Author Topic: Crankshaft shimming  (Read 1673 times)

Offline chaterlea25

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Re: Crankshaft shimming
« Reply #30 on: 13.06. 2018 21:43 »
Hi All
Quote
I know what you mean,but the prices for these are quite reasonable from other trusted suppliers at around £30 but no stock. I had exactly the same problem years ago when I needed -20. A lot of the new shells are unbranded as well so some risk there.

Following on from my reply to GB about the quality of parts
Big end shells are something where quality branded parts are essential

If a maker will not put their name on the packaging its not worth  buying

John
1961 Super Rocket
1963 RGS (ongoing)

Offline BSA500

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Re: Crankshaft shimming
« Reply #31 on: 16.06. 2018 15:30 »
Got the crank back from grinding looks good

Offline BSA500

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Re: Crankshaft shimming
« Reply #32 on: 22.06. 2018 12:51 »
Okay took two days but I have the crank shimmed at 1 thou. Tightening the sleeve against the bearing did the trick. I had bolted it up and the crank locked, did up the sleeve and voila 1 thou. There was alot more to it than that but yay it is done and the reground crank is spot on as well  *smile*

Online berger

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Re: Crankshaft shimming
« Reply #33 on: 28.06. 2018 12:37 »
i have not been to the pub, but will be because I can ;) well what can I say, my clunk now seems to have been the miss matched engine sprocket and sleeve. even tho they both could ride with each other they were not a good match. since ragging the crank about when changing the box and getting nothing more than the one and a half { mines a pint} thou it was set at it doesn't clunk anymore after fitting really good matching sprocket and sleeve. result! i'm going to have a gallon and celebrate BSA making several different set ups of these parts for owners to get confused with when other people have messed over the years *beer* KERLUNK!!!!

Offline Wayno

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Re: Crankshaft shimming
« Reply #34 on: 04.07. 2018 19:50 »
Hi Muskrat, I need to gate crash this discussion as I will be doing this job very soon.
I’ve read your instructions to check/set the crankshaft end float several times with great interest as I’ve never had this explained to me before.
I just about understand it (you’ll be pleased to hear) but I can’t quite work out where the end-float actually is!!
Are we adjusting the end-float of the main bearing?  I ask this as I think when we assemble the crank inside the casings and tightening the cush-drive nut up fully, it will put a side load on the bearing and take up any free play.  This will presumably pull the crank shaft away from the timing side bush and tight into the main bearing.
I have included a couple of photo’s showing both sides of my LH casing, the bearing outer race still fitted and with the large bearing shim (67-349) in place and free to rotate.
Presumably when everything is tightened up the large bearing shim (67-349) is trapped tight between the inner race of the bearing on the inside and the boss of the cush drive bearing (67-2053) on the outside and rotates in the LH casing with the crankshaft?
I hope you can resolve my confusion on this.
 

Online Greybeard

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Re: Crankshaft shimming
« Reply #35 on: 04.07. 2018 20:12 »
The arrangement locks the crankshaft to the drive side main bearing inner race so any expansion or float will be in the timing side bush. As the timing side bush supplies oil to the crank it needs to be pretty closely fitted, hence the crankshaft should have minimal endfloat. I believe this to be true but am willing to be told different.

Offline muskrat

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Re: Crankshaft shimming
« Reply #36 on: 04.07. 2018 20:53 »
G'day Wayno.
With the inner race on the crank and all the cush/drive components done up it can slide back and forth in the outer race (the rollers are only trapped by the outer race on the outside). So once you put the other case on there is movement between the thrust face of the bush and the rollers against the lip in the outer race. Shimming between the inner race and the crank reduces this movement. Do NOT shim between the outer race and case as there is no mechanical clamping them in place other than the interference fit of the outer race in the case.
See clear as mud!
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline Wayno

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Re: Crankshaft shimming
« Reply #37 on: 05.07. 2018 09:31 »
I woke up with one of those EUREKA moments.  Of course, when its all nipped up the only free play can be between the crank and the bush. DOH!!
I knew where I had to get just couldn't visualise it.  Must be all the sweat running in my eyes. 
My old bearing must be similar to yours as I can pop the rollers out and get at the inner race to use a puller.  The nice new bearing I received from DRAGANFLY yesterday (make QCB) looks great but can't pop the rollers out so cant separate inner race to remove it to add shims.  I fear once its on - its ON!!  I will have to return it. Do you know the make of bearings that you can pop the rollers out?
Very last question - is the crank end float 0.001" on all A7/A10 twins do you know?

Thanks for the help.

Offline muskrat

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Re: Crankshaft shimming
« Reply #38 on: 05.07. 2018 10:09 »
G'day Wayno.
If your real careful a bearing separator type puller can work on the rollers. Set it all up and add a little pressure then pour boiling water over the bearing.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online Greybeard

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Re: Crankshaft shimming
« Reply #39 on: 05.07. 2018 10:13 »
The arrangement locks the crankshaft to the drive side main bearing inner race so any expansion or float will be in the timing side bush. As the timing side bush supplies oil to the crank it needs to be pretty closely fitted, hence the crankshaft should have minimal endfloat. I believe this to be true but am willing to be told different.

G'day Wayno.
With the inner race on the crank and all the cush/drive components done up it can slide back and forth in the outer race (the rollers are only trapped by the outer race on the outside). So once you put the other case on there is movement between the thrust face of the bush and the rollers against the lip in the outer race. Shimming between the inner race and the crank reduces this movement. Do NOT shim between the outer race and case as there is no mechanical clamping them in place other than the interference fit of the outer race in the case.
See clear as mud!
Cheers


See, I talk a load of bollocks sometimes! I forgot that the drive side bearing has rollers. Lucky someone here knows what they are on about!

Offline duTch

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Re: Crankshaft shimming
« Reply #40 on: 05.07. 2018 10:20 »

 I'm a slower typerator than Musko and BG...they both got in on me..

 Posted by: Wayno
 
Quote
"....Of course, when its all nipped up the only free play can be between the crank and the bush. DOH!...."

 On that side, but on the other side.....the rollers against the lip, as ;

  Posted by: muskrat;
 
Quote
"....So once you put the other case on there is movement between the thrust face of the bush and the rollers against the lip in the outer race....."



 Wayno, what engine is yours ?

  I'm asking because that bit that shows in the picture looks like a Plunger engine part that I think later engines don't use- I had one in mine when I first bought it and always thought it was a oil-slinger type thing because the early Plungers to '54 had no seal, but I put one in (with LJ crank) and the 'Slinger' is now lost in history....


Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline Wayno

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Re: Crankshaft shimming
« Reply #41 on: 05.07. 2018 10:40 »
Dutch,
She is a plunger a very early short stroke A7.  Built Sep 1950 (before I was even a glint) Eng. No. ZA7-603.

I would guess it is an oil slinger too as it is clamped between the inner race of the bearing and the boss of the cush drive.
Guess it now spins at crankshaft speed and flings!!  Would this be to stop engine oil sneaking into the chain case?

Offline duTch

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Re: Crankshaft shimming
« Reply #42 on: 05.07. 2018 11:45 »

 
Quote
..... Would this be to stop engine oil sneaking into the chain case?......

 Yup- that's fairly much the way I see it...

 Mine is a BA10 with stamps 23.12.52, so Ive always called it a '52, and that's how it's rego'd, but now I know it's a '53 engine in I reckon a ~'56 frame
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline muskrat

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Re: Crankshaft shimming
« Reply #43 on: 05.07. 2018 20:53 »
G'day Wayno.
ZA7 AFAIK was the last of the long strokes. My A7 plunger is AA7 and the 53rd one off the line.  *dunno*
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline chaterlea25

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Re: Crankshaft shimming
« Reply #44 on: 05.07. 2018 21:08 »
Hi All

Googling QCB bearings as I had never heard of the brand brings me to,

https://nbcgroup.co.uk/products/bearings/cylindrical-roller-bearings

I wonder   *conf2   **????* *????* *????* *????*

John

1961 Super Rocket
1963 RGS (ongoing)