The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: PatM20 on 29.03. 2018 14:47
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I was going to replace these two bushes as there seems to be a little play coming from that end; the main bearing seems fine.
My reading up on this topic suggests that for my bike I need two of the long bushes i.e. 67-3080 as opposed to one long and one short (short being 67-3073).
I don't remember losing any oil from this area and don't remember having any issues with the gearbox, so was wondering if I am getting a bit picky in my old age.
Can anyone advise me as to the amount of play that is acceptable? Is it a case of "if you can feel play, then sort it!"?
Regards
Pat
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the bushes in mine are both 3073 but one drilled, ive just found a sleeve gear that had been bushed and i reemed them to fit a shaft that was half a thou more worn on the clutch end, very fiddly. I would say ive seen shafts and bushes that are sloppy and leak a bit of oil when on the side stand ,if theres only a little play I would leave them because to do a proper picky job the shaft needs grinding and bushes made to fit[expensive] if your unsure about the play ask a mate or mechanic, I can say no more apart from not many people bother with this for the miles they do :!
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Can anyone advise me as to the amount of play that is acceptable? Is it a case of "if you can feel play, then sort it!"?
I know nothing about gearboxes, so I cannot advise you on how much or how little play is acceptable. However, if you go looking for trouble you will undoubtedly find it! What I can tell you from my own experience is this: My gearbox used to leak oil after being on the side stand for a few days. I replaced the oil seal, and while I was at it I also fitted one of SRM's gearbox sprocket nuts that incorporates an oil seal and it hasn't leaked since.
John
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I was going to replace these two bushes as there seems to be a little play coming from that end; the main bearing seems fine.
My reading up on this topic suggests that for my bike I need two of the long bushes i.e. 67-3080 as opposed to one long and one short (short being 67-3073).
I don't remember losing any oil from this area and don't remember having any issues with the gearbox, so was wondering if I am getting a bit picky in my old age.
Can anyone advise me as to the amount of play that is acceptable? Is it a case of "if you can feel play, then sort it!"?
Regards
Pat
I’ve replaced sleeve gear bushes. Twice *problem* as I suspect I was supplied duff bushes the first time, that quickly failed. I posted up details a few years ago.
I honed mine to size using a cheap brake cylinder expanding hone, on a drill.
You need some clearance say 001, otherwise they will seize. 010 is too much clearance for sure, So I’d guess 005 is a reasonable limit?
I don’t worry about small oil leaks like would come from the box, and only have a centre stand anyway so it would not leak much.
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hello pat you say you may be getting picky in your old age well ime getting less picky, in the seventies if I stripped an engine I allways replaced ball races, this happened very often as I knocked out many tiger cub big ends.these races had thousands of miles left in them and so did the rings I replaced, at the moment ime building up two gearboxes, one to replace what ive been running in the beezer for years because ive found glitter in the oil which might be because of using oil that attacks brass. if I hadn't have found that sleeve gear with new bushes I would have been putting a used one in, the cases ime using will be getting new ball races because theve been stood in garages for years in muck but they will not be getting new bushes as these boxes ive got have been on the floor longer than theve been in a bike even though I can shake the layshaft about in the blind bush, years ago this would have been out and a new one fitted and it would probably have the same amount of shake when wobbling the shaft about. ime also putting an rrt2 together for another project, 35 or so years ago the Torrington races would have been out and new ones fitted but I know this would be money wasted as the same applies to this box being stood for years. the good advice has been mentioned about not having more than about 5 thou of play. so you may be getting picky but I think ime learning not to throw money away. about time too! *smiley4*
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Thanks for all your thoughts. I think I will leave the bushes alone.
I have an adjustable reamer somewhere to fit, but I don't own accurate enough measuring tools to get down to 1 thou type tolerances.
Regards
Pat
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People keep forgetting they were made in the 50's & 60's.
I have just done the box in the M20.
No bush left there at all.
Apart from the inability to select 1st from stationary and the odd slip out of top back to 3rd no great problems.
And it has been like that for a long time, I just never got around to doing the box.
Ridden thousands of miles with the knackered bush.
A bit more of a problem if you have a 6 spring clutch where the basket actually is free to move when the clutch is pulled in as you can get enough wobble to throw the primary chain if you back off then change down using the clutch.
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bit off topic but these old bikes don't give up, I was riding mine about in seventies with a flat[worn out] camshaft super pocketed valves concave cam followers ,timing retarded to the point of only getting a quarter throttle and eventually a snapped crank,..... still running. I only found out its crank had let go on the timing side coming back from silverston races to chesterfield and as soon as I got home I decided to strip it working till gone midnight as you do when your young I pulled the drive side case off and the crank fell out leaving the timing side web still in place. needless to say the whole engine was shot. I saw one advertised complete with competition mag, dynamo, carb all still in the engine plates with gearbox. the guy who was selling it had put the grinder through his frame to fit a watercooled suzi engine and make what he called a kneeler.all that I got only cost 100 pound I still think it was a bargain
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Yes exactly right, they are low tech working mans vehicles.
I rode my A 10 from Jamberoo ( before it was a fun park ) back to Sans Souci about 90 miles, with the left rod jambed into the crank by a lump of piston skirt.
So it did the distance on one cylinder with the other one smashing up the cylinder skirt and eventually lifting the entire block off the cases after it had run a crack all the way round the flange, but it was still running. and it got me home ( well to within a easy push of home any way).
I turned it off going down the Captain Cook bridge because the exhaust pipes were flailing around and banging into the back wheel which made it near impossible to ride in heavy traffic.
people forget they are not 2006 water cooled bikes made from parts machined to withing a 0.0001" tollerance and whisper quiet.
I could name at least 50 people who spend 50 hours in the shed for every 1 they spend on the road chasing down silly little things that we would have ignored in the day.
If it goes you rode it till it didn't then you fixed it and those were the day before mobile phones so when it stopped it was a long push home
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Bit off topic butt related -
Yep quite surprising what an engine will do, in the sixties the farm bought six Massey Ferguson 65s, three came from Kilmarnock and three from Coventry, all three Killie ones broke there crankshafts between the first and second cylinders, mine went while chopping silage, a pretty heavy pull, I new it had lost a bit of oomph, but it still went on doing the job, our mechanics had heard of the fault and guessed correctly what was up, new crank and it was fine again, obviously a bad batch of cranks