Is venting required for Belt-Drive primary?

My primary runs a Haward belt drive, and I use 20w50 lube in the primary. No problems, but I've been considering running the primary without lube.
If I do, is venting required for cooling? If I decide to keep using lube in the primary, should I be using something else....would ATF work well with a belt drive?

From what i have researched on the Hayward units, they like a 10w, or ATF or fork oil.
This being said, you have the option of running it dry as long as you DO NOT use the slipper tensioner AND venting will be required.

Exerts from installation instructions,


Do not use a slipper tensioner if system is run dry. And if you run dry you need air ducting.

When you have a choice of chaincase oil do not use multigrade – use thin 10 or 20 grade – maybe fork oil – or auto gearbox transmission fluid.

Interesting ..........

I have been running a belt primary for the past 12 years, not a Hayward, just a standard belt Norvil I think.

I run it dry, no lube, and no venting at all. I live in the southwest US, VERY hot and dry hear, routinely ride at
100 degrees, NO "issues" of any kind, in fact I just changed out the old belt after 12 years and some 20K miles.

But why would the Hayward belt "need" some lube slopped on to it? Why is that belt different from others?

The purpose, to me, of running a belt primary is to completely eliminate any possibility of lube getting into my clutch, in addition to putting a final end to oil leaks from out of the primary cover.

Adding lube to the primary seems to be adding lube to the clutch and plates, necessitating cleaning, etc.

But again, why would one "brand" of belt, a Hayward, be so different to specify the need for lube on it?

As far as venting the primary, in my experience, not necessary at all as once the baskets and engine plates heat up all the cold setting slack is taken out, it cannot get any hotter, and high heat by itself does nothing to degrade or accelerate wear to the belt itself. Those belts are damn tough.

I replaced my belt after 20K miles for no good reason, just felt like spending some money on my Norton.

AMC shift imprinted, is completely correct and exactly my own practice on Ms Peel and triple checked from Kenny Dreer to Steve Maney to run belt and charger tight sealed so water crossings and THE Grit don't get inside. Chain drive need a fluid to carry off the link heat and its metal dust, but not actually lube as most might think.
There is no lube possible on in chain drive as links/side plates are not moving fast enough to create oil wedge and are pulled tight to metal-metal contact. If heavy oil used in fast run chain primary it will seize as racers found until they lighted up to 20 grade oil then the heat could be removed w/o link seizure. BTW the "W" stands for Winter grade not 'weight'.

Dry belts are the cat's meow with less friction and mess that way too.
Set tension so long runs can just be twisted to 90's w/o hurting finger tips.
Double check as it warms up to be safe form bending shafts eating bushes.

1up3down said:

Interesting ..........

But why would the Hayward belt "need" some lube slopped on to it? Why is that belt different from others?

The purpose, to me, of running a belt primary is to completely eliminate any possibility of lube getting into my clutch, in addition to putting a final end to oil leaks from out of the primary cover.

Adding lube to the primary seems to be adding lube to the clutch and plates, necessitating cleaning, etc.

But again, why would one "brand" of belt, a Hayward, be so different to specify the need for lube on it?

As far as venting the primary, in my experience, not necessary at all as once the baskets and engine plates heat up all the cold setting slack is taken out, it cannot get any hotter, and high heat by itself does nothing to degrade or accelerate wear to the belt itself. Those belts are damn tough.

Click to expand...

The belt does not need lube. The tensioner on the 75's do. I do not know exactly what singring has but it is quite possible that he has never needed lube in his belt drive system.
As far as venting is concerned, it is just what Hayward recommends. It may be not needed either.

The real issue to understand is that a belt drive -Can Be Run- with oil sealed in so hydraulic devices can function too. Venting is decorative only as by far most the heat is being conducted from the crank shaft and clutch basket and surrounding Al cases radiating inward as much as outward. Venting is not bad idea just useless one.
Oil inside just evens out the hotter spots faster than otherwise. A temp check with and w/o oil would be informative someday to discuss.

I assume singring's Commando is a pre 1975 because belts are not fitted to Mark 3s. Or can they be?

But, he states he IS running his belt primary with lube.

The question is why, anyone know if there is some difference in the manufacture of his Hayward belt that necessitates lube being specified?

Just curious, because any unnecessary lube in our belt (dry) primaries are simply sources of unwanted clutch plate contamination.

There is a little confusion here. Hayward does not require lube for their belt drives. Many other motorcycles had idler type tensioners (T120), that require oil, not the belt.
I believe that singring was either following these instruction or the PO had it that way when purchased, or maybe god only know.
Hopefully singring will chime back in and enlighten us.
But, Hayward belts themselves do not require lube. It does sound like heat has caused belts to come apart from hub expansion. The A10 synchroflex are more robust and heat related expansion can cause other things to fail (mainshaft) before the belt comes apart.

The Dreer sold belt drive in past Peel photo was a Hayward unit. I'd like to see the evidence A10 is more robust.

Thanks for all the quick responses....bike is a 1973 850, and yes PO had lube in the primary. I see concensus is to run dry, which is fine with me...as far as venting, if not required then great....but I did see on eBay a while back that someone had opened up the larger primary access plugs and fitted metal mesh screening, so that venting was possible....turning slots were still there along the outside edges...I thought that was a cool idea, but I just tried to find them on ebay, and no joy.

hobot said:

Click to expand...

The Dreer sold belt drive in past Peel photo was a Hayward unit.

Hayward selling Norvil units or the other way around :?:

singring said:

Thanks for all the quick responses....bike is a 1973 850, and yes PO had lube in the primary. I see concensus is to run dry, which is fine with me...as far as venting, if not required then great....but I did see on eBay a while back that someone had opened up the larger primary access plugs and fitted metal mesh screening, so that venting was possible....turning slots were still there along the outside edges...I thought that was a cool idea, but I just tried to find them on ebay, and no joy.

Click to expand...

You can find the mesh primary plug vents on "Eurotrash Jambalaya" website, I have a set installed. A bit pricey but they look good.

Hello all

Apologies for asking a Triumph question on a Norton page but you chaps seem to have more answers.
I am currently fitting a belt drive to my pre unit 650 thunderbird 1961 and was just about to get my drill out and vent the primary case.
Until i read this page.
In your opinions would the same go for my bike? ie no venting needed.

regards

boko said:

Hello all

Apologies for asking a Triumph question on a Norton page but you chaps seem to have more answers.
I am currently fitting a belt drive to my pre unit 650 thunderbird 1961 and was just about to get my drill out and vent the primary case.
Until i read this page.
In your opinions would the same go for my bike? ie no venting needed.

regards

Click to expand...

I believe this depends on the make of belt drive you are using. The hubs of the RGM unit tend to swell a bit more that others requiring some ventilation to keep things properly adjusted. Too tight of a belt drive can be very bad for crank and gearbox shafts and/or general clutch functionality. Other makes like the Maney, so I have heard, are not so conducive to swelling.

I would suggest trying what you have and adjust slightly on the loose side, go for a ride all covered up and then check the tension before the hubs can cool. THEN, make you determination if venting is required. Simply put, some do, some don't.

I'll give it a go, its a german synchroflex belt from burton bit bits in the uk.
many thanks for the reply

hayward's are designed to be able to run with or without oil

Installed the R.G.M. belt drive on Crazy Combat and went for her first ride. Got about a mile then turned back with clutch problems.Aluminum bits in the basket and in plates and no where else. Took out clutch to observe that the clutch center had been wearing at the basket piece right behind it. This clutch center as we all know is held in by a large circlip to the back and is fully home and non-adjustable ,not a shim situation.Sun well on the sealed bearing before and after this event so I cleaned out the bits and re-assembled for a short ride,seemed O.K. Has this happened to others, heat expansion ?

I have a Bob Newby Racing belt drive for the Norton 650 SS and one for the 1360 Vincent, haven't installed either yet. The plan is to run them both dry.
On the venting question, Bob was a bit vague. His response was that a belt drive runs much cooler than a chain.

If heat is not a concern, then I think the sealed up or mostly sealed up method is preferred for all of the reasons listed by other posters.

I'm really forward to cleaning every spec of oil out of those tin primary covers on the 650 and putting it together dry. I have never had any luck sealing the oil in and I think that is common with all of the tin primary bikes.

With the 850 MK 3, the primary is sealed up tight, no oil gets out and everything works fine in there, so I don't see any advantage to converting it to belt drive, just expense and work for nothing.

Thanks but primary plugs all in place as suggested back when . I will try to find a more relevant post topic if/when search becomes free.

Torontonian said:

heat expansion ?

Click to expand...

You bet your ass it does. That belt needs to be loosy goosy just short of jumping teeth on the front sprocket when kick starting. Seems RGM has made improvements as of late, but I bet they use the same material as before.

Some say they don't heat up and expand and some say they do. Mine most certainly does and I compensate for it as needed with a sloppy belt to start and copious venting in the cover. But don't take my word for it. Just keep sweeping up those bits till there's none left to sweep. What's worse is a possibility of a busted main shaft looming just behind those bits if belt tension not addressed.