The clutches on a Diablo are made by Salsbury. I wrote Salsbury once looking for information and this is what they said:
Dear Bruce:
Thank you for your letter and the Service Bulletin. Salsbury Industries sold the torque converter line of its business in 1993. As such, there are no parts available as all items were transferred during the sale 15 years ago.
Best of luck to you.
Sincerely,
Michael L
SALSBURY INDUSTRIES
Los Angeles, CA 90001-1598
Oh well, it was worth a try.
The primary clutch is Salsbury series 500. However, I’ve also seen this clutch referred to as a series 700, so I’m not sure what the correct designation of it is. The clutch is common used on many snowmobiles of it’s time, but the bore is uniquely small. I believe the taper on the Hirth 54R Special used in the Diablo 500 and 502 along with the taper on the Hirth 190R used in the Diablo 503 is referred to as a 25mm taper. The bore of the clutches is 24mm at it’s widest point. So when the clutch is set on the taper, it’s offset off the motor shaft slightly.
Roy T from Gatineau, Quebec shared this excellent idea to remove the Primary clutch.
How it works – The faster the clutch is spun, the more centrifugal force applied to the roller weights which move the clutch plate in closing the gap and grabbing the belt. If you were to watch it operate at high speed, you would see the belt move toward the outer edge of the Primary Clutch while at the same time, moving down into the Secondary Clutch. The clutch cover is a ramp plate and is also important to operation as the rollers roll against it forcing the inside belt plate to move. Guess that is why they call it a “Ramp Plate”.
These clutches are fairly hardy. Not much to go wrong with them. Common problems:
The faces get oxidized – Being very careful while the engine is running and having the belt removed, I span a piece of emery cloth across the face and it polishes up nicely. Do this at your own risk.
Ramp Plate screws bust off. Does your Primary Clutch have allen headed screws or hex headed bolts? If you have screws, those are original. If you have bolts, your clutch has been updated with a Service Bulletin (copy available in the technical packet). I suggest not to reuse the screws and replace them if you remove them. When you put them back in, the torque spec is 2 foot pounds or 24 inch pounds.
Clutch springs can break and the pins can get worn. If you are lucky, you can locate a spring/pin kit if needed.
Lubrication – I’m use a Comet Clutch Lubricant on the springs and rollers. Light oil or graphite would work too.
The Secondary Clutch is known as a Salsbury 900 Series Torque Converter.
These clutches are also fairly hardy, but if anything, the alignment pins come loose and that can be a problem. Looking at the above left picture, you can see the peened over rivet end of the spacer at 2:00 and 6:30. However, not the rivet at the 11:00 o’clock position. The rivet peen is coming apart and this rivet is loose. Pins can be replaced using shoulder bolts and once installed, cutting off the head.
To pull the clutch apart, push down the cup and remove the snap ring. If you don’t have a jig for this or another good technique, ask someone to push down the cup while you remove the snap ring. Otherwise it will pop off and hurt you.
Once apart, it can be easily cleaned up and lubricated.
If the clutch faces have cracks in them, best to locate a replacement. If the pins are loose or broken, they can be replaced with a shouldered bolt.
The original drive belt for all Diablos is a Bolens 180-1047. As this belt is no longer available and no current manufacturer makes a match for this belt available at retail outlets, Go Go Diablo contracts directly with Gates to reproduce the Trail Runner 6014 Snowmobile Belt.