Sprag survival in Norvil dry belt primary

mdt-son · 2026-08-12T16:16:26-0600

McBrewster said:
Yes, one option is to look at returning to an oil bath chain or or belt which is oil bath resistant.

There is no such thing as an oil resistant belt drive. This was learnt the hard way by the automobile industry years ago.

- Knut

grandpaul · 2026-08-12T16:49:28-0600

mdt-son said:
There is no such thing as an oil resistant belt drive. This was learnt the hard way by the automobile industry years ago.

- Knut

Correct. They resist, and resist, then fail.

McBrewster · 2026-08-12T17:27:45-0600

grandpaul said:
Correct. They resist, and resist, then fail.

Thanks, yes, they are more oil resistant than older belts but not designed for sitting g in a warm oil bath. The advertising of them has been misleading. Understood now.

vidar hjelm johansen · 2026-08-13T02:11:26-0600

Yes, I have used CNW's easy pull kit, with Barnett plates in it, for several years on my MK3. Works perfectly. I think it's been at least three years since I've had them out. That was when I installed CNW's starter and sprag upgrade, which is also absolutely perfect. (When I did that, I dismantled the kick)

Vidar

cliffa · 2026-08-13T06:23:20-0600

nortonmargie said:
yes it is...

In that case as @dobba99 said, absolutely no point doing a belt drive on a MkIII.

Does your bike have the nut on the mainshaft with a built in seal? If not, you may find it’s gearbox oil migrating along the pushrod and into the clutch.

cNw Clutch Rod Seal

Shallow nut CNC machined from alloy Threads are cut to ensure proper clearance between the nut and end of main shaft High quality o-ring (easily replaced) A must for belt drive applications and when using fiber clutch plates 07/16/2026. Due to these being part of my e-start kit and currently...

coloradonortonworks.net

kommando · 2026-08-13T06:47:33-0600

mdt-son said:
This was learnt the hard way by the automobile industry years ago.

Ford Transit etc Ecoblue engine wet belt says they have never learnt.

How long does a Ford Transit wet belt last?

Ford’s earlier guidance for the wet cambelt in the EcoBlue engines was up to 10 years or 150,000 miles. However, real-world experiences show many failures occurring far sooner, between 60,000 and 100,000 miles (or 3–7 years) depending on driving conditions, maintenance regime, and how frequently regeneration events occur. Because of this, Ford’s recommended belt replacement interval has been lowered to 6 years or 100,000 miles. To be on the safe side, many motorhome owners now stick to a 2-year replacement cycle especially if their van spends a lot of time off the road, to reduce the risk of belt damage from oil and fuel breakdown while in storage.

A 2 year replacement at £1400 a time is not cheap.

vidar hjelm johansen · 2026-08-13T07:35:00-0600

yes I have that seal

Vidar

EstuaryBoy · 2026-08-13T10:43:40-0600

nortonmargie said:
As I was scrubbing my clutch plates to rid them of glop, I had thoughts about a belt drive. Reading this thread, I am now resigned to occasional clutch plate scrubbing

I have a set of RGM's 'Hi-Torque' clutch plates awaiting fitment in my Mk3, hoping they will stop all that silly business ;-)

o0norton0o · 2026-08-13T11:25:19-0600

Is there no such thing as a 2RS sprag for this application?? It's too simple of a solution, so I assume the answer is "NO" and there's a good reason why not.... Anyone?

cliffa · 2026-08-13T11:50:43-0600

vidar hjelm johansen said:
yes I have that seal

Vidar

Glad to hear it, but actually the question was aimed at @nortonmargie

dobba99 · 2026-08-13T12:02:17-0600

o0norton0o said:
Is there no such thing as a 2RS sprag for this application?? It's too simple of a solution, so I assume the answer is "NO" and there's a good reason why not.... Anyone?

To furnish a sprag with seals it has to be a self contained unit. Much too big for our application

Sprag survival in Norvil dry belt primary

How long does a Ford Transit wet belt last?​

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