Suggest a good belt drive kit for my MKIII.

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I want to do a belt drive primary conversion and want to know what a good brand is to go for. You guys have been around Nortons far longer than I have (about 2 months!) so I am looking for insight on this topic.

There are the ones by Norvil, Maney or Clubman and various other manufacturers or resellers selling them. I want something that in case I need a part for it I don't have to deal with something that is not being made anymore. I am leaning towards Norvil but could use a suggestion or two. I would like to buy it within N. America. Canada if possible as the conversion rate to pounds is terrible. Thanks.
 
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Coco

I got the kit from RGM and although i haven't installed it yet it appears to be suitable for the job. RGM had the best price in spite of the exchange rate and shipping. they have two kits one keeps the electric start and the other does away with the sprag assembly (slightly less money and probably less problem since it can be run dry. the kit that keeps the sprag will need to run in ATF to lubricate the starter gears etc) God only knows when i'll get around to installing it but the parts look well made and they do sell replacement parts. the only part that might need repacement should be the belt which appears to be an off the shelf item. I suppose it's the same assembly that Norvil or some of the others sell but there were no brand markings on anything except the belt.
Scooter
 
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Scooter62 said:
the kit that keeps the sprag will need to run in ATF to lubricate the starter gears etc) God only knows when i'll get around to installing it but the parts look well made and they do sell replacement parts.

Thanks Scooter. I did'nt even think about my electric starter needing ATF fluid in there. Sorry for my ignorance as I am new to Nortons and have not looked inside the primary yet. I wanted to do away with any fluid in there to get away from possible leaks ect.

How much ATF fluid needs to be in there anyway for the electric start? Seems rather pointless to do away with the chains just to have fluid in there anyway for the electric start.

Did you alter any of the belt sprocket sizes? Did you also buy a gearbox belt tensioner mount as well?

It seems as though I may have bitten off more than I can chew with this conversion as I may need the tensioner as well which would involve a ot more work.

I checked into the Norvil and it seems to only work with a Sprag clutch which I asume is a brand name. I looked into Clubman Racing as well for their street version and they recommend the tensioner mount as well. I'm stumped.
 
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check old britts also, I bought one from Fred and its a nice piece (very well made) I did away with the elec start on mine as its an exposed primary now. I bought the main shaft support from steve maney because I think it needs the support without the inner primary.

Mark
 
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When I spoke to Les Emery at Norvil about the belt conversion for the MK3, he said it didn't need to run in fluid, and that the maintainence requirements were to oil/grease the electric start components from time to time.

As my Norton isn't quite on the road, I have no user experience to confirm if this is satisfactory, but I hope so, as I have bought one, so that I wouldn't have to run fluid in there. I also got a clutch pushrod oil seal, to hopefully stop gearbox oil getting on the clutch, and so hope that the clutch will not slip anymore.
 
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Reggie said:
When I spoke to Les Emery at Norvil about the belt conversion for the MK3, he said it didn't need to run in fluid, and that the maintainence requirements were to oil/grease the electric start components from time to time.

After pondering what Scooter62 said, I started to think about it. I am thinking you are correct in stating greasing the starter components would be adequate, but some belt kits are indeed made to use with fluid but I want to go the dry route.

Belt + fluid = what is the point of doing a belt conversion.

Reggie, did you do a mainshaft support as well?
 
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Coco

Getting rid of the oil in the primary is the least advantage you will see with a belt drive. The big advantage for a Commando is that the belt drive is much kinder to your transmissions gears. All of that rotating mass from the triplex chain tends to brinel the gear faces, not a good idea. The belt drive assembly is also a lot lighter thereby reducing the overall weight of the motorcycle (minor advantage, but every little bit helps)and rotating mass.
The RGM kit comes with an eccentric mounting bolt for the transmission to adjust tension and they also recommend just greasing the sprag and gears. I'm not going to test their theory for them and at worst may have to replace the belt at some point (a lot cheaper than replacing the sprag). ATF type F should do the job nicely and not affect the clutch plates. We'll see who's right.

Scooter
 
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I was looking at a few kits. Some are for fluid and some not for fluid. The Hayward kits are designed for fluid and the Q.P.D. are designed to be run dry, but apparently the fellow that makes the Q.P.D. kits makes them on a very irregular basis and they don't seem to be available at the moment. That being said, I would prefer to buy a kit from somebody that will have parts available ect. Can I get Norvil anywhere in N. America?
 
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Coco said " Reggie, did you do a mainshaft support as well?"

I assume you mean a gearbox mainshaft support? The answer is no.
I'm just going to bolt up the standard primary chaincase, but with no oil in.
 
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Belt Drive

I noticed that Norvil gives you the option of different clutch and pulley sizes in their kit. I would think that this would affect engine RPM at speed along with the countershaft sprocket. Does anyone have a formula for calculating the optimum sizes for a particular riding style. For example, I have to ride around 40 or 50 miles on the expressway to get to any twisties and If I don't go at least 80 mph, then I'll most likely get run over. I run a 21 tooth countershaft and really don't want to go any higher, but have been considering a belt drive kit. The sizes are just confusing........Jack
 
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Re: Belt Drive

outlaw1875 said:
I noticed that Norvil gives you the option of different clutch and pulley sizes in their kit. I would think that this would affect engine RPM at speed along with the countershaft sprocket...... The sizes are just confusing........Jack

I saw that too and instantly got a headache as I have no idea what ratio to go with. This is getting a tad harder to figure out than I anticipated, but I gues I have the rest of the winter to figure it out. :roll:

Since I am in there, should I bother getting a new clutch plates as well? The little devil on one shoulder is saying yes. The fellow at RGM motors said to rough up the clutch discs if I'm using the kit dry. What do I rough them up with? Emery cloth?
 

L.A.B.

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Going 'larger' on the engine sprocket/pulley and 'smaller' on the gearbox sprocket is supposed to give the gearbox an easier time. The belt kit supplier should be able to give advice about the gearing and the most suitable pulley sizes to use taking into account the rider's own personal preferences which are likely to vary of course.

However there are various gearing calculators available on the Internet which will allow the owner to work out different gearing options.

Example (for Microsoft Excel):
http://www.dropbears.com/u/utilities/gearing.htm
 

MichaelB

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Coco said:
Scooter62 said:
the kit that keeps the sprag will need to run in ATF to lubricate the starter gears etc) God only knows when i'll get around to installing it but the parts look well made and they do sell replacement parts.

Thanks Scooter. I did'nt even think about my electric starter needing ATF fluid in there. Sorry for my ignorance as I am new to Nortons and have not looked inside the primary yet. I wanted to do away with any fluid in there to get away from possible leaks ect.

How much ATF fluid needs to be in there anyway for the electric start? Seems rather pointless to do away with the chains just to have fluid in there anyway for the electric start.

Did you alter any of the belt sprocket sizes? Did you also buy a gearbox belt tensioner mount as well?

It seems as though I may have bitten off more than I can chew with this conversion as I may need the tensioner as well which would involve a ot more work.

I checked into the Norvil and it seems to only work with a Sprag clutch which I asume is a brand name. I looked into Clubman Racing as well for their street version and they recommend the tensioner mount as well. I'm stumped.

I don't understand why you're going to a belt drive unless you are missing parts from the origianl. The Mark III primary is more complex than the others. It already has self adjusting tensioners for the chain.
The Mark III also has a cush drive in the rear hub.
The Mark III also has perimeter screws around the primary for tight oil seal. The others have a single center bolt designed from the 40's.
If you are doing it for oil tightness, that is the wrong reason because the Mark III design is as good as most modern day cycles.

If all the parts are there, I would suggest to leave well enough alone and spend the money elsewhere. This conversion can be done at anytime.

My $.02
 
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MichaelB said:
I don't understand why you're going to a belt drive unless you are missing parts from the origianl. The Mark III primary is more complex than the others. It already has self adjusting tensioners for the chain.
The Mark III also has a cush drive in the rear hub.
The Mark III also has perimeter screws around the primary for tight oil seal. The others have a single center bolt designed from the 40's.
If you are doing it for oil tightness, that is the wrong reason because the Mark III design is as good as most modern day cycles.

If all the parts are there, I would suggest to leave well enough alone and spend the money elsewhere. This conversion can be done at anytime.

My $.02

It would be done to keep leaks at bay and I figured the MkIII would be as leaky as the older design, which I have never seen. I'm new to Commandos so I was going to do a bunch of work to my MkIII over the winter so maybe I will let the belt drive mod ride out for a while. I still want to do it at some point though.
 

L.A.B.

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Coco said:
It would be done to keep leaks at bay and I figured the MkIII would be as leaky as the older design, which I have never seen.

The 850 MkIII primary case design is considerably more oil tight (and stronger) than the earlier type, and probably had to be made so because the primary oil needs to be kept INSIDE the case and at the recommended level, otherwise the hydraulic chain tensioner would stop working properly.

My 850 MkIII engine/primary/gearbox leaks no oil.
 
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L.A.B. said:
My 850 MkIII engine/primary/gearbox leaks no oil.

Thanks L.A.B. I'll probably leave it be then and put the cash towards that new set of wheels I am looking at.
 
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