Author Topic: Alloy head bolts  (Read 2386 times)

Online orabanda

  • Wise & Enlightened
  • *
  • Join Date: Nov 2008
  • Posts: 1010
  • Karma: 21
Alloy head bolts
« on: 18.01. 2014 13:21 »
Hi All,
Can someone please supply the lengths of the bolts which make up a set for (a) a 1954 A7 SS, and (b) a 1958 A10 Super Rocket?

Should all or some of the bolts be of a "waisted" type?

Thanks,

Rickity Dick

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8253
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: Alloy head bolts
« Reply #1 on: 19.01. 2014 01:16 »
G'day mate, the SS and the SR are the same length, the longer 6 are wasted. Sorry can't help with measurements right now.
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline wilko

  • Resident Legend
  • *****
  • Join Date: Mar 2010
  • Posts: 681
  • Karma: 4
Re: Alloy head bolts
« Reply #2 on: 19.01. 2014 23:16 »
I wouldn't recommend alloy bolts as they will keep stretching each time you re-torque. Steel is better.

Offline Rocket Racer

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 1431
  • Karma: 16
  • A kiwi with a racing A10 rig and too many projects
    • NZ Classic Sidecar Racing
Re: Alloy head bolts
« Reply #3 on: 19.01. 2014 23:43 »
I wouldn't recommend alloy bolts as they will keep stretching each time you re-torque. Steel is better.

brilliant  *yeah*
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand

Online RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 5058
  • Karma: 48
Re: Alloy head bolts
« Reply #4 on: 20.01. 2014 12:53 »
Richard,

I assume you have no question about the part numbers. It seems that Burton Bike Bits http://burtonbikebits.net  lists bolt sizes on their price list. My A7 and A10 are both apart right now, so I will try to get measurements off of the actual bolts this evening.

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Online trevinoz

  • Newcastle, N.S.W. Australia.
  • Wise & Enlightened
  • *
  • Join Date: Jul 2006
  • Posts: 2902
  • Karma: 67
Re: Alloy head bolts
« Reply #5 on: 20.01. 2014 23:01 »
Richard, (Rickity)

Head bolts are:-     Long, waisted - 3", original bolt- 13/16" thread, pattern- 1" thread.
                           Medium, waisted, 2-5/8', original- 7/8" thread, pattern- 1" thread.
                           Short, plain shank, 1-5/8", original- 11/16" thread, pattern- 1-1/16" thread.

We shall see if Richard L's measurements are the same.

I suppose it's a matter of time before they call you "wrinkly".

Trev.

Online RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 5058
  • Karma: 48
Re: Alloy head bolts
« Reply #6 on: 20.01. 2014 23:24 »
Better than "shriveled".
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Online orabanda

  • Wise & Enlightened
  • *
  • Join Date: Nov 2008
  • Posts: 1010
  • Karma: 21
Re: Alloy head bolts
« Reply #7 on: 21.01. 2014 03:10 »
Trev,
As long as they don't call me late for lunch!

You are a gentleman and a scholar, but just a tad too cheeky; a typical Eastern sider

As for you, manosound: - Thanks as well!

Richard

Online RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 5058
  • Karma: 48
Re: Alloy head bolts
« Reply #8 on: 21.01. 2014 03:56 »
Richard,

Here are the dimensions of my head bolts shown in the photos. I didn't follow good engineering practice because the number of decimal places isn't consistent, but I think you will get past that. Obviously, I didn't round to nominal dimensions (like, in 1/16 ths of an inch), but just entered the caliper readings for the one bolt measured of each type. The A10 bolts should be correct stock or replacements. I think the bolts from the A7 are stock or correct replacements also, but I really don't know yet, not having gotten too much into it since purchase in November. Also included is a picture of the head of one of the A7 bolts where "Wiley R" is formed. I would be interested to know if anyone is aware if this signifies an original part.

Richard L.

P.S. The drawing is something of a mess because of using the A10 seat as a photo table. Sorry about that.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Online trevinoz

  • Newcastle, N.S.W. Australia.
  • Wise & Enlightened
  • *
  • Join Date: Jul 2006
  • Posts: 2902
  • Karma: 67
Re: Alloy head bolts
« Reply #9 on: 21.01. 2014 20:11 »
Richard L.
                  Wiley bolts were original fit. Quite a few heads about the bike were so marked.

Trev.

Offline bikerboy

  • Valued Contributor
  • ****
  • Join Date: Dec 2011
  • Posts: 362
  • Karma: 4
Re: Alloy head bolts
« Reply #10 on: 19.02. 2014 03:28 »
I have found this useful in the past

http://stainlessbits.com/link12.html

You look for the part number of the bolt/nut and it gives you the spec

Offline beezermacc

  • Resident Legend
  • *****
  • Join Date: Dec 2011
  • Posts: 993
  • Karma: 39
  • Not for the purist!
    • Priory Magnetos Ltd.
Re: Alloy head bolts
« Reply #11 on: 04.03. 2014 00:10 »
I find that the head bolts supplied by the likes of MCA and Wassell are too short. If you measure the depth of the aluminium plus the depth of the threads and add about 2mm for the thick washer you'll find that the bolts supplied are about 8-10mm too short. I've come across a few people stripping threads recently. I have obtained some high tensile socket cap bolts which I have cut to the correct length to ensure using all the available thread in the barrels.
Priory Magnetos Ltd - A10 spares, magneto and dynamo refurbs. www.priorymagnetos.co.uk

Online bsa-bill

  • Wise & Enlightened
  • *
  • Join Date: Mar 2006
  • Posts: 5454
  • Karma: 62
Re: Alloy head bolts
« Reply #12 on: 04.03. 2014 09:12 »
Quote
correct length to ensure using all the available thread in the barrels.

I think this is maybe not so good, how do you know if your clamping or bottoming
(plus if my last project is any guide there needs to be room in there for POs accumulated crud, not that anyone here would allow that to happen)
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 Briz

  • A's Best Friend
  • ***
  • Join Date: Apr 2013
  • Posts: 209
  • Karma: 7
  • West Norfolk UK
    • Custom cycle developments
Re: Alloy head bolts
« Reply #13 on: 04.03. 2014 11:04 »
I find that the head bolts supplied by the likes of MCA and Wassell are too short. If you measure the depth of the aluminium plus the depth of the threads and add about 2mm for the thick washer you'll find that the bolts supplied are about 8-10mm too short. I've come across a few people stripping threads recently. I have obtained some high tensile socket cap bolts which I have cut to the correct length to ensure using all the available thread in the barrels.

Yes, I've found this. Especially the shortest bolts. Inadequate thread engagement.
The way to avoid bottoming out is to test & measure.
I too used top use quality allen bolts, but harder to find now in BSF threads.

Offline beezermacc

  • Resident Legend
  • *****
  • Join Date: Dec 2011
  • Posts: 993
  • Karma: 39
  • Not for the purist!
    • Priory Magnetos Ltd.
Re: Alloy head bolts
« Reply #14 on: 04.03. 2014 21:29 »
Quote
correct length to ensure using all the available thread in the barrels.

I think this is maybe not so good, how do you know if your clamping or bottoming
(plus if my last project is any guide there needs to be room in there for POs accumulated crud, not that anyone here would allow that to happen)

I run the bolts down into the barrels without fitting the head, measure the free length under the socket cap and compare this with the depth of aluminium of the cylinder head. Obviously it is necessary to do this sort of check when using non-standard parts, but better than using the commercially supplied stuff which is too short and leads to stripped threads.
Priory Magnetos Ltd - A10 spares, magneto and dynamo refurbs. www.priorymagnetos.co.uk