Author Topic: SRM dynamo belt drive  (Read 2961 times)

Online orabanda

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SRM dynamo belt drive
« on: 02.01. 2013 02:11 »
Happy new year everyone!
After 2,000 miles, the belt has failed!

It is still in one piece (all of the steel re-inforcement wires intact), but some inner teeth and external areas of the material (nylon?) have come away. this resulted in the belt coming off the dynamo pully; therefore - no charge!

Has anyone else had this problem?

I have fitted this system to 8 bikes, but this is the first time there has been a problem.

Richard

Offline Brian

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Re: SRM dynamo belt drive
« Reply #1 on: 02.01. 2013 02:56 »
What a jolly old nuisance old chap.

I fitted this type to mine

http://dynamoregulators.com/drive-belt-kit.php

The one in my 61' A10 has been in for about 10,000 miles and still looks as good as the day I fitted it.

Hopefully you just had a dud belt or something simple.

Online muskrat

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Re: SRM dynamo belt drive
« Reply #2 on: 02.01. 2013 13:00 »
 G'day Richard. Yep had a few go west in no time. A few like yours and a couple snapped. The '51 is the worst offender, the cafe has only eaten one. Can't seem to get the belts here (AT5 420/10) so have a spare in the bike kit and order two more for the shelf.
 I think I found the problem with the '51. The idler shaft isn't real tight in the pinion and floats outwards causing pulley misalignment.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online chaterlea25

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Re: SRM dynamo belt drive
« Reply #3 on: 02.01. 2013 14:08 »
Hi Richard
I have had no problems with the SRM belt drive (touch wood) its been in there 7 or 8 years now!!
I believe belt tension is fairly critical???
As Musky says end float could cause problems!!!

Happy New Year
John
1961 Super Rocket
1963 RGS (ongoing)

Online orabanda

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Re: SRM dynamo belt drive
« Reply #4 on: 02.01. 2013 14:45 »
Gentlemen,
Thanks for your responses.
Please share your adjustment procedure?
Richard

Online orabanda

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Re: SRM dynamo belt drive
« Reply #5 on: 02.01. 2013 14:56 »
Just got a response from Gary Hearl at SRM:

"Could be a couple of issues, belt tension too tight when cold, check tension when engine is at temperature and adjust accordingly.
 
If 50w or 60w Halogen bulbs are used, dynamo can overgheat and expand, cauing armature to touch field coil and partially sieze, make sure max wattage Halogen used is 35w.
 
Also pack belt with grease to help lube and keep a little cooler."
 

Online chaterlea25

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Re: SRM dynamo belt drive
« Reply #6 on: 02.01. 2013 15:06 »
Hi Richard,
I have my setup running dry!!!
I set the belt with around 1/4 in slack cold and then checked that it would easily twist 45 degrees when hot
The clamping arrangement wants tighten the tension as the  clamp nut is tightened *problem*
I probably had several go's to get it right  *ex*

HTH
John
1961 Super Rocket
1963 RGS (ongoing)

Online RichardL

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Re: SRM dynamo belt drive
« Reply #7 on: 02.01. 2013 18:22 »
Uh, so rechecking it hot means pulling off the timing cover right after having put it on? Ouch!

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


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Re: SRM dynamo belt drive
« Reply #8 on: 02.01. 2013 19:10 »
 I don't really like the idea of putting grease in there and I tighten to John's specs. The first time I thought the belt was touching the boss for the inner cover screw in the middle. I ground the boss down and use a counter sunk screw. Had another couple go since then. Heat may be one of my problems as I run a std dynamo and dvr2 on 12v mode for the boyer sparkles. I never use my lights but the dynamo is working at a rate of +4 amps once over 30mph.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline WozzA

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Re: SRM dynamo belt drive
« Reply #9 on: 02.01. 2013 22:50 »
Not a solution to your problem, but may be of help to some...
I was put onto this stuff many years ago for belt drives...     wink2
a quick squirt once a year does wonders for the belts..
'51 Golden Flash Plunger
'57 Golden Flash Swingarm

Melbourne
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Online bsa-bill

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Re: SRM dynamo belt drive
« Reply #10 on: 03.01. 2013 11:38 »
My tuppence worth - I agree with all Johns comments especially the trial and error with the clamp.
Mine is the SRM one I run it dry apart from the time the reversed scroll idler bush proved it's worth as a pump and tested the belts oil resistance. (it did not slip)
Only issue I've had was one of the side plates came off the large pulley, found it when in there for another reason, no harm done so put it back on and centre popped it around the alloy hub and it's been alright ever since
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

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Re: SRM dynamo belt drive
« Reply #11 on: 03.01. 2013 13:18 »
 Another product I tried Woz was CRC Belt Grip. Worked good on V's but can't see the point for toothed belts A lube like that (your pic) would be better.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline terryk

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Re: SRM dynamo belt drive
« Reply #12 on: 03.01. 2013 13:26 »
I have just always used the original chain set up with grease for years on a number of different bikes. I haven't had any problems with it maybe I lucky.
1950-53 A10 rigid/plungers, 1958-61 A10 super rockets, 1947-50 A7 longstrokes, 1949 Star twin,
1951-54 A7 plungers, 1940s M21, WDM20s,
1948-50s B33s rigid/plunger/swingarm, 1948-50s b31s rigid/plunger/swingarm

Online bsa-bill

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Re: SRM dynamo belt drive
« Reply #13 on: 03.01. 2013 14:58 »
I had a Flash for maybe two years in early sixties and recall at least three chain replacements, but then I was a young lad learning about things like chain and belt tension and the fair sex, some learning curves are steeper than others I guess and 50 years later I can now do chains and belts  *smile*
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 metalflake11

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Re: SRM dynamo belt drive
« Reply #14 on: 03.01. 2013 17:10 »
I ran the same chain and sprockets for donkeys years with hardly any maintainance or adjustments ever needed. Back end of summer last year, on a whim, I put an S.R.M. belt kit on, after hearing all this I am begining to wonder if I have been wise?
 They advise running it in grease so I do just that, but it does seem an odd thing to do!........... It's like their comprehensive engine re-build guarantee, which is only valid if you run it on straight oil and NO filter. I don't understand that either!........... The bike still has a cartridge filter fitted and it would take very little time, effort or cost to plumb it in, but I don't.
I suppose my point is, for every A10/A7 I have built they will have done 100's. So for me, I ask the question and argue my point of view sometimes, but at the end of the day I follow their advice to the letter. Tens of thousands of miles with very little trouble back their views up. For me, adjust it like they say and pack it with grease!
England N.W
1960 A10
England