Griffon clutch question

[Stan Nicholson]

I have been working on the Griffon clutch on my Silverstone and have a question about the 6005 bearing that the clutch basket runs on. As removed from the bike this bearing was rough to turn and I figured the races must be pitted, especially as it was a very tight fit in the basket. Also there was little evidence of oil in the bearing. When removed and washed out, the bearing is fine and the roughness was caused by clutch crud that had accumulated in the open bearing.

My question is, do Griffon owners fit a sealed bearing in the basket and rely on the grease lubrication or use an open bearing and clean it out regularly? My local industrial bearing supplier has this bearing in stock with the double (rubber?) seals that I usually pick out if I need an open bearing, but should I? As the minimum amount of oil in the case is to lubricate the primary chain only and the bearing is pretty much out of any oil splash that might occur, would a sealed bearing be a better option?

Thank you,
Stan

[Dogsbody]

Stan, I have been taking out one of the seals, but like you have considered leaving both in. A wheel bearing, usually a 2RS, will do infinitely more revolutions and we never give it a second thought. I would fit a 2RS and see how it goes. As regards it collecting crud, I suspect it acts like the centre of a C90 type clutch which needs cleaning out regularly as it is designed as a centrifugal oil filter. Colin

[46T Sprocket]

I've had no problem running the bearing with both seals in place. Splash gets the oil to the bearing and seepage does the rest. The good thing about the double seal is that it keeps out any particle that are too large to get past the seal. I do change the oil more often than usual though. It's a mucky place in there..

Just be sure you use the correct bearing type with the standard clearance and not C3 clearance. C3 allows for axial play.

I'm currently using a double row bearing that fits with a slight modification to the spigot in the pressure plate that it sits on. It lets the basket run with less play than a standard bearing. Again with both seals fitted. Not cheap though! See https://simplybearings.co.uk/shop/p1...duct_info.html

[PeterJGreig]

Sounds like a good idea, but, I find the Griffon clutch far too heavy and as my ISDT bike does not produce Griffon power do not see it needs to be- anyone know of a source of lighter springs? Is there a drawing of the correct spring compressor, my home made one is a bit of a bodge?

[druid]

Personally I leave the seals in, not to keep the lubricant in but to keep the debris out. The only time the bearing has to work is when the lever is pulled in so there's little load on the basket.
Regarding using one of 46T sprocket's bearings, as he said its not a straight swap and at over 10 times the price of the standard 6005 2RS I wouldn't think it was worthwhile.
As for the bearing clearance, it depends what the supplier has in stock. Also any clearance is subject to the degree of interference in the clutch basket which can't be guaranteed with an original basket. Most people using the Griffon clutch for either racing or motocross tend to use the standard set up without problems.
The reason Greeves built the Griffon clutch to replace the Albion one was because it was lighter and more durable, not because it handled more power although it does. The 360 used an Albion clutch.
You could make the springs lighter although that may invite clutch slip or increase the leverage ratio on the handlebar lever or simply build up the required hand muscles.

Druid

[Stan Nicholson]

Thank you everyone. I will fit a sealed bearing and see how it goes. As I only do 4 race weekends a year now I will check it at the end of the season.

Peter, I made a tool to pull the spring posts through the pressure plate so the circlip can be removed safely :-). I copied the drawing from this site that, I think, Brian posted but cannot find it on here now but have attached my copy. The problem I found was the thread in the posts is not very deep and also the 1BA screws from the adjuster plate are not long enough to reach when using the tool so I turned down a longer bolt and borrowed a 1BA die to rethread this. Had to make up a lever from flat stock to pull the post through the pressure plate when refitting the clips although a 1BA nut above the tool would work if I could have found one.

[46T Sprocket]

Sounds like a good idea, but, I find the Griffon clutch far too heavy and as my ISDT bike does not produce Griffon power do not see it needs to be- anyone know of a source of lighter springs? Is there a drawing of the correct spring compressor, my home made one is a bit of a bodge?

I've found that the Amal type levers need less force to pull in than the traditional steel doherty type. I've only ever used that type so can't comment on other makes.The fulcrum point is better placed than on the steel type and that gives the lever a bit more of an advantage.

Dave Higgins had a thread on here about modifying the lever in the griffon gearbox that might help you too. https://www.greeves-riders.org.uk/fo...griffon+clutch Here is another option to lighten the pull that has been discussed. https://www.greeves-riders.org.uk/fo...utch+lightener