classic motorcycle forum
Motorcycle Discussions => British Bikes => Topic started by: Vreagh on April 26, 2021, 07:44:02 PM
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Hi, I'm progressing well with a FB black hawk but am puzzled by the clutch. It was a ball of rust but has dismantled fairly well until I came to remove the drive plate. Presumably it's the usual Albion large ball race but there's no large circlip or provision for one. The clutch is locked solid but the plates can be "sprung" a little apart. I imagine the large bearing is seized. I've left the clutch on the mainshaft to enable a bit of leverage. I cannot find an exploded view but am wondering if it necessary to gain access by the rear. I'd be greatful for any information.
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What year is your Blackhawk again ?
I can't quite remember any complexities in those clutches, and can't even find a decent pic of one dismantled.
This doesn't quite cover it either ...
http://www.tractorbox.co.uk/forum/forum_posts.asp?TID=6029
Maybe this will jog someones memory ?
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Thanks for that, it's more than I've been able to find. It's not identical to mine but it gives a clue to its contruction (mine is a single driven plate. Not sure on the date of the Black Hawk 1929 - 1934 were the production years but mine could be an assembly of parts. The 196cc barrel is marked Super Sports but the piston is cast iron not alloy.
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Usually the clutch on lightweight Albion boxes just pulls apart from the front. Never seen one otherwise. Idiot simple. As yours is a ball of rust it sounds like you just have a corrosion problem preventing dismantling. Nothing that copious amounts of the de rusting fluid of your choice plus a small wire brush won't overcome. Just relax and take your time and all will be revealed.
I'm more curious about your engine. You appear to have a combination of 1E and Super Sport parts. Nothing wrong with that as they will happily play together but some combinations play much better than others. The 1E and Super Sport pistons have identical dimensions and exchange effortlessly. The problem is the 1E jobbie is cast iron and the Super Sport alloy. The 1E piston is HEAVY, so much so it is used in the Upper Congo to stun elephants. The Super Sport piston is 1/3 the weight and makes for a much sweeter engine. What engine do you actually have in the beastie? What is the engine number?
Cheers,
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Pics of all the Albion clutches from one plate to multiplate in Newnes Motor Repair series books ,as well as the gearboxes.....Id put them up,but my scanner doesnt work.
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Hi, the engine no is KZB 179. The piston is definitely cast iron, let's hope they changed the crank as well or I might have to re-balance with lead. Clutch is free at the friction surfaces but is seized at the bearing. Difficult to get at without putting undue side loading on the plates. Can't use heat without firing the corks which are in good condition. As suggested, I'll try WD and patience now I can see the contruction. Many thanks for the info.
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Don’t kid yourself. If you look in a Villiers parts list of the time you will see they used exactly the same crankshaft and con rod for both the Super Sport and 1E. If they didn’t worry about balance you needn’t either.
Interestingly, Villiers made both Super Sport and 1E pistons using the same mould. It’s not just that the pistons share the same basic dimensions but are made slightly different due to the qualities of the two materials. They are identical. I once had N.O.S Villiers factory examples of both so could compare and examine both closely. Obviously 80 some years ago Mr Villiers didn’t worry so much about these things as we do today.
Personally I’d replace the piston with the right alloy version. The KZB prefix shows the engine is a Super Sport and it will be much more lively with the right alloy piston. They’re easy enough to find.
Finally, you might be reluctant to use heat on the clutch but you can use one of those freezing sprays. It will have the same effect.
I look forward to the next instalment.
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I wouldn't use WD40 for releasing anything rusty. Plus Gas (or a more modern equivalent) is far better.
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The ball race in the sprocket is a tin cage holding loose balls......I imagine if its rusty enough to jam the whole lot together ,the balls and races have had it anyway,so busting the tin shields apart wont cause any further damage.......Everything else is solid steel......Its possible that a Royal Enfield supplier may have the bearing unit,also possible its the same size as the Indian 350 of say 30 years ago,or even more recent.
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I’d be surprised if Villiers Services can’t supply both sprocket and clutch centre off the shelf.
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I've never received an answer for any of my part queries to Villiers Spares.
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Apparently in these Covid times you have to ring them.
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I don't think that's so. I emailed them some weeks back to ask them what the turn-around was on some brake shoe relining, and the reply came back in an hour or so. The shoes took a little longer at a week.. ;)
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Well the clutch is finally apart without any damage to the plates. As John.K said bearing races were pitted, but the steel cage was undamaged. As an experiment ( and I'm a tight bug**r), I've made a single piece split bearing out of Teflon that fits inside the cage. I lightly ground the races smooth but left the pitting and scraped the Teflon untill the spocket spun freely. It may or may not work in practice, but I've burnt no bridges and it's easy to return to original. One question though, I've always understood that cork clutches need oil to provide cooling but this clutch is in the air, so how does that work?
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The oil is normally there for the benefit of the primary chain. The clutch corks don't need oil, and in fact some bikes (plunger A series BSAs for one) have a clutch entirely separated from any primary case oil.
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Seeing that many manufacturers went to great pains to keep their clutches dry and other ran them in oil anyway I suspect it really doesn’t matter whether oily or not. Excessive slipping is a no-no. The cork chars and burns. Doesn’t take overheating at all well.
Albion ran a bronze ring on the clutch centre until the mid 20’s when they finally changed to balls. As long as there are no badly corroded areas that can tear the Teflon ring there’s no reason why it can’t outlast the old bronze ring style. I’ll be interested to see how it goes. It’s a modern take on a vintage practice.
Cheers,
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Don't forget that the only time the bearing does any work is when the engine is running and the gearbox mainshaft is not rotating e.g. stopped, in gear, with the clutch lever pulled in. Avoid these situations - slip it into neutral before you stop, paddle off a bit before you drop it into gear - and the teflon will probably last "forever".
Leon
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Albion actually returned to the bronze ring bearing for Royal Enfield in the sixties. About 1963 they revised the clutch centres for the 250/350 Crusader range and also the 750 Interceptors fitting the bronze (not sure exactly what material,) ring to a new and slightly larger clutch centre. Bullets of the semi- or pre-unit variety had ceased production by then so never got this modification.
REgards, Mark