminate dynamo chain rattle.
Title: Re: Considering dynamo belt conversion
Post by: Joolstacho on 26.05. 2018 10:40
If it's rattling i's either:
WORN,
MALADJUSTED (like me), or
Not enough grease in there.
Man, just pack it, rotate it, and love it!
Title: Re: Considering dynamo belt conversion
Post by: RogerSB on 26.05. 2018 11:51
Without considering increasing dynamo output slightly for a 12v conversion some of the benefits I can think of are:-

It’s always clean in there.
Less maintenance as it doesn’t wear so much as a chain
If it breaks it’s unlikely to do a lot of damage – unlike a chain.
If you do want to convert in the future you’re half way there.
Some say it’s quieter but it’s a long time since I’ve heard the rattle of a dynamo chain to make a comparison.
Title: Re: Considering dynamo belt conversion
Post by: orabanda on 26.05. 2018 12:18
More importantly, the pulley on the dynamo is smaller; the dynamo runs faster therefore will start charging at lower engine speeds (commuting, around town).
The SRM kit spins the dynamo 10% faster.

The more recent alternative (can't remember name) speeds the dynamo up 20% and has a wider (15mm) belt.

Richard
Title: Re: Considering dynamo belt conversion
Post by: Billybream on 26.05. 2018 12:22
Agree with Roger, for me it's one less thing to worry about so you can devote more time to the things you have do whilst keeping our old girls alive and kicking.
Title: Re: Considering dynamo belt conversion
Post by: muskrat on 26.05. 2018 12:28
I've got belts on both of mine. Yes it is quieter. Set and forget.
I did have trouble in the start by having them too tight. Just right is very loose compared to the chain. The downside of that is if the screw boss has had chain damage it can eat the belt.
Cheers
Title: Re: Considering dynamo belt conversion
Post by: RogerSB on 26.05. 2018 12:37

The more recent alternative (can't remember name) speeds the dynamo up 20% and has a wider (15mm) belt.

Richard

It's by Dynamo Regulators Ltd., who also make the well respected, well used DVR2.  Mike Hutchings is a forum member and goes by Dynamo Regulators Mike. I think his version is the best. Mine is by SRM and was on my bike when I bought it but if I had to change it it would be replaced by the one made by Dynamo Regulators.

Edit: Crikey! I'm spending all my time on here lately.
Title: Re: Considering dynamo belt conversion
Post by: Greybeard on 26.05. 2018 12:54
I have the DVR2, which has been trouble free so I'm inclined to go for that set.
Title: Re: Considering dynamo belt conversion
Post by: morris on 26.05. 2018 15:59
Have Dynamo Reg on both plunger (6v) and SA (12v). No issues. Fit and forget.
Title: Re: Considering dynamo belt conversion
Post by: groily on 26.05. 2018 16:25
Sorry to hear about your woes GB  . . . but good luck, sounds as if you're all over it already.

On the belt thing, I have the same kit as Morris (and DVR2 running at 12). Haven't thought about it since fitting it a couple of years back. Which means I like it!
Probably is a bit quieter but it's a long time since I had a chain on there 'cos prior to the Dyn Reg Mike kit, I had the SRM one. (Which I did manage to kill in the end.)

Does it knacker the dynamo turning it faster? Don't think so - my dyn has lasted over 10 years without major surgery, and dunno how long it had been running before I got my hands on it. That's longer than any other dynamo on other bikes hereabouts, and I think is pretty darn good. (Mind you, I'm not doing Musky Revs!) It'll now fail, natch.

One point worth bearing in mind: You might find you have to ease off a little bit of alloy on the inner timing case 'compartment wall' to get pulley clearance: some castings are a bit fatter than others. I had to shave a bit off when fitting the first kit, to get the drive pulley on with adequate clearance and I believe some other people have had to do the same. But only talking a gnat's cock's worth and a dremel. (So, yes, an insect was seriously mutilated in the course of doing the mod, so I apologise to any outraged #metoo entomologists.)

But I guess the key Q is - Is it actually worth it for a 6v system, which will be quite fine as it was designed??
Title: Re: Considering dynamo belt conversion
Post by: morris on 26.05. 2018 16:37
One point worth bearing in mind: You might find you have to ease off a little bit of alloy on the inner timing case 'compartment wall' to get pulley clearance: some castings are a bit fatter than others. I had to shave a bit off when fitting the first kit, to get the drive pulley on with adequate clearance and I believe some other people have had to do the same. But only talking a gnat's cock's worth and a dremel. (So, yes, an insect was seriously mutilated in the course of doing the mod, so I apologise to any outraged #metoo entomologists.)
Right, forgot about that. The plunger needed a shave but the SA didn’t so there seems to be some variety in the cases.
Title: Re: Considering dynamo belt conversion
Post by: Greybeard on 26.05. 2018 16:55
Thanks, chaps; some great advice.
Title: Re: Considering dynamo belt conversion
Post by: OldSwede on 26.05. 2018 18:04
Hello again Greybeard. I installed a SRM belt and a new oil pump a couple of years ago. Works nice. Yes it revs 10% more than the standard so it will cause more wear. For me that is no problem. I use my A7 for meetings and rallies not for everyday driving.
Title: Re: Considering dynamo belt conversion
Post by: RoyC on 26.05. 2018 18:07
I have the DVR2, which has been trouble free so I'm inclined to go for that set.

I have also ordered one of these belt drives with a spare belt.

http://dynamoregulators.com/drive-belt-kit.php
Title: Re: Considering dynamo belt conversion
Post by: Greybeard on 26.05. 2018 18:10
Hello again Greybeard. I installed a SRM belt and a new oil pump a couple of years ago. Works nice. Yes it revs 10% more than the standard so it will cause more wear. For me that is no problem. I use my A7 for meetings and rallies not for everyday driving.
Very pretty! Shame to cover it all up!
Title: Re: Considering dynamo belt conversion
Post by: paulmbsa on 26.05. 2018 23:23
there shit, i hammer my dynamo always use the heated grips and often have lights on as well, V belts wear out quickly, thoothed belts not much better gone back to chain all good,
Title: Re: Considering dynamo belt conversion
Post by: Peter in Aus on 27.05. 2018 02:27
there shit, i hammer my dynamo always use the heated grips and often have lights on as well, V belts wear out quickly, thoothed belts not much better gone back to chain all good,
Me to, tried V belts B**** useless went back to chain, haven't tried tooth belts thou.
Peter
Title: Re: Considering dynamo belt conversion
Post by: muskrat on 27.05. 2018 03:40
G'day paulmbsa.
All the more reason to go up in the drive. Set up right the belt is far more superior.
Cheers
Title: Re: Considering dynamo belt conversion
Post by: RichardL on 27.05. 2018 04:04
My SRM belt went bad after not too long. Honestly, don't know if it was my fault or the belt's. In any case, bought two replacements from a belt supply house and no problems since. My spare lays in waiting, none the less.

Richard L.
Title: Re: Considering dynamo belt conversion
Post by: scotty on 27.05. 2018 05:47
I have an SRM dynamo drive toothed belt conversion

Seems ok to me but I never gave the chain drive a chance choosing to replace the chain on what was a basket case re build.

I don't put huge miles on my A10 but have not had issues with the toothed belt drive on the dynamo
Title: Re: Considering dynamo belt conversion
Post by: muskrat on 27.05. 2018 06:25
Since I adjusted my thinking on the belt tension I've had no problems. I had chewed up a few belts before this.
I was working on my plunger this morning and checked the belt. With very little pressure on the bottom run it was able to reach the screw boss (or where it used to be as I've ground it down flush, it was badly chain eaten) .
Cheers
Title: Re: Considering dynamo belt conversion
Post by: Black Sheep on 27.05. 2018 06:54
Haven't had any problems with the original chain setup (46 years and counting). The large sprocket is held by 6 shear rivets so that should a chain fail, the rivets shear (it's in the name) preventing further damage. This happened to me after an ill-advised 12 volt conversion caused the commutator segments to let go, seizing the dynamo and breaking the chain.
Title: Re: Considering dynamo belt conversion
Post by: muskrat on 27.05. 2018 09:28
I'd imagine if the same happened with a belt it would just eat a few teeth  *dunno*.
Cheers
Title: Re: Considering dynamo belt conversion
Post by: Dynamo Regulators Mike on 28.05. 2018 10:21
I just thought I would add my thoughts on a couple of the issues raised.

Firstly does the dynamo regulators belt drive kit with its 20% up-gearing wear the dynamo out more rapidly?
Well, the armature spins faster, but for a given electrical load the the mechanical input power to the drive is much the same (although the overall power conversion efficiency may well be improved). The field current in the dynamo will be lower, which also leads to lower armature heat dissipation. Friction loss in the belt may be a little greater as well as the windage (air drag in the dynamo but that is a small effect I believe). Our dynamos can well withstand the extra speeds encountered, the dynamo to crank speed being the same as in a magdyno. I say no need to worry about increased wear in dynamo.

So is the belt drive quieter than the chain?
Not necessarily, but more than likely. If the chain drive is not too worn and well adjusted and the chain has no tight spot all should run pretty quiet. But probably the great majority of all inner timing have grooves where the chain has rubbed. That is a noisy process! Many customers have been delighted with the enhanced quietness from the timing side in practice. Of course those with loud exhausts will have trouble perceiving any difference.

Many thanks for all those who have purchased our dynamo drive kit over the years, and more recently. Back to a normal working day tomorrow where the orders will be processed for same day posting. Hope you avoid the thunder storms in UK if out and about later.

Title: Re: Considering dynamo belt conversion
Post by: RoyC on 30.05. 2018 18:19
My DRL belt drive arrived today, when fitting the small pulley, washer and supplied nut, the nut sticks out past the pulley  7/16", is this correct ?
Title: Re: Considering dynamo belt conversion
Post by: morris on 30.05. 2018 18:49
Do the pulleys line up?
Title: Re: Considering dynamo belt conversion
Post by: RoyC on 30.05. 2018 18:59
Do the pulleys line up?
I have only fitted it onto the new dynamo at the moment.
Dynamo not fitted to the bike yet.
Title: Re: Considering dynamo belt conversion
Post by: Greybeard on 30.05. 2018 19:26
My DRL belt drive arrived today, when fitting the small pulley, washer and supplied nut, the nut sticks out past the pulley  7/16", is this correct ?
I'm sure Mike, the proprietor will be able to answer you soon. How about a picture?
Title: Re: Considering dynamo belt conversion
Post by: RogerSB on 30.05. 2018 19:29
My DRL belt drive arrived today, when fitting the small pulley, washer and supplied nut, the nut sticks out past the pulley  7/16", is this correct ?

Roy, see reply no. 13 by Mike Hutchings, which shows a good picture of it and it looks like it does.
https://www.a7a10.net/forum/index.php?topic=3748.0

Also in the .pdf instructions after the 'Description of Features' on his 'Dynamo Belt Drive Kit' webpage it show the same picture but smaller.
Title: Re: Considering dynamo belt conversion
Post by: RoyC on 30.05. 2018 19:37
My DRL belt drive arrived today, when fitting the small pulley, washer and supplied nut, the nut sticks out past the pulley  7/16", is this correct ?
How about a picture?

I notice, on that picture that the boss has been half removed. Does this have to be done also ?


Title: Re: Considering dynamo belt conversion
Post by: RogerSB on 30.05. 2018 20:00
Remembered I had a photo of my SRM version taken from above so easier to see without the pespective foreshortening it - and the nut on the SRM version sticks out quite a way as you can see. Must be a reason for it but  *dunno*. Maybe Mike Hutchings can tell us.
Title: Re: Considering dynamo belt conversion
Post by: RogerSB on 30.05. 2018 20:06
I notice, on that picture that the boss has been half removed. Does this have to be done also ?

No Roy, it was done by a slack chain whipping up and down before the belt was fitted
Title: Re: Considering dynamo belt conversion
Post by: RoyC on 30.05. 2018 21:13
Remembered I had a photo of my SRM version taken from above so easier to see without the pespective foreshortening it - and the nut on the SRM version sticks out quite a way as you can see. Must be a reason for it but  *dunno*. Maybe Mike Hutchings can tell us.
That does answer my question Roger. Thanks.
Title: Re: Considering dynamo belt conversion
Post by: morris on 30.05. 2018 22:14
If I remember well, the nut sticks out indeed. The hole in the small pulley is quite deep and to small for a socket so with the nut tight you wouldn't have any hexagon left to get a spanner or socket on.
Title: Re: Considering dynamo belt conversion
Post by: Dynamo Regulators Mike on 31.05. 2018 08:39
The 7/16" from end of dynamo nut to pulley face is quite normal. Still a long way from touching on the outer timing cover, and does not cause any real problem. The spring washer we supply is a thick one at about 1/10", and could be thinner. The base of nut to hex could be reduced by a tenth or so. There is a certain tolerance on the nut of course, and that distance has not been well controlled by the machinist. We might change the drawing to tighten things up. But little to gain from doing so, as this is pretty much a cosmetic issue I feel.
Title: Re: Considering dynamo belt conversion
Post by: Greybeard on 31.05. 2018 20:22
The kit plus a spare belt arrived today. Lovely grub!  *smile*
Title: Re: Considering dynamo belt conversion
Post by: bsa-bill on 31.05. 2018 20:42
Back in the day as they say, I used to get through dynamo chains on piece, young and not to mechanically skilled of course so maybe my fault but I'm sold on belts, toothed
Title: Re: Considering dynamo belt conversion
Post by: RoyC on 01.06. 2018 07:31
I have read that some people are still packing with grease to keep the belt cool,
Is this really necessary ?
Title: Re: Considering dynamo belt conversion
Post by: muskrat on 01.06. 2018 07:56
Not since I run it loose.
Cheers
Title: Re: Considering dynamo belt conversion
Post by: RoyC on 02.06. 2018 15:08
What holds the drive sprocket on (the one with rivets in) ?
I have removed the nut and washer and tried to pull it off with a puller, but it won't budge.  *help*
Title: Re: Considering dynamo belt conversion
Post by: morris on 02.06. 2018 15:15
What holds the drive sprocket on (the one with rivets in) ?
I have removed the nut and washer and tried to pull it off with a puller, but it won't budge.  *help*
It's on a taper but can be a real bugger to get off  *ex*
I remember when I removed mine I completely destroyed it.
Title: Re: Considering dynamo belt conversion
Post by: berger on 02.06. 2018 15:25
treat it like you would a car ball joint taper, give it some pink Floyd a short sharp shock with a brass or copper drift
Title: Re: Considering dynamo belt conversion
Post by: duTch on 02.06. 2018 16:35

 Last time I did it, I packed under the sprocket diametrically with flats & wedges, and gave the loosened nut on the spindle a whack- may need a bit of heat (after packing & wedging), or even a tap on one side of the sprocket to whack it cock-eyed...
Title: Re: Considering dynamo belt conversion
Post by: RoyC on 02.06. 2018 18:04

 Last time I did it, I packed under the sprocket diametrically with flats & wedges, and gave the loosened nut on the spindle a whack- may need a bit of heat (after packing & wedging), or even a tap on one side of the sprocket to whack it cock-eyed...
Thanks again lads.
Got it off without any damage to it.
I held the pressure on with a 2 arm puller and at the same time tapped it a few times with a hammer and it popped off.  *good3*
Title: Re: Considering dynamo belt conversion
Post by: Peter in Aus on 03.06. 2018 01:58
Be careful hitting the shaft as it is pressed on to the gear (67-335) and its easy to knock the shaft through the gear a bit causes all sorts of problems . Been there done that  *warn*  *problem*
I have drilled an taped two holes in the sprocket to attach a puller so as not to have this problem.
Peter
Title: Re: Considering dynamo belt conversion
Post by: duTch on 03.06. 2018 04:07

 
Quote
Be careful hitting the shaft as it is pressed on to the gear (67-335) and its easy to knock the shaft through the gear a bit causes all sorts of problems . Been there done that  *warn*  *problem*

 I think that's the reasoning behind my suggestion, but forgot that bit thanks Pete
  Good idea about the puller holes  *wink2*
Title: Re: Considering dynamo belt conversion
Post by: RoyC on 03.06. 2018 08:09
Be careful hitting the shaft as it is pressed on to the gear (67-335) and its easy to knock the shaft through the gear a bit causes all sorts of problems . Been there done that  *warn*  *problem*
I have drilled an taped two holes in the sprocket to attach a puller so as not to have this problem.
Peter
I tapped on the side of the pulley, not the shaft itself.
Thanks for that anyway, I didn't know about that.
Title: Re: Considering dynamo belt conversion
Post by: RoyC on 03.06. 2018 12:33
What is the standard size sprocket on the E3L dynamo ?
I have two E3L dynamos, one has 13 teeth and the other has 11 teeth.  *conf2*
Title: Re: Considering dynamo belt conversion
Post by: duTch on 03.06. 2018 13:59

 If you plan to use one, would be best to use the 11T anyway- better ratio (I think that's what should be, but why bother with the 13T)
Title: Re: Considering dynamo belt conversion
Post by: RogerSB on 03.06. 2018 15:01
What is the standard size sprocket on the E3L dynamo ?
I have two E3L dynamos, one has 13 teeth and the other has 11 teeth.  *conf2*

Hi Roy, same for A Group 1958-59 models and 1960-62 models. See no 44 in 1958-59 diagram.
Title: Re: Considering dynamo belt conversion
Post by: RoyC on 03.06. 2018 18:47
What is the standard size sprocket on the E3L dynamo ?
I have two E3L dynamos, one has 13 teeth and the other has 11 teeth.  *conf2*

Hi Roy, same for A Group 1958-59 models and 1960-62 models. See no 44 in 1958-59 diagram.
Yes, 11 T is the correct one.
Title: Re: Considering dynamo belt conversion
Post by: RoyC on 03.06. 2018 18:52

 If you plan to use one, would be best to use the 11T anyway- better ratio (I think that's what should be, but why bother with the 13T)

I am not reusing them, I am in the process of fitting a DRL belt drive.
Title: Re: Considering dynamo belt conversion
Post by: chaterlea25 on 03.06. 2018 19:10
Hi Roy,
The 13 tooth sprocket is from the C10/11 single models as far as I know

John
Title: Re: Considering dynamo belt conversion
Post by: trevinoz on 03.06. 2018 22:53
The 13 tooth was used on the E3H short generator on the A7 as well as the C10/11.
Title: Re: Considering dynamo belt conversion
Post by: RoyC on 04.06. 2018 18:24
All fitted.

Title: Re: Considering dynamo belt conversion
Post by: RogerSB on 04.06. 2018 20:57
Looks good *smile*.
Title: Re: Considering dynamo belt conversion
Post by: Greybeard on 04.06. 2018 21:21
Mine should be on soon
Title: Re: Considering dynamo belt conversion
Post by: RoyC on 04.06. 2018 21:44
Mine should be on soon
I fitted new sealed bearings in the new dynamo, tested to see if running in correct direction and flashed it for +ve earth.
Title: Re: Considering dynamo belt conversion
Post by: Billybream on 05.06. 2018 10:20
Matches mine, shame it's covered up, fit and forget