BritBike Forum logo
BritBike Sponsor BritBike Sponsor BritBike Sponsor
BritBike Sponsor

BritBike Sponsor

BritBike Sponsor
BritBike Sponsor BritBike Sponsor BritBike Sponsor
The Bonneville Shop JRC Engineering dealers
Home | Sponsors, Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons, "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Member Spotlight
Towner
Towner
Lower Rhine Area, Germany
Posts: 341
Joined: March 2008
Show All Member Profiles 
Shout Box
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Who's Online Now
15 registered members (BrettF), 144 guests, and 388 spiders.
Key: Admin, Global Mod, Mod
Newest Members
Tim Pedder, blayde54, Davenz13, Sean65, Rerock
10478 Registered Users
Top Posters(30 Days)
NickL 92
franko 77
Triless 71
Popular Topics(Views)
748,939 mail-order LSR
Forum Statistics
Forums34
Topics68,852
Posts670,679
Members10,478
Most Online3,995
Feb 13th, 2017
Like BritBike.com on Facebook

Previous Thread
Next Thread
Print Thread
Rate Thread
Cylinder head broken fin replacement #720408
12/29/17 7:54 pm
12/29/17 7:54 pm
Joined: Dec 2017
Posts: 211
England
F
ferretjuggler Offline OP
BritBike Forum member
ferretjuggler  Offline OP
BritBike Forum member
F

Joined: Dec 2017
Posts: 211
England
I've got one small fin broken off my A65 cylinder head.
I don't have the missing piece of fin, that has gone AWOL long ago.

So I have to find something that I can make a substitute fin from and then get it TIG welded onto the head.

I'm thinking that the best source would be a scrap British cylinder head from a similar era.
Nothing fancy maybe a Bantam or C15 head which is beyond economical repair.

So is there anything wrong with my cunning master plan ?

Support your #1 BSA Forum and our favorite sponsors

Check out BSA on e-bay: BSA Parts in UK, BSA Motorcycles in UK, BSA Parts in North America, BSA Motorcycles in North America

 
Re: Cylinder head broken fin replacement [Re: ferretjuggler] #720429
12/29/17 10:32 pm
12/29/17 10:32 pm
Joined: Nov 2009
Posts: 633
B
bon Offline
BritBike Forum member
bon  Offline
BritBike Forum member
B

Joined: Nov 2009
Posts: 633
Have a look for a similar, but scrap head, maybe one thats dropped a valve at some stage, off eBay, and get it tigged. It saves you filing the new piece of fin to shape. Nothing wrong with your plan i would suggest.

Re: Cylinder head broken fin replacement [Re: ferretjuggler] #720476
12/30/17 11:31 am
12/30/17 11:31 am
Joined: Aug 2001
Posts: 4,251
argyll. scotland, uk
gavin eisler Offline
BritBike Forum member
gavin eisler  Offline
BritBike Forum member

Joined: Aug 2001
Posts: 4,251
argyll. scotland, uk
A65 head fins have a distinct taper from root to tip, make sure the donor is similar or it will stick out when repaired.
SRM do a good job of fin repairs.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: Cylinder head broken fin replacement [Re: ferretjuggler] #720498
12/30/17 3:10 pm
12/30/17 3:10 pm
Joined: Nov 2011
Posts: 4,838
U.S.
Magnetoman Online content

BritBike Forum member
Magnetoman  Online Content

BritBike Forum member

Joined: Nov 2011
Posts: 4,838
U.S.
Originally Posted by ferretjuggler
So I have to find something that I can make a substitute fin from and then get it TIG welded onto the head.
Unless the welder were able to attach the replacement piece perfectly parallel with the other fins the repair will be quite obvious. Instead, a better job usually can be done by building up the missing material with TIG and "sculpting" it into the right shape. This is especially true when the missing piece is relatively small.

Re: Cylinder head broken fin replacement [Re: Magnetoman] #720502
12/30/17 3:46 pm
12/30/17 3:46 pm
Joined: Dec 2017
Posts: 211
England
F
ferretjuggler Offline OP
BritBike Forum member
ferretjuggler  Offline OP
BritBike Forum member
F

Joined: Dec 2017
Posts: 211
England
Originally Posted by Magnetoman
Originally Posted by ferretjuggler
So I have to find something that I can make a substitute fin from and then get it TIG welded onto the head.
Unless the welder were able to attach the replacement piece perfectly parallel with the other fins the repair will be quite obvious. Instead, a better job usually can be done by building up the missing material with TIG and "sculpting" it into the right shape. This is especially true when the missing piece is relatively small.

Yes I've had that done before on a Triumph twin head.
Quite successful but as I've got the opportunity to get one of the toolmakers at work to do the welding FOC I can only ask so much.
I suppose that I could weld it myself but I'm so far out of practice that I'd need a couple of hours practice first.
Not really practical when the job is a "foreigner" on a machine I'm not really supposed to be using.
I do actually own a spare A65T head from an earlier model.
I could use this as a donor but it seems a shame as it's a repairable head.
I'm thinking that if I can make myself a replacement fin, I could design a special clamp to hold it exactly in the right place during welding.
Yeah, maybe it would be easier just to build up a fin from weld.
Maybe time for a rethink ?
Maybe time to find someone with an AC TIG set in their shed ?


Moderated by  Allan Gill, Jon W. Whitley 


Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Powered by UBB.threads™ PHP Forum Software 7.6.2