The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: Bart3 on 27.04. 2016 00:20
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I have a 1953 Golden Flash plunger. When I took it out for the first time the other day the clutch slipped in high gear. I ordered new springs and plates which will be here tomorrow. When I took the cover off the clutch, there was a small amount of oil on the plates. This is a six bolt clutch with a gasketed cover on the outside. There is no real seal in the inside but a series of interlocking washers that don't really seal. Most of the clutches I have dealt with in the past were wet. Is this one dry? When I put it back together should I oil the plates or not? Also I don't seem to find the proper adjustment specs for the cush drive in the manual. Thanks
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Hello, the 6 spring should tolerate a little oil, call it half'wet :O) Do the general adjustment (see http://www.a7a10.net/forum/index.php?board=17.0). If still not ok, check the plates condition (wear\warping) and spring condition. Fit the new ones if you think they look better.
Fine (very fine) adjustment of the 6 springs to get even lifting all around is well worth the time spent and can make all the difference. I got a very good clutch behavior after doing this.
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The clutch fitted to the plunger models is one of the best, if not the best, clutch BSA made. Adjusted properly and in reasonable condition it will operate perfectly.
Put the plates in dry but having said that they will tolerate some oil. Use quality friction plates, I only use Surflex personally.
As for the cush drive do the nut up tight, there are no "specs" for it. If the nut was loose its possible the cam lobes were going over which can give you the same effect as clutch slip although you should be able to hear it if that was happening.
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Ditto ^^. Once set up right it's a pleasure to use.
Cheers
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Thank you all for the advice. I will install the new springs and friction plates later today when they come in. Interestingly my inner drum has no Woodruff key but is splined. A bit of a trick getting all the rollers in place along with the chain but I finally got it with some help from a dab of grease. I will install the plates dry. I don't see how the oil will stay completely out of the clutch but it is good to know that some will be tolerated.
On to sorting the dynamo next.
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Hiya Bart, I've never used the clutch-basket cover, and haven't have any problems.
Initially left it off because I figured I'd need to be back in before too long *conf*.
Also, the last couple of times I've wound on the adjusting nuts an equal number of turns as a start point, and they were close to spot on- second last time had no noticeable run-out at all (~18 turns from engage).
To do that I used a socket with a ground end to make it flat, and made a mark on (rocket science *eek*) and counted (only lost count a couple of times), doing it diagonally a few turns (5?) at a time helps
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G'day Bart.
I use a dial gauge with a magnetic base to get the pressure plate to lift squarely. See below, I posted in another topic.
As duTch said they will work without the cover but I was worried the basket could spread without it as it doesn't have a band around it like other clutches. My starting point is when the base of the nuts are level with the pressure plate.
"Mount it to any steel part, barrels, tool box, footpeg. I use cable ties to secure it.
I use a cable tie to hold the clutch lever in (just enough to lift the pressure plate) against the hand grip and spin the clutch with the kick start lever. Adjust the springs then work the clutch lever a few times and check again."
Cheers
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After much research and several phone calls, I have found that the six-spring clutch with a gasketed cover needs to run dry. I replaced the springs and the plates. I got it to be good and parallel with a dial gauge fastened magnetically to the lower frame and then tied with a wire tie. I am waiting for a repaired dynamo to test it.