The BSA A7-A10 Forum

Technical (topic titles must be descriptive) => A7 & A10 Engine => Topic started by: sprint on 26.05. 2014 19:32

Title: Fitting Dynamo Regulators Dynamo belt kit
Post by: sprint on 26.05. 2014 19:32
I'm in the process of fitting the dynamo belt kit and would appreciate some advice from any of you who have already fitted one.

The recommended tension is when you can twist the middle of the lower run by about 45 deg each way. There is fair amount of rotation of the dynamo over which that is possible so how do you gauge the correct tension?

There is a raised boss between the top and bottom runs, see photo in second page of fitting instruction http://www.dynamoregulators.com/documents/belt_drive_data.pdf, should you able to easily press the lower run to touch this boss or not?

Is is wise to use some loctite on the dynamo nut as it is simply not possible to apply force to tighten the nut without it slipping?
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: muskrat on 26.05. 2014 21:15
G'day sprint.
The belt shouldn't be able to touch the boss easily but can with some effort. That boss has more than likely been hit by the chain and left gouges on it. This destroyed two belts on mine. Tensioned to the rec setting the belt will hit it so tension a bit tighter or remove the boss as I did on my cafe. (can't find the picture)
I don't use loctite on that nut. If the taper is good a gentle tap should lock it enough to tighten the nut.
Cheers
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: morris on 26.05. 2014 22:22
Hi Sprint,
I go with Musky.
These belts are steel reinforced so won't snap that easily and can have a fair bit of tension.
I didn't use the spring washers that came with the kit though as I found them a bit heavy.
I have a batch of soft and thin spring washers I use for that kind of purpose.
Normally you shouldn't have trouble tightening the nut with the belt correctly tensioned. You could overtighten the belt a bit, tighten the nut and then back off again
I have done nearly 2000 miles since the conversion and when I opened the timing case recently, the belt was still as new.
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: sprint on 27.05. 2014 15:25
Thanks for the replies and advice.

Andy
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: denis on 27.05. 2014 15:30
Good day all,

if i may squeeze in a little trouble/question I have with that kit; The bigger wheel is in the way of the cover on mine, it touches on the little wall between the wheel and the oil pump, on the cover side.  What am i doing wrong? 

Thanks , Denis 
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: bsa-bill on 27.05. 2014 17:46
My first one did the same Dennis, I ground a little of the wall away and checked the outer cover, it was okay.
I have a few inner and outer covers and they do differ a little from one to another, probably just different casts
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: sprint on 27.05. 2014 19:27
I have had no problem on mine, so it must be as Bill suggests that there is some variance in the castings.

Is it the inner or outer case that you are having a problem with?

Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: morris on 27.05. 2014 20:47
Hi denis,

I don't now how I missed the fact that there was another fellow countryman around but somehow I did... *red*
Only a couple more and we beat the Brits and Aussies *smile*

I had the same issue with the plunger. The outer cover doesn't fit the inner very well also, which makes me think it has been replaced at some stage.
Like Bill, I got the invaluable dremel out and ground a little bit away on the inside of the cover until it cleared.
If its the outer cover, smear a bit of grease on the edge of the bigger pulley. Then put the cover on. The trace of grease the pulley leaves on the edge tells you how far you have to go
The SA didn't have this problem though, and also the outer cover on the SA fits the inner noticeably better
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: muskrat on 27.05. 2014 20:53
G'day sprint. Looks good but what is this?
Cheers
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: morris on 27.05. 2014 20:58
Well spotted Musky!
Now I'm curious to!
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: bsa-bill on 27.05. 2014 21:21
tab washer (on vacation I'd say)
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: morris on 27.05. 2014 22:56
tab washer (on vacation I'd say)
Right! tab washers also have the right to relax sometimes says the tab washer union.... *smile*
Although from experience they usually take a day off on a most inconvenient moment...
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: sprint on 28.05. 2014 08:42
G'day sprint. Looks good but what is this?

Well spotted.

I too was concerned when I first saw the photo but it is just an effect of the flash.

If you can blow the photo up or look very carefully it is in fact the teeth of the crank gear with the reflection of the orange oil on the surface behind.
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: duTch on 28.05. 2014 08:43
 I also had the same issue fairly much same spot, had to do some sculpting, but also as the surfaces mis-matched, I had to build up a bit on the under(pump)side.....and I think the outer and sculpt that too
  There's piccies in another post here somewhere.....
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: denis on 28.05. 2014 09:13
Thanks guys and long live this forum  *smile*

I did try my spare outer cover with no luck either thinking about the difference in castings.   They are actually very different! I 'll do the carving when time allows.
Morris; we might one day outnumber the Aussie's and the Brits on this forum: I reluctantly sold my non running swing arm to a friend about a month ago.  He will very soon need the knowledge from all you A10 Wizzards aswell! 
Thanks all,

Denis
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: muskrat on 28.05. 2014 11:03
DOH   *bash*
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: Peter in Aus on 01.06. 2014 05:25
I to have just fitted a drive belt kit to my A7 longstroke had no trouble with clearance but was not happy about tightening the alon screw holding the pulley to the Alton generator.
the way I over come it was to slide the generator back far enough to be able to get a pair of multi grips on the boss of the pulley between the inner housing and the generator prior to putting the belt on.
I tensioned the belt by turning the generator as much as I could by hand and locked it up at that.
Cheers
Peter 
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: bsa-bill on 01.06. 2014 08:54
Quote
I tensioned the belt by turning the generator as much as I could by hand and locked it up at that.Cheers

don't know about plungers but on the S/A the dynamo will turn away from  the engine as it's tightened down thereby making the belt to tight so allow for this
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: muskrat on 01.06. 2014 09:14
Yes the same Bill. Beware Peter, the belt will tighten as you do the clamp nut up.
Cheers
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: duTch on 01.06. 2014 09:30

 Did I read or imagine that someone suggested giving the pulley/ies a light tap with a sleeved drift onto the taper to hold it in place...?
  Either way try that...?
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: muskrat on 01.06. 2014 11:01
Yes duTch but that was to tighten the dynamo shaft nut.
When adjusting the belt/chain do so it's a little loose. That way it will tighten as the clamp nut is tightened. After a couple of goes you know how much slack it needs.
You knew and do this but it's just one of those automatic things when done often enough, like rockerbox's. *pull hair out*
Cheers
Title: Re: Fitting Dynamo Regulators Dynamo belt kit
Post by: duTch on 01.06. 2014 12:04

 Aaaaah yeah *shh* went back and re-read a few and got mixed up- making Richard look good....!