Belt drive questions (2006)

cash said:
Coco,
I've ran an RGM belt on my Mk3 for 13 years, it must have done 40k miles and never needed adjusting for wear or stretch. It's the same belt as fitted to Heywood drives, steel backed and I believe the strongest on the market.
I fitted it like many others to stop clutch slip, and to that ends it failed. The slip and drag is caused by gearbox oil leaking down the clutch push rod. Fit a seal, Norvil do them or make your own, problem solved. The primary ratio on the RGM drive has been changed to speed up the gear box in an attempt to reduce running loads.
Having said all that, I would agree with MichaelB a belt drive is a lot of money to throw at what is in reality a small problem. Fit a seal, a smooth cable, get the stack height right, and you will find the stock primary and clutch are well up to the job, reliable and light in operation.
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I am open to all comments and suggestions, so no one need by wary of saying something as I won't get upset or offended. No worries. :D

I was going to fit a belt drive sooner or later and since I figured I would have everything apart in there anyway to deal with the clutch, I would get the belt drive conversion out of the way. That was my only reasoning to do it at this time, otherwise it would be done by CNW anyway when I get my motor rebuilt by them next winter.

The clutch seal is a good idea, but I am experiencing no leakage and it couldn't hurt to do it while things are apart.

I am however replacing the clutch cable first and trying for a smoother cable routing path.
 
cash said:
Coco,
I've ran an RGM belt on my Mk3 for 13 years, it must have done 40k miles and never needed adjusting for wear or stretch.
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Did you go with their tranny adjusters or are you running it without?

I am not too worried about the extra cash spent on a belt drive. A few hundered dollars is no big deal to me right now and won't break the bank.
 
L.A.B. said:
By 'open' I meant that the clutch is not designed to keep oil out! Brittwin, if you should actually take the trouble to inspect a clutch you should see that the standard Commando drum actually has HOLES in the outer drum circumference where excess oil can escape from the clutch. Oil is NOT TRAPPED IN THE HOUSING BY THE SPRING!
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Of the three Mk.III's I had, only one of the (triplex chain) clutch baskets had a few tiny peripheral "oil escape holes" in them - they didn't look the business.
My first Commando was my regular (almost daily) transport for ten years, the second and third were bought as "spare parts carriers", but I eventually also restored the latter two. I sold all three Commandoes (all Mk. III's) between 1991 and 2002 due to heavy, painful spine problems (intervertebral discs) emerging, causing considerable immobilisation. I just mention this to tell you I've been working intensely on Mk.III Commandoes for 17 years..... :wink:

L.A.B. said:
If that truly was the case then the plates would slip as soon as they got oil on them, and I am sure from my own experience and reading about the experiences of others (here and elsewhere) that there are many Commando owners that still have standard clutches fitted and experience no problems (myself included) under normal conditions, but yes I do agree they can benefit from an *ocasional* clean up.
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The "clutch slip" problems of my frist stock MK.III became noticeable after some time / mileage, I rode this bike for 10 years and over 75,000 mls), and I always encountered clutch slip after, say, every 2,500 - 3,500 mls. A thorough cleaning job then recftified matters for another 3,000 mls. I also used a home-made pushrod-tunnel seal which did a perfect job, so gearbox oil entering the clutch wasn't the problem. After approx. 15,000 mls I got tired of all this and a Norvil belt drive kit with "sureflex" fibre friction plates (running dry) cured the problems.

L.A.B. said:
Can bronze and steel become 'soaked'? I am not trying to infer that the clutch would not work better dry I am just saying that it does generally work OK as it is.
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The Mk.III "bronze" clutch plates are a porous sinter material job which tends to keep oil in it, thus "sweating it out" when becoming hot (friction!), a desirable property of bearing materials but no good for clutch plates. After becoming aware of this, I regularly cleaned the bronze plates in a solvent bath (acetone) for approx. 12 hrs, which thoroughly removed the oil. However, the improvement was minimal - it simply gave me, say, 500 more "slip-free" miles.
The Norvil belt drive kit gave me approx. 20,000 maintenance-free miles (first leg) instead, I only had to open the primary drive after that mileage to replace the final drive sprocket (worn), and the (sealed) clutch roller bearing (a a precaution). Then the bike was good for another 35,000 mls (second leg), and even after that time the belt hadn't shown any significant signs of wear whatsoever. Quite impressive, IMHO.

L.A.B. said:
Yes obviously, but from what you originally said you appeared to infer that the hydraulic tensioner was a common fitment to Commandos. I was merely bringing this to the attention of anyone who might have thought that.
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Sorry for conveying that impression, I was of course solely referring to the Mk.III OEM primary drive. IMHO it makes more sense to replace a MK.III's primary drive train with a belt drive kit than that of earlier Commandoes - because it simply eliminates more problems and maintenance issues therewith.
I think that actiually riding a Commando a lot makes it a very desirable achievement to get at least partially rid of it's archaic, intensive maintenance scheme, giving it a more favorable ratio of "mainteance & repair vs riding" hours. That is to say "ride more, and have less problems to fix". In due course, I advocate electronic ignitions, automatic cam chain tensioners, and of course primary belt drives as well as other, unobtrusive improvements which are not too obvious to the naked eye. A matter of individual "taste", if you want, and certainly nothing a Commando owner would want to do if he'd like to keep is bike "100% stock/original".
 
[quote="brittwin] The Norvil belt drive kit gave me approx. 20,000 maintenance-free miles (first leg) instead, I only had to open the primary drive after that mileage to replace the final drive sprocket (worn), and the (sealed) clutch roller bearing (a a precaution). Then the bike was good for another 35,000 mls (second leg), and even after that time the belt hadn't shown any significant signs of wear whatsoever. Quite impressive, IMHO.[/quote]

Brittwin (or anybody), do you suggest a clutch roller bearing replacement when I replace my clutch and instal a belt drive in my MkIII ? Sorry if this is a dumb question. Is this a hard thing to do?
 
Coco said:
Brittwin (or anybody), do you suggest a clutch roller bearing replacement when I replace my clutch and instal a belt drive in my MkIII ? Sorry if this is a dumb question. Is this a hard thing to do?
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Normally a new bearing comes as part of the kit, especially if it is a 'dry' belt kit as these need to use a sealed bearing.
 
I think that actiually riding a Commando a lot makes it a very desirable achievement to get at least partially rid of it's archaic, intensive maintenance scheme, giving it a more favorable ratio of "mainteance & repair vs riding" hours. That is to say "ride more, and have less problems to fix". In due course, I advocate electronic ignitions, automatic cam chain tensioners, and of course primary belt drives as well as other, unobtrusive improvements which are not too obvious to the naked eye. A matter of individual "taste", if you want, and certainly nothing a Commando owner would want to do if he'd like to keep is bike "100% stock/original".[/quote[


I agree with this way of thinking in general, however as long as it remains trouble free, I will hang onto the stock primary and clutch. I also like using the electric start which I assume would be lost with a belt drive conversion.
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No, this is not the case.

I have just fitted a (Norvil) belt drive to my MK3, and have kept the electric starter which works very nicely at the moment. I cannot say if the belt width, or sprocket ratios are compromised in any way to accomodate the starter mechanism, I'm sure somebody else can advise on this, but I wouldn't think they would be.

Incidently, I have also seen a belt failure on my friends Commando (that I had built for him in approx 1990). It was I think one of the first RGM belt drives as far as I recall, and the dural sprocket wore quite badly, before shredding the teeth on the belt. As far as I am aware all these issues were quickly addressed at the time, and I would assume that RGMs belt drive kits have been reliable since shortly after this time.



Reggie
 
L.A.B. said:
Coco said:
Brittwin (or anybody), do you suggest a clutch roller bearing replacement when I replace my clutch and instal a belt drive in my MkIII ? Sorry if this is a dumb question. Is this a hard thing to do?
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Normally a new bearing comes as part of the kit, especially if it is a 'dry' belt kit as these need to use a sealed bearing.
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I figured that was the bearing Brittwin was talking about but was unsure. Thanks for the confirmation L.A.B.
 
Reggie, does the antikickback system also stay in place with the belt drive?
 
Reggie said:
No, this is not the case.

I have just fitted a (Norvil) belt drive to my MK3, and have kept the electric starter which works very nicely at the moment. I cannot say if the belt width, or sprocket ratios are compromised in any way to accomodate the starter mechanism, I'm sure somebody else can advise on this, but I wouldn't think they would be.

Incidently, I have also seen a belt failure on my friends Commando (that I had built for him in approx 1990). It was I think one of the first RGM belt drives as far as I recall, and the dural sprocket wore quite badly, before shredding the teeth on the belt. As far as I am aware all these issues were quickly addressed at the time, and I would assume that RGMs belt drive kits have been reliable since shortly after this time.



Reggie
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From my understanding the starter can be used but it is the sprag (bearings?) on the starter that might wear out due to lack of lubrication when going with a belt drive. I could be wrong but it makes some sense if the starter overheats that it could cause premature bearing failure. I really dont see how it would effect things negaitively as long as there is some venting provided and the bearings in the starter are in good shape. RGM mentions the electric start can be used occasionaly with the dry belt drive so I am going with a 4 brush prestolite starter and the bearings are really uprated compared to the original.

I have decided to go with the RGM belt drive over the Norvil. I know a few people have told me the Norvil belt drive kits are better than the RGM model but I think at this point both are probably quite good. I have asked RGM a million questions via e-mail so I feel obliged to give them some of my business. Ordering an extra bearing and belt with the kit probably couldn't hurt either.

There has been a lot of great information shared here so I am glad I revived this thread.
 
This makes sense, I can't see the sprag going all that long without lube. When the sprag lets go, it can really ruin your day. As I found out, it can jam things up completely, requiring more involved work than you want to do roadside.
 
worntorn wrote "Reggie, does the antikickback system also stay in place with the belt drive?"

Yes it does retain the anti-back fire device.

With regards to the sprag bearing running dry, I don't know if it will advesely effect this bearing to any significant level except maybe in the long term. When I asked Les Emery about the starter train and lack of lubrication with a belt drive system, he said that car systems run dry with no problems! I know that this is a bit of an over simplification but he suggested greasing the components periodically.

I understand worntorns concerns about the sprag bearing, as I understand it, the bearing is not working as such except when you are starting the engine. Surely when the motor is running, the roller faces run against the sprocket inner faces with very little contact, hence the engine is not engaged with the starter train?

Coco wrote "RGM mentions the electric start can be used occasionaly with the dry belt drive." There was no restricted use of the starter motor mentioned to me by Les Emery, and if this turned out to be the case, I would revert back to a chain.

I will not be running my Norton before April very much (due to salt on the road). If it self destructs when it starts getting some use, I will update you all!
 
I just talked with the owner of British/Italian MCs on this subject. He has owned and ridden Commandos since they first came out and was a mechanic for British Motorcycles in Vancouver. He later bought British Motorcycles and now operates it as British/Italian. They have a good stock of Norton parts and he is extremely knowledgable on the Commando. He tells me that belt drives work well and are a good upgrade on old Triumphs as they have a very weak primary, and fast wearing sprockets. He says the stock primary on the Norton is very strong, the chains and sprockets are extremely long wearing. He also said that the Norton clutch is overengineered and can handle over 100 HP when properly setup.
He pointed out that the Atlas had essentially the same engine running thru a single row primary whereas the Commando was beefed up to a triplex, and seems more than up to the job. He wasn't sure how well the sprag would live without lube, but wondered why one would want to go this route.
He said he will sell me a belt drive if I really want one though.
Not really a hard sell kind of guy, which is nice.
 
Reggie said:
With regards to the sprag bearing running dry, I don't know if it will advesely effect this bearing to any significant level except maybe in the long term. When I asked Les Emery about the starter train and lack of lubrication with a belt drive system, he said that car systems run dry with no problems! I know that this is a bit of an over simplification but he suggested greasing the components periodically.
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I think you are right here. The RGM snippet was simply from their catalog and when emailing RGM they said the same thing that Mr. Emery told you, an occasional greasing will suffice.
 
worntorn said:
He said he will sell me a belt drive if I really want one though.
Not really a hard sell kind of guy, which is nice.
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Do you know what brands of belt drive kits he sells? I would like to avoid ordering from England since the pound vs. the Candian dollar is pretty ridiculous right now.
 
He mostly uses Norvil stuff, but has some other suppliers as well. For small orders I go to him since he is local and has a good stock. He is more expensive than Norvil though, but sometimes I don't want to wait for parts.
 
I don't have a vast knowledge of cars but I have only ever come across two basic types, the old Bendix system or the "pre-engaged". Both rely on all parts of the starter assembly being completely withdrawn from contact with the ring gear.

I would assume that when the Mk111 is running, the sprags fall away from the sprocket and rest on the idler. The needle rollers in the idler gear are however working at (up to) 7000 rpm and I can't imagine that a bit of overheated grease is going to keep them in good condition for long.

The horrible noise that one hears when a Mk111 motor stops is presumably the sprag running on at a higher speed than the idler, at which point there is probably a light metal to metal contact.

If the aim of a belt is to reduce noise then I don't think it's going to be achieved with all the starter bits whizzing around in the chaincase.

I'm certainly not joining the queue to be one of Les Emery's unpaid devlopment testers :D
 
Reggie said:
When I asked Les Emery about the starter train and lack of lubrication with a belt drive system, he said that car systems run dry with no problems! I know that this is a bit of an over simplification but he suggested greasing the components periodically.
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I'm slightly surprised Les Emery would say something like that, as car starters normally work differently, using either inertia or pre-engaged type starters that completely disengage the starter drive when not actually turning the engine. Perhaps Les does not know so much about cars?

Coco said:
I could be wrong but it makes some sense if the starter overheats that it could cause premature bearing failure. I really dont see how it would effect things negaitively as long as there is some venting provided and the bearings in the starter are in good shape. RGM mentions the electric start can be used occasionaly with the dry belt drive so I am going with a 4 brush prestolite starter and the bearings are really uprated compared to the original.
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I certainly cannot see there being any way that operating the starter could cause any damage whatsoever to any part of the drive train by it becoming overheated, as the battery would be flattened well before that happened!

79x100 said:
I would assume that when the Mk111 is running, the sprags fall away from the sprocket and rest on the idler. The needle rollers in the idler gear are however working at (up to) 7000 rpm and I can't imagine that a bit of overheated grease is going to keep them in good condition for long.
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Once the engine starts and the sprag disengages it would appear to be free to float about, although the late type sprag I fitted had clips that locate it lightly to the sprocket so I would expect it to (more or less) rotate with it.
The only concern as has been stated already would be the idler gear needle roller bearing which is held static (after electric starting) except for its inner race which rotates with the crankshaft, although there is no actual load on the bearing at all once the engine has been started, but it certainly would need to have at least some lubrication present.
 
OK here's my 2 pence worth;

I have the RGM belt drive for the MK III and got the same advice from Roger at RGM: "just grease the sprag assembly ocassionally and it will be allright". Some how i just don't believe that, besides it just aint that easy to get to the sprag assembly once you've got the whole thing put together.
My plan will be to run ATF type F in the primary and keep my fingers crossed that the belt (which appears to be steel reinforced Polypropelene) will hold up. In any case a new belt is a lot cheaper than the sprag assembly.

Back to the reasons for switching from triplex to belt;
first the triplex isn't all that perfect, it weighs at least five lbs. more than the belt assembly and thats rotating mass, if it lets go your buying new primary cases (outer cases are getting harder to find, good news is this doesn't happen too often) Next and best reason, as has been previously mentioned the the transmission will thank you (that heavy triplex beats the crap out of the gears) and finally for the MK III you get rid of the almost usless "hydraulic" tensioner.

I have a feeeling that the belt drive kits for the MK III's from either Norvil or RGM are somewhat experimental so good luck Blokes and keep us informed of your progress.

Scooter
 
Scooter62 said:
I have a feeeling that the belt drive kits for the MK III's from either Norvil or RGM are somewhat experimental so good luck Blokes and keep us informed of your progress.

Scooter
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I don't think they are an experiement as RGM and Norvil have sold hundereds of belt kits for the MkIII. I know the fellows at CNW put belt drives in all of their rebuilds, including MkIII Commandos. I do see where you are coming from since the jury is still out whether it is indeed a wise move moving to a belt. My reasoning is as yours; releive stress on gearbox and illiminate some rotating mass. Isn't experimenting half the fun?
 
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