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Re: A65 crankshaft end float [Re: Mr Mike] #491984
05/28/13 1:27 am
05/28/13 1:27 am
Joined: Jul 2009
Posts: 3,549
Vic. Australia
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Pete R - R.I.P. Offline
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Vic. Australia
You should have somewhere between 0.0015" and 0.003" interference at room temperature,say 20C.

Aluminiuum expands roughly twice as much as steel.
The difference is about 0.001" per inch diameter for 100 C. temperature rise.With 50 degree rise on 2-13/16 diameter bearing,you lose 0.0014" of your interference fit.Crankcases can,and do occassionally,reach 100 C.

Even if you had 0.002" inteference at room temperature,you could have less than no interference when the engine is hot.

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Re: A65 crankshaft end float [Re: jamie weeks] #491986
05/28/13 2:16 am
05/28/13 2:16 am
Joined: Aug 2001
Posts: 3,884
Cape Carteret, NC
M
Mr Mike Offline
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Cape Carteret, NC
Pete,
If you are correct these bearings would not stay in the case very long but most do. I for one would have like to see an additional retainer of some sort but the BSA system seems to have worked but requires very accurate machining to hold tolerance for an interference fit. HOWEVER, once that outer race move relative to the case, the case is junk.

Mr Mike

Re: A65 crankshaft end float [Re: Mr Mike] #491989
05/28/13 2:33 am
05/28/13 2:33 am
Joined: Jul 2009
Posts: 3,549
Vic. Australia
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Pete R - R.I.P. Offline
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Vic. Australia
Originally Posted by Mr Mike
HOWEVER, once that outer race move relative to the case, the case is junk.

They always move when the engine gets hot.There was some discussion about this on the Norton Bulletin Board,a little over a year ago. Bearing Movement in Crankcase

Re: A65 crankshaft end float [Re: jamie weeks] #492057
05/28/13 6:18 pm
05/28/13 6:18 pm
Joined: Oct 2008
Posts: 5,287
Gnashville
DavidP Offline

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Gnashville
From that Norton post:
"Just to re-confirm what I had found in the past I pulled an old virgin 750 bottom end off the shelf and checked the end play. It had a tight .002 IN.- about right for a ball bearing.
I stuck it in the oven at 220 F. for one hour.
The end play was then .034 and I could move it back and forth by hand."

I assume that this increase also happens to our BSA engines once they get up to temp?


Stepping on others doesn't make you stand tall.

71 A65L "Zelda"
92 BMW K100rs "Gustav"
72 T120V cafe project "Mr. Jim"
72 T150V "Wotan"
Re: A65 crankshaft end float [Re: jamie weeks] #492127
05/29/13 3:54 am
05/29/13 3:54 am
Joined: Aug 2001
Posts: 3,884
Cape Carteret, NC
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Mr Mike Offline
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Cape Carteret, NC
David,
I suspected the same thing and measured endplay on a roller motor. I then heated the whole assembled bottom end up in an oven. The endplay increased measurably with a dial indicator. Coefficient of expanison of Alum is approximately 2x that of steel. Based on that I would set the endplay at the bottom end of the limit, but, I have often wondered what gets hotter under normal operation the crank or the cases
Mr Mike

Re: A65 crankshaft end float [Re: jamie weeks] #492136
05/29/13 6:32 am
05/29/13 6:32 am
Joined: Mar 2011
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derby england
wak Offline
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derby england
im not sure im buying this, when you run the bike its air and oil cooled,i cant see the cases getting much hotter than the oil, and if its growing that much whats happening at the cylinder base,timing gears ,primary chain? not to mention piston and rod alighnment.if it expanded that much every time it cooled all the bolts would be loose.


BSA lightning
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Re: A65 crankshaft end float [Re: jamie weeks] #492164
05/29/13 1:24 pm
05/29/13 1:24 pm
Joined: May 2013
Posts: 5,142
Rotherham - S. Yorkshire
Allan Gill Offline

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Rotherham - S. Yorkshire
My bike was running 018" of end float when cold, never checked it hot. The crank was perfectly fine when it was pulled apart. It probly didn't do the primary chain too many favours but if anything it probably worked in harmony with the wobble in the clutch basket laughing

I'm with wak though. If you just heat the whole engine then yes the cases will expand a bit, not at any great expanse though otherwise the cases would crack at its mounting points. When your running the motor, the moving components generating heat are made of steel, the oil flow is removing heat, some is transferring to the cases which is being cooled by air flow. The overall rate of expansion is probably fairly even. Run the engine for 20 miles and check it then!

I think as long as you have enough clearence so nothing nips up tight and not too much so that the engine throws its self apart there is little to worry about.


beerchug
Re: A65 crankshaft end float [Re: jamie weeks] #713676
11/03/17 1:04 am
11/03/17 1:04 am
Joined: Jul 2006
Posts: 481
just a guy from Jersey [Hopewe...
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nert Offline
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just a guy from Jersey [Hopewe...
So, on a 1966 A65 roller type bearing, the crankshaft can still float with the spacer, gear, and rotor all tightened up? It doesn't feel like it. Or should I measure end float with out the spacer, gear, and rotor torqued up.?


keep your "oddies" lubricated, and carry a dime
Re: A65 crankshaft end float [Re: nert] #713705
11/03/17 12:12 pm
11/03/17 12:12 pm
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Posts: 504
new jersey usa
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pushrod tom Offline
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new jersey usa
Everything needs to be torqued up. A pain but necessary. PRT

Re: A65 crankshaft end float [Re: jamie weeks] #717050
11/29/17 12:58 am
11/29/17 12:58 am
Joined: Aug 2017
Posts: 3
Toronto Ontario Canada
6
69BSATONY Offline
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Toronto Ontario Canada
I'm learning as i go along.
Since the cases have to be assembled and pulled apart a few times to get the end float right
how do you guys install and remove the roller bearing without busting it. mine is very tight on the shaft.
I all ready ruined one and waiting for a replacement . At $ 100 bucks ???
Should I sand the shaft or the inner race ?
Thanks



69 BSA lightning

Re: A65 crankshaft end float [Re: 69BSATONY] #717054
11/29/17 2:43 am
11/29/17 2:43 am
Joined: Aug 2001
Posts: 4,600
Owego, NY, USA
Mark Z Offline
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Owego, NY, USA
Originally Posted by nert
So, on a 1966 A65 roller type bearing, the crankshaft can still float with the spacer, gear, and rotor all tightened up? It doesn't feel like it. Or should I measure end float with out the spacer, gear, and rotor torqued up.?


The rotor nut pulls the crank tight to the inner race of the roller bearing. With a roller bearing however, the inner race can "float" with respect to the outer race.

Not sure what you mean by "it doesn't feel like it" - I doubt you could detect 2 thou of movement without a dial indicator. Also, are you trying to check this on a fully assembled motor? It should be checked with the rotor nut torqued down, but without the crank pinion and oil pump installed.

Originally Posted by 69BSATONY
I'm learning as i go along.
Since the cases have to be assembled and pulled apart a few times to get the end float right
how do you guys install and remove the roller bearing without busting it. mine is very tight on the shaft.
I all ready ruined one and waiting for a replacement . At $ 100 bucks ???
Should I sand the shaft or the inner race ?
Thanks
69 BSA lightning


Wow, if you ruined a bearing (just the inner race, right?) getting it off, it was really on there! They're usually not THAT tight. Yes, I would do a bit of sanding, on the crank. Fine emery, go slow, wipe it clean and apply a bit of oil before test-fitting.



Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: A65 crankshaft end float [Re: jamie weeks] #717089
11/29/17 1:33 pm
11/29/17 1:33 pm
Joined: Aug 2017
Posts: 3
Toronto Ontario Canada
6
69BSATONY Offline
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Posts: 3
Toronto Ontario Canada
Thanks Mark z.
Will do that when I get the new bearing .

Re: A65 crankshaft end float [Re: jamie weeks] #717092
11/29/17 1:52 pm
11/29/17 1:52 pm
Joined: Aug 2001
Posts: 4,252
argyll. scotland, uk
gavin eisler Online content
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argyll. scotland, uk
To get the shims correct it helps if an old main bearing is used, remove some material from the bearing inner bore ( a small flapwheel will do it) and outer shell to make trial fitting easy, as long as the width is the same as the new one this allows trial fits with no drama. its best to have tight/ snug final fit. I have had to resleeve a DS mainshaft so I am wary of removing material from this part.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
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Re: A65 crankshaft end float [Re: jamie weeks] #717104
11/29/17 4:02 pm
11/29/17 4:02 pm
Joined: Jan 2004
Posts: 3,904
ca, us
D
DMadigan Offline
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ca, us
You need a bearing puller that clamps around the rollers with a lip behind. Something you would have if you did this more often.
If you use an old bearing as Gavin suggested you should measure the inner race width with a micrometer to be sure they are the same. Different manufacturers may have different tolerances.
I would not suggest doing anything with the crank to make removal easier. Since you do not have a bearing puller I doubt you have the equipment to do it properly.

Re: A65 crankshaft end float [Re: jamie weeks] #717151
11/29/17 9:01 pm
11/29/17 9:01 pm
Joined: Sep 2004
Posts: 900
Farnham, Surrey, UK
gunner Offline
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Farnham, Surrey, UK
IMHO its not unusual to find that bearings don't fit easily on to crankshafts or other shafts. Whether this is due to inaccuracies in BSA or bearing manufacturing is unknown to me, I guess you would need accurate measurement apparatus to find out where the problem lies.

Also, its not clear to me what the ideal clearance between a crankshaft and bearing internal diameter should be. I'm aware that C3 clearance is intended to take up bearing compression when fitted into a crankcase housing and also tight fitting onto crankshafts. However what if both conditions exist, does this mean a bearing with even larger clearance is needed?

Where a bearing is a very tight fit on a shaft, my preference is to hone the inside diameter of the bearing so that its a nice tight sliding fit on the shaft. Its better to remove material from the bearing as these are easier to replace compared to crankshafts.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: A65 crankshaft end float [Re: jamie weeks] #717158
11/29/17 10:31 pm
11/29/17 10:31 pm
Joined: Mar 2005
Posts: 10,251
Boston, Massachusetts
J
John Healy Offline
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Boston, Massachusetts
Quote
IMHO its not unusual to find that bearings don't fit easily on to crankshafts or other shafts.


They were designed that way!

Quote
Also, its not clear to me what the ideal clearance between a crankshaft and bearing internal diameter should be. I'm aware that C3 clearance is intended to take up bearing compression when fitted into a crankcase housing and also tight fitting onto crankshafts.


It is not either or.

It is if both are a press fit you use a C3. Of course it depends on the press fit. The shaft and bearing dimensions are plus or minus about .001".

The problem with having the bearing a slip fit is, if the rotor nut comes loose the harder bearing wears the crankshaft. It can wear the shaft enough that it will need plating to restore the fit. So, while you can make it a slip fit, it isn't such a good engineering practice.


Re: A65 crankshaft end float [Re: jamie weeks] #717163
11/29/17 11:47 pm
11/29/17 11:47 pm
Joined: Sep 2004
Posts: 900
Farnham, Surrey, UK
gunner Offline
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Thanks John, point well made and now understood.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: A65 crankshaft end float [Re: jamie weeks] #717170
11/30/17 1:00 am
11/30/17 1:00 am
Joined: Aug 2001
Posts: 4,600
Owego, NY, USA
Mark Z Offline
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Mark Z  Offline
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Owego, NY, USA
I will defer to the advice given above. Using an old bearing with some material removed to test fit is an excellent idea. Also using a bearing puller, and sanding the bearing rather than the crank if sanding is needed (although it's easier to evenly sand an outer surface than an inner surface).

I was always able to get the bearings off the cranks on my A65s with just a bit of prodding.




Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: A65 crankshaft end float [Re: jamie weeks] #718193
12/09/17 2:11 am
12/09/17 2:11 am
Joined: Aug 2017
Posts: 3
Toronto Ontario Canada
6
69BSATONY Offline
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Toronto Ontario Canada
Thanks for the advise.I do have one of those bearing pullers. This bike was sitting outside for 30 years and whoever worked on it last didn't shim the crank at all so the bearing was stuck against the crank side pretty good. Plus by the red ish color under the bearing they must have used locktite by the gallon.
I bought a bearing with shims and cup from CBS in California. Soon as it gets here I will compare widths . If they are the same I'll use the old one to set things up and use the new one on final assembly.

Thanks again

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