The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: Slymo on 05.01. 2021 02:25
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I’ve obtained a tidier sleeve gear for my STD SR gear box. I’m planning to polish the mainshaft with a stone and then re bush and match the ID of the new bush to the resurfaced shaft. I got a new bush with a 15/16” OD as per the book and from previous experience but on removing the old bush I discover the resultant hole is 29/32”. This is a surprise and I wonder if anyone has found this before?
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I’ve obtained a tidier sleeve gear for my STD SR gear box. I’m planning to polish the mainshaft with a stone and then re bush and match the ID of the new bush to the resurfaced shaft. I got a new bush with a 15/16” OD as per the book and from previous experience but on removing the old bush I discover the resultant hole is 29/32”. This is a surprise and I wonder if anyone has found this before?
Plenty of general info here https://www.a7a10.net/forum/index.php?topic=5202.0
I guess you are asking if your gear is modified or off another bike? Is it the same as the less tidy one?
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Hi thanks for responding. I read that thread through but no mention of the bush OD only the size of the ID and main shaft. This sleeve gear looks absolutely identical to the others I have in my collection except that the bore without the bush rather than being 15/16ths (0.9375") is 29/32nds (0.90625") I can turn the bush down easily enough as I have plenty of wall thickness having got it with 7/8" ID in order to bore it to a nice close tolerance. What interests me is the wierdness of it as this sleeve appears to be a standard in everything from B31s onward.
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Could it be a timken bearing type sleeve gear? (I have no idea what those are like, but the needle roller boxes do have slightly different parts).
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No whilst that would make sense it had a steel/bronze bush in it. Just a 32nd” smaller than the usual. Must have been a rouge week at the works. New bush turned down to fit now.
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Hi Slump,
Do not forget to put a relief in the middle of the bush where the gap was between the 2 old bushes, it holds a drop of oil
I had a one piece bush sieze without the relief,
The bore in the needle roller sleeve gear is stepped so it's not that
John
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Yes cheers I've machined a relief in the Centre of the Bush, what I hadn't done that could have courted serious disaster was tighten the grub screw for the selector rod. I was riding back from visiting my very elderly mum and had a sudden and disturbing realization that the rod was basically floating. Got home to discover that it was poking out of the box just shy of clipping the final drive sprocket. In order not to have to pull the whole primary side off again I lay underneath the bike with a 1/4" drive rachel with a 1/4" socket with a screw driver bit inserted that I turned by clicks with a 1/4" spanner having pushed the rod back home into the box with a big screw driver against the final drive sprocket. Just when I begin to think I'm a competent mechanic 😨
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unless you have owned both the bike & the sleeve gear from new there is no reason whatsoever to assume the gear has not been machined at some time in it's life.