Author Topic: A10 crankshaft spline  (Read 1326 times)

Offline Slippery Sam

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A10 crankshaft spline
« on: 06.09. 2016 09:04 »
Hi,
I think I have a problem *sad2*
I'm busy building my A10 (D10R) and about to fit my shiney new Bob Newby clutch.
My problem is my crank has a wide (standard?) spline on the first inch out from the engine casing - then a narrower spline out to the thread.  Basically it's not the same spline all the way through.  I have an old knackered crank in my spares box and it has a uniform spline all the way through to the thread (and would be a great fit for the crank pulley).
As it is the crank pulley will only be a good fit on the first 1/2 inch of spline (once the spacers etc are in place) with the bulk of the spline about half the width of the slots in the pulley!!!
Question is - do I have an odd crank?  Is it a different model that can be identified (maybe I can get a different pulley?).
Man I really don't want to pull a fresh built motor (with all the roller bearing conversion - blah blah) and have to replace a crank at great cost and time.
I will send a picture off to Bob Newby and see if he can help - and will post a picture here once I get home (at work already).
Any thoughts on what's going on with the spline greatly appreciated.

cheers Raymond.
BSA A10 Cafe Racer project
Scotland

Online bsa-bill

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Re: A10 crankshaft spline
« Reply #1 on: 06.09. 2016 09:33 »
Hi Raymond
Excuse me if this is obvious and you have it covered.
what you described sounds like the crank with cushdrive spline on it, first pic is how the crankend should look like, second one is of the Cush drive assemble note part number 42-??69 (third up from the bottom) is this stuck on the crank spline?
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline duTch

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Re: A10 crankshaft spline
« Reply #2 on: 06.09. 2016 10:48 »

  S-Sam, sounds crazy, but send us a pic too, and lets please get something else sorted; pulleys and belts, chains and sprockets  *wink2*
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 beesa71

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Re: A10 crankshaft spline
« Reply #3 on: 06.09. 2016 11:36 »
bsa-bill; that looks like a B25 crank in the picture I see in your post. Were you meaning to add a picture of an A10 alternator crank in your description?

Doesn't the cush drive adaptor pretty much fit flush up to the outer end of the crank before the inner end of the thread starts and therefore there is, so to speak, no spline then showing?

Paul.

Offline duTch

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Re: A10 crankshaft spline
« Reply #4 on: 06.09. 2016 11:58 »

 
Quote
Doesn't the cush drive adaptor pretty much fit flush up to the outer end of the crank before the inner end of the thread starts and therefore there is, so to speak, no spline then showing?

Paul, I'm fairly sure that the cush-nut is held hard-up against the inner sleeve to tighten up the bearing and all the shebang-bits in between, at least on my LJ (adapted to Plunger) crank which has  a slightly different setup, but works out the same; so I'm agreeing with what you say, but maybe not so 'flush', but the sleeve hanging over a bit.
 I think B-Bill just stuck the pic as an example, until S-Sam gives us a pic, we won't know for sure.
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 Slippery Sam

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Re: A10 crankshaft spline
« Reply #5 on: 06.09. 2016 13:29 »
Yeh - this thread doesn't work very well without a pitcture does it?
Bill - the spline looks like the one in the photo - but instead of the plain shaft - the spline continues right to the thread but at a reduced width.  So the inner half of the spline is as per the photo and the spline to the thread is the same pitch, just about half the width of the spline in your photo.
The cush drive inner spline is identical to the pulley I have - and neither fit properly because they are both designed for a plain uniform spline like the one in your photo but all the way to the thread.
While stuck at work over lunchtime I trawled google again and can find loads of pictures of the A10 crank with the uniform spline - but not a single hit on one like mine - I have to say I'm concerned.  So will definately post up a picture at tea time tonight.
best I can do for now is add a drawing:

BSA A10 Cafe Racer project
Scotland

Online bsa-bill

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Re: A10 crankshaft spline
« Reply #6 on: 06.09. 2016 14:27 »
OK S Sam, thought I 'd just eliminate the obvious,. looking forward to the pic when you get it sent.
Just wondering if this is for an alternator crank version, never seen one in real life but someone on here will have
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline Topdad

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Re: A10 crankshaft spline
« Reply #7 on: 06.09. 2016 15:27 »
I think Bill as already posted what I was thinking ie could this be an alternator crankshaft ,does anybody know what they look like ?
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Offline Topdad

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Re: A10 crankshaft spline
« Reply #8 on: 06.09. 2016 15:30 »
whoops sorry bill typed the prev post over an hour ago and got sidetracked  pressed send without checking and there was yours :D
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Offline Klaus

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Re: A10 crankshaft spline
« Reply #9 on: 06.09. 2016 15:56 »
Hi Sam,

I rum most of my bikes with a belt and its only one spline looks like new.
The others are all damaged by a losen cushdrife like you show in your drawing.

All pullys will fit this spline. The only thing you have to do is a little regrind the sharp edges with a file.

Dont care about the lost material from the spline. The pully will sit about half an insh at the healthy spline.
You have to tighten verry well the nut and fit this with a thread lock.

Be shure the belt is in  no hard tension. Correkt tension is when you can turn the belt 90 degrees in the middle.
This seems first sight the belt is slack, but this is the correkt tension.

I use this belt drive since many years and no problems with this.
There many advantages,no oil in the primary, no chain wear, allways the same tension, no noisy rattle, no drag no slipp with the clutch.

This all worth the money you ve spend on it.

cheers Klaus


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Online bsa-bill

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Re: A10 crankshaft spline
« Reply #10 on: 06.09. 2016 15:57 »
no problem Bob, done that a few times myself, my biggest problem though is replying  and then forgetting to press post *roll*
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline Slippery Sam

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Re: A10 crankshaft spline
« Reply #11 on: 06.09. 2016 17:02 »
Hi Sam,

I rum most of my bikes with a belt and its only one spline looks like new.
The others are all damaged by a losen cushdrife like you show in your drawing.

All pullys will fit this spline. The only thing you have to do is a little regrind the sharp edges with a file.

Dont care about the lost material from the spline. The pully will sit about half an insh at the healthy spline.
You have to tighten verry well the nut and fit this with a thread lock.

Be shure the belt is in  no hard tension. Correkt tension is when you can turn the belt 90 degrees in the middle.
This seems first sight the belt is slack, but this is the correkt tension.

I use this belt drive since many years and no problems with this.
There many advantages,no oil in the primary, no chain wear, allways the same tension, no noisy rattle, no drag no slipp with the clutch.

This all worth the money you ve spend on it.

cheers Klaus

Thank you very much Klaus - I think that's it - spline worn by dodgy cush drive.  I was pointed at this elsewhere today.  Looks and sounds exactly what I have.  It looks so neat it's hard to initially identify it as wear, but that's exactly what's happened.
I have heard of people having to loctite things on - so I will be very careful and will dress it, prepare it and will loctite the nut on.  The pulley is fresh and a tight fit so will heat before fitting to get a good solid fit on the bit of good spline I have left - and make sure I get it well home and flush.

Thanks also to all other contributors - any and all pointers welcome - I appreciate the tips and things to check and eliminate.
I'm not so gutted as I felt earlier - but will watch what I'm doing now that I have the understanding of what's going on and will keep an eye on it - easy to do with no oil flying about  *smile*

As they say "Get In!!!!"

cheers fellas
Raymond. (will post a pic later)
BSA A10 Cafe Racer project
Scotland

Offline duTch

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Re: A10 crankshaft spline
« Reply #12 on: 06.09. 2016 20:18 »

Quote
S-Sam, sounds crazy, but send us a pic too, and lets please get something else sorted; pulleys and belts, chains and sprockets  *wink2*

 I wasn't aware it is a belt drive, that's where pictures can save a lot of hassle
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 Slippery Sam

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Re: A10 crankshaft spline
« Reply #13 on: 06.09. 2016 20:57 »
Picture of offending crank
First picture is worn spline

Next with roller bearing fitted is my old crank - needs a grind - bit ironic this one in my spares box has a good spline

Cleaned everything up and went ahead - everything fitted well and no movement.
BSA A10 Cafe Racer project
Scotland

Offline RichardL

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Re: A10 crankshaft spline
« Reply #14 on: 06.09. 2016 21:22 »
So, the wear is on the driving edges of the splne. Makes perfect sense to me, except, I think the cush drive should have avoided such deep wear. Do you know where the crank came from and if it had a functional cush drive?

Richard L.

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