Belt primary types?

[alanp]

Does anyone run their belt drive primary dry and if so is the drive take up smooth? If so, what type/supplier of drive is it.
I ask this because I took my Hayward belt drive off since run dry the drive take up when warm was jerky and dragged when stationary in gear no matter how I adjusted the cable, the springs or clocked the pressure plate to run true. I'm back to chain and oil in the casing complete with oil drips since what is the point of the expense of belt drives if you need to run with oil? I feel it is just the clutch that the Hayward system uses which is a later Triumph type since I didn't have this trouble with a Bob Newby clutch on my previous Gold Star where the clutch friction plates were one piece Ferodo type friction material and not friction pads on steel plates.
Thanks
Alan

[beezalex]

Hmmm, when you say the takeup is jerky, do you mean it grabs?  Now, I haven't had one on a pre-unit, but the Hayward drives I've used on the unit twins worked really well and I know several people running Haywards on goldies and they work great.  My guess is that there's something else going on.  One guess is basket bearing or maybe a bad cush drive?  I wouldn't give up on this...and maybe you should just call Tony Hayward (no, not the BP one).

[alanp]

Hmmm, when you say the takeup is jerky, do you mean it grabs?  Now, I haven't had one on a pre-unit, but the Hayward drives I've used on the unit twins worked really well and I know several people running Haywards on goldies and they work great.  My guess is that there's something else going on.  One guess is basket bearing or maybe a bad cush drive?  I wouldn't give up on this...and maybe you should just call Tony Hayward (no, not the BP one).

Jerky in my case means that whereas the oiled chain drive feeds power smoothly while slipping to take up the drive in a predictable way, the dry clutch doesn't take up the drive in a progressive predictable way.
There aren't any changes in the rest of the clutch operating system i.e. cable/push rod, and the oiled chain drive is back to normal smoothness.
Did yours run dry or in oil?
All parts are new and in top condition as supplied (apart from the oil thrower thread on the clutch centre adaptor being the wrong hand that is, which wouldn't matter if it ran dry).
When I bought the kit Tony was a bit reserved about running it dry but I thought this was just to cover potential problems with clutch centre bearing life.
I'm prepared to put the kit on the shelf and go for another type, provided that I am confident of a good result.

[muskrat]

G'day Alan,
               sounds like a warped plate or the plates not sliding in the basket or hub properly. It doesn't take much to make them grabby.
I have a dry belt system with a diaphragm clutch (Norton) from Lytedrive in Melbourne. Not enough O's in SMOOOTH.
Cheers.

[beezalex]

All the applications I've ridden were dry.  As you say, running a belt in oil seems pretty pointless since it defeats a major advantage of the belt.  I think this is mainly to soothe the late model triumph and triple owners that would have to make major modifications to their primary to make it run dry.  That said, when you drop the clutch, it stays put on one of these multi-plate deals.  Just out of curiosity, how many plates are you running?  Also, are you running a center-guided pressure plate or a stock steel one?

[alanp]

Alex, I've attached a photo of the clutch plates and pressure plate. It's not centre guided. Any idea where I can get one? If I could get one that would fit this clutch I'd give it a try.

[beezalex]

SRM, MAP, Lyford classic spares, most alloy pressure plate kits for triumph and BSA unit twins come with a guide pin that goes about 1" into the pushrod tube channel in the mainshaft to makes sure that the pressure plate lifts off square.  I think that any of the belt drive kits should come with one of these (I think the Newby drive does?) as these things are otherwise pretty prone to grabbing.

Hope that helps.

Oh, one more thing...your belt tension is set correctly, right?

[alanp]

Thanks Alex. Yep, I checked it a number of times as well as varying it a little and also varying the amount of clutch spring pressure.
I'll track down an updated pressure plate.

[chaterlea25]

HI Alan,
That clutch setup is a new one on me!!!!, It looks as if the centre is just the standard Triumph/ BSA, 3 spring with a basket that takes "Japanese style" plates,
I dont know if these are suited to rumming dry????
I have a couple of friends who have "modern" clutches in their Vincents, these can be wet or dry, depending if the seal behind the clutch is fitted or not
wet they slip and dry they grab
The cure is to rub the friction plates with some ATF every so often with a dry setup 

If the belt you have is suitable to run in oil, its not too big a deal to sort out the sliding plate to make it seal
I turned up a new centre for the sliding plate with a groove in it for a quad ring
the ring runs on the part of the shaft adaptor inside the scroll.
I remember you saying your adaptor is one of the ones with the scroll the wrong direction??
These are not that hard and the scrolled bit can be machined off, then make the sliding plate centre to suit
You could even fit a proper lip seal??
I replacd the felt on the sliding plate with a cork gasket, which I glued to the case and used non setting gasket goo on the plate side
The upshot of this was that I had to fit a breather tube to the primary filler plug as pressure built up inside as the bike heated up 

This has worked fine for me for over 10,000 miles

HTH
John O R

[alanp]

Thanks John.
Re the scroll thread, I've had it machined off and replaced with a sleeve with the correct LH thread. It's just that I didn't want oil in the primary casing at all or I would have not spent the money on a belt drive.
I have a new pressure plate on the way from SRM to replace the pressed steel version with the kit, to perhaps help the plate to remain running true, which I will try dry. If that fails I'll oil the blighter!
Wish me luck, I think I'm going to need it!

[a101960]

I have the SRM clutch plate and radial bearing. It works very well. You will have to shorten the operating rod, and harden it though.

John

[bsa-bill]

Hi Alanp - you'll love the alloy pressure plate, great bit of kit

[beezalex]

Oh lordy...oil the plates on a dry clutch?  Isn't that kinda like oiling your brake shoes?  Loosening up your SRM oil pump to reduce the pressure?

If it's just applying to hard, perhaps reducing the spring pressure is in order...

[alanp]

Oh lordy...oil the plates on a dry clutch?  Isn't that kinda like oiling your brake shoes?  Loosening up your SRM oil pump to reduce the pressure?

If it's just applying to hard, perhaps reducing the spring pressure is in order...

Alex, I've tried variations in spring pressure - no luck.
The SRM pressure plate has arrived now and looks nicely made. Here's hoping.
The next job on the bike though is to replace the knackered 10mm wide dynamo belt drive with a 15mm version from Dynamo Regulators Ltd and replace the V Reg 11 with a DVR3.

[chaterlea25]

Hi Alan/Alex,
Alex,
""Oh lordy...oil the plates on a dry clutch?  Isn't that kinda like oiling your brake shoes?  Loosening up your SRM oil pump to reduce the pressure?""

Wiping the plates with a little ATF just knocks the harshness off the drive take up, its not oiling as such
Anyway it works on the Vinnies
I know that usually there are "different" type plates for wet and dry clutches, so I wonder if the ones in Alans belt drive clutch are suitable for dry running???
You will need some high temp grease for the radial thrust bearing also the chainwheel bearing if running the case dry

Regards
John O R