The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: anjimehra on 21.09. 2016 18:05
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Hi
Had to pick up a used old gearbox she'll as the one on my bike had been patched up with araldite. Upon assembling the g/box today, the inner cover would not seat on the case. Iam assuming the blind bush on the layshaft has been replaced with a locally made one with a thicker boss, or the thrust washer is too thick. Would be obliged if any of you guys could send me the thickness of the boss, & the thickness of the thrust washer
Thanks & ride safe
Anji
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Hi Anji,
put off the whasher and fit the sandwitch plate without the mainshaft.
Tighten the plate with the gasket. You can fill the space with bigger nuts.
With the gearbox fixed in a vice you can feel the play at the layshaft by pushing and pulling at the wormdrive from the speedo gear.
Every gearbox is different and had to shimmed out with a just visible play at the layshaft.
The shims had to be at the sandwitsh plate bush.
cheers Klaus
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Hi Anji,
put off the whasher and fit the sandwitch plate without the mainshaft.
Tighten the plate with the gasket. You can fill the space with bigger nuts.
With the gearbox fixed in a vice you can feel the play at the layshaft by pushing and pulling at the wormdrive from the speedo gear.
Every gearbox is different and had to shimmed out with a just visible play at the layshaft.
The shims had to be at the sandwitsh plate bush.
cheers Klaus
Hi Klaus
Thanks for the tip. Any idea what the size, number of the bearing on the main shaft in the sandwich cover is ? Thanks
Anji
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Hi Anji,
size is 3/4 x 1-7/8 x 9/16 insh
have a look at here, were I get mine, but he has a long deliver.
http://www.ebay.de/itm/131646170160?_trksid=p2060353.m2749.l2649&var=431038062293&ssPageName=STRK%3AMEBIDX%3AIT
cheers Klaus
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I've seen a figure for the flanges on both layshaft bushes, and 0.093" comes to mind but I think each end is different to each other.
It's there on the nets somewhere.
Otherwise run a straight-edge across the faces and measure the gap from the interface to the 1st gear before measuring from the interface on the inner cover (biscuit/sammidge *conf* plate) to the bush flange.
On the ones I have, from memory this is almost flush, but whatever- do the maths (all of) and you should work it out fairly easy. If the bush flange is too thick is in my opinion better than adding shims as the flange can be fettled to suit (shims can be messy)
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I've seen a figure for the flanges on both layshaft bushes, and 0.093" comes to mind but I think each end is different to each other.
It's there on the nets somewhere.
Otherwise run a straight-edge across the faces and measure the gap from the interface to the 1st gear before measuring from the interface on the inner cover (biscuit/sammidge *conf* plate) to the bush flange.
On the ones I have, from memory this is almost flush, but whatever- do the maths (all of) and you should work it out fairly easy. If the bush flange is too thick is in my opinion better than adding shims as the flange can be fettled to suit (shims can be messy)
Thanks dutch. Will keep you posted on developments. Currently trying to find the manufacturers number code on the main shaft ball bearing at the foot shift end. Was given a eBay site by Klaus, but logistically very difficult to import to India. Will have to get a local make but need a number to cross check
Anji
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Hi Anji,
Currently trying to find the manufacturers number code on the main shaft ball bearing at the foot shift end
The bearing is known as RLS6 or LJ 3/4
John
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Hi Anji,
Currently trying to find the manufacturers number code on the main shaft ball bearing at the foot shift end
The bearing is known as RLS6 or LJ 3/4
John
Thanks John. Came across RLS 7 last night when looking for it on the net, against the original Hoffman Ls7 . Am a little confused. Any advice ?
Anji
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Hi Anji,
Confusing ?? YES *eek*
Have a look at this web page which should help
http://simplybearings.co.uk/shop/Bearings-Deep-Groove-Ball-Bearings/c3_11/index.html
John
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Hi Anji,
Confusing ?? YES *eek*
Have a look at this web page which should help
http://simplybearings.co.uk/shop/Bearings-Deep-Groove-Ball-Bearings/c3_11/index.html
John
Thanks John. LJ 3/4 it is, but difficult to find here in India. Everything long converted to Metric sizes. Starting the hunt !!!
Anji
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Hi Anji,
size is 3/4 x 1-7/8 x 9/16 insh
have a look at here, were I get mine, but he has a long deliver.
http://www.ebay.de/itm/131646170160?_trksid=p2060353.m2749.l2649&var=431038062293&ssPageName=STRK%3AMEBIDX%3AIT
cheers Klaus
Thanks Klaus. Just not able to lay my hands on a english size bearing here. Search continues
Anji
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Hi Anji,
Currently trying to find the manufacturers number code on the main shaft ball bearing at the foot shift end
The bearing is known as RLS6 or LJ 3/4
John
Hi John
Went to the SKF dealer who insisted that LS 8 is the equivalent to the RLS 6. Even showed me the cataloguie which said the same. Bought the bearing, only to find it dosent go over the shaft. Measured the bore with a vernier & found it .002 less than 3/4. The dealer swears its an exact match for RLS 6 ????
Anji
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Hi Anji,
Bugger *ex* *ex* *ex*
Measure the other dimensions and see if they are correct ?
2 thou under 3/4in = 19mm exactly ???
Bring the shaft and bearing back to the dealer and get him to check his stock to see if you just got a bum bearing
2 thou is too tight a fit for even pressing on, it should be a push fit by hand.
When Klaus was here in Ireland and had gearbox problems, the bearing fitted to his gearbox was a tight fit on the mainshaft
I have not found this issue before??
John
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Anji,
For me, measuring IDs with a caliper is always iffy. Is it possible that the ID could be as little as 0.0005" under (within tolerance spec perhaps) and it just needs to be heated and slipped over a chilled shaft? If you have a friendly tool and die shop, maybe they can give you a closer measurement. I'll be interested to hear what John says (or others) about my thought here.
Richard L.
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Anji,
For me, measuring IDs with a caliper is always iffy. Is it possible that the ID could be as little as 0.0005" under (within tolerance spec perhaps) and it just needs to be heated and slipped over a chilled shaft? If you have a friendly tool and die shop, maybe they can give you a closer measurement. I'll be interested to hear what John says (or others) about my thought here.
Richard L.
Hi Richard
I used a dial gauge vernier which is pretty accurate. The id is exactly 19.0 mm on the LS 8. The shaft OD measures 19.05
In my experience the bearing should should fit easily on to the main shaft with min pressure, else it will be impossible to open the outer cover once installed & you, say, need to change the kick spring.
Trying to locate a RLS 6 or a LJ 3/4 . Work held up for 2 weeks in the hunt for a brg.!!!
Anji
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If buying one here and shipping to you would somehow help, let me know.
Richard L.
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Hi All,
Anji,
If all else is ok with the bearing size then it maybe possible to hone the bearing bore to size ??
Richard
I was trusting Anji's measurements, as I posted earlier, 2 thou is too tight
John
PS,
Bearings are a sore subject this week *sad2*
The spindle bearings on my milling machine had developed a little play, 0.0015in. or so
they of course are "specials", high precision angular contact type, matched as a pair
Trade price including tax just over €400 *eek* *eek* *eek*
Once ordered they took almost 10 days to arrive, I asked at the bearing shop about the special grease needed and was told they come pre packed
No they weren't *problem* so start looking for the Kluber NBU15, and then order that, so another wait until that arrives *pull hair out*
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Hi Anji, I've spun a used crankshaft main bearing o.d. in a lathe and applied emery cloth to the I.d. In order to make a easy to trial bearing to get the crankshaft end float correct, so I guess the same could be done with your gearbox bearing? albeit you have a bit more metal to remove....., I did not have too much trouble with I.d spinning, surprisingly.
It's a surprise you have to fettle a standard bearing to get it to fit, but having to fettle parts in order to get them to fit is rather too common *work*
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If buying one here and shipping to you would somehow help, let me know.
Richard L.
Hi Richard
Did you get my message sent a few days back?
Anji