Date: Fri, 19 Apr 1996 18:42:31 -0400
From: Gary Slabaugh
In a message dated 96-04-19 12:56:18 EDT, you write:
>2. When checking the oil in the primary case, should the bike be on
the
>side or centre stand??
Centre Stand.
And according to Brian Slark, who worked for Norton when these bikes were new, the correct amount of lubricant of your choice in the primary chain case is not 7oz as stated in some manuals nor should it be filled up to the level plug. 5oz is all that is needed in there. This is what I have been using in several Commandos for many years and helps keep the bike oil-free on the outside while still keeping everything inside the case that needs oil (chain and clutch basket bearing) well lubed. I currently have a primary chain with 38K miles on it and it never needs adjusting.
Gary
Date: Thu, 2 May 1996 07:46:27 +0000
From: John Pinkham
David Jackson laments about his Commando belt drive,
>
>....... Still I think a belt drive
>is a good mod, reducing weight, noise and clutch slip.
>
>Problem is last time I tried one it was quickly reduced to fluff by
torque
>pulling the belt outwards and chaffing against the belt guides. I
tried
>offsetting the gearbox mainshaft against the crank slightly as suggested
by
>the supplier, and inserted a second gearbox adjuster to hold it there.
Still
>no joy. The belt just kept on riding outwards. I had to admit defeat
and
>return to the chain.
>
>What can be done then to prevent this "give" in alignment and is there
>anything to be done while the bottom end and gearbox is in bits? Or
should I
>just stick to a trusty triplex chain?
I've had some grief with my RGM belt drive on a '74 Commando. First problem was caused by tensioning the belt excessively. I thought that drive belt deflection should be measured similar to that of a car fan belt. Push down hard at midpoint between the pulleys and measure the deflection. After shredding belt #1 in about 45 seconds (wedged some lovely steel reinforcing wires between the alternator rotor and the stator), I tried to get the proper deflection by moving the gearbox as forward as possible. Still couldn't get the proper slack (drive belt deflection is to be measured when then clutch pulley just comes under load as the belt is pushed down at belt midpoint i.e. one hell of a lot looser than a fan belt). The inability to get the right slack was caused by two things:
1. The stock gearbox adjuster had fallen off the bike and I had replaced its large bolt (having ground flats where it mates with the slots) with a plain round bolt and a mess of washers. Bad idea.
2. The 890mm belt is almost too short when the stock gearbox adjuster bolt's ground flats are as far forward in the slots as they will go. With no ground flats on the bolt, the belt is too tight.
The second problem was that I followed RGM's instructions literally. They said that a retaining circlip "is now fitted at the factory". Well, it wasn't, as I should have noticed. I should have removed the circlip from the stock clutch and used it. Lack of tthis probably caused the driven pulley to drift out of alignment and started the belt shredding.
Stage Two involved getting a longer drive belt (920 mm versus 890). This belt was *too* loose. No joy.
Stage Two and One-Half involved fitting RGM's dual gearbox adjuster. After labouring to get it in, I found that the left adjuster was un-adjustable on a street bike. Roger Myers [RgM] explained "Oh those are for race bikes. We've never actually tried one on a street bike. Hmmm.
Yes, I can see that there's no way to actually adjust it. Good point!"
I now have the correct gearbox adjuster and a 890mm belt, but the gearbox is disassembled for new close ratio gears. I'll let you know how it works.
John