BritBike Forum logo
BritBike Sponsor BritBike Sponsor BritBike Sponsor
BritBike Sponsor

BritBike Sponsor

BritBike Sponsor
BritBike Sponsor BritBike Sponsor BritBike Sponsor
  JWood Auction  
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
Photo posting tutorial

Member Spotlight
58a10
58a10
texas
Posts: 252
Joined: March 2006
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
220 registered members (57nortonmodel77), 1,640 guests, and 555 spiders.
Key: Admin, Global Mod, Mod
Newest Members
revans, Gilly, XTINCT, Bruce Roberts, Brian Ellery
9959 Registered Users
Top Posters(30 Days)
btour 191
koan58 99
Stuart 86
NickL 73
Popular Topics(Views)
439,034 mail-order LSR
Forum Statistics
Forums33
Topics65,292
Posts632,463
Members9,959
Most Online3,995
Feb 13th, 2017
Like BritBike.com on Facebook

Previous Thread
Next Thread
Print Thread
Rate This Thread
#126518 - 10/18/07 4:18 pm Non-matching cases question  
Joined: Jul 2007
Posts: 45
Jake Hartley Offline
BritBike Forum member
Jake Hartley  Offline
BritBike Forum member

Joined: Jul 2007
Posts: 45
Oklahoma City OK
Is it advisable to assemble and engine from non-matching cases from the same year and type on a 650?


"He who makes a beast of himself gets rid of the pain of being a man"
Support Your #1 BritBike Forum!
Membership Type! Free
Member
Premium
Member
Premium Life
Member
Vendor
Member
Site
Sponsor
Recognition No Premium Member Premium Life member (5 years) Vendor Member Site Sponsor Membership
Post commercial threads No No No Yes Yes
Custom title No Yes Yes Yes Yes
Upload avatar & photos No Yes Yes Yes Yes
Link avatar & photos Yes Yes Yes Yes Yes
Private Message Storage: 10 100 100 100 100
Length of signatures 255 600 600 600 600
Removes this very advert island between post 1&2 No Yes Yes Yes Yes
Price Free $12.90/year $105.00 No End
$55.00/5 years
$210.00/year
($17.50/month)
Email
Click on button >>
  Premium Member Premium Life member Vendor Member Site Sponsor Membership
#126519 - 10/18/07 4:51 pm Re: Non-matching cases question  
Joined: Oct 2003
Posts: 11,110
RF Whatley Online content
BritBike Forum member
RF Whatley  Online Content
BritBike Forum member

Joined: Oct 2003
Posts: 11,110
North Georgia, USA
Depends on the year, but usually "No".


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
#126520 - 10/18/07 4:59 pm Re: Non-matching cases question  
Joined: Jul 2007
Posts: 45
Jake Hartley Offline
BritBike Forum member
Jake Hartley  Offline
BritBike Forum member

Joined: Jul 2007
Posts: 45
Oklahoma City OK
year would be late 71, early 72. can you elaborate? I am assuming differences in alignment of the two halves, etc....


"He who makes a beast of himself gets rid of the pain of being a man"
#126521 - 10/18/07 5:16 pm Re: Non-matching cases question  
Joined: Aug 2006
Posts: 103
JGTR6R Offline
BritBike Forum member
JGTR6R  Offline
BritBike Forum member

Joined: Aug 2006
Posts: 103
Andover, MN
I have a very early 72 (aug 71 build) and the case halves are stamped with different wittness numbers. I assumed it was from the factory using up halves that had already been machined with new halves made for the bearing change. I am second owner (bought it when it was 2 years old) and don't think it was a reworked motor.


Mike D
72 650 Tiger 4 speed
#126522 - 10/18/07 6:08 pm Re: Non-matching cases question  
Joined: Dec 2004
Posts: 8,891
kommando Online content
kommando  Online Content


Joined: Dec 2004
Posts: 8,891
Scotland
I have same as JG, B44 case halves have different witness numbers but the date stamped is each is less than 7 days apart, one sump stud hole was completely undrilled with no sign of weld. Looks like the factory had 2 crankcase sets in a reject pile and made 'Good' sets by mixing.

Crank spins fine and the cylinder deck is level.

#126523 - 10/18/07 8:55 pm Re: Non-matching cases question  
Joined: Jul 2007
Posts: 45
Jake Hartley Offline
BritBike Forum member
Jake Hartley  Offline
BritBike Forum member

Joined: Jul 2007
Posts: 45
Oklahoma City OK
outside of the circumstances of the last two posters, what are the pitfalls of assemblying an engine from two "odd" halves? I assume (bad thing, I know), that some engines have replacement case "sides " put on when one side was damaged beyond repair.


"He who makes a beast of himself gets rid of the pain of being a man"
#126524 - 10/19/07 3:44 am Re: Non-matching cases question  
Joined: Jul 2007
Posts: 45
Jake Hartley Offline
BritBike Forum member
Jake Hartley  Offline
BritBike Forum member

Joined: Jul 2007
Posts: 45
Oklahoma City OK
ok, y'all mentioned witness numbers: are these representative of them?

s/n side case has this series of numbers on the bottom, near the mating surface: 6 26

oil pump side has this series of numbers in the same place: 6 28

oil pump also has a number in the cam gear case 71-1081 and AM (H?)-2

any help?


"He who makes a beast of himself gets rid of the pain of being a man"
#126525 - 10/19/07 6:25 am Re: Non-matching cases question  
Joined: Dec 2004
Posts: 8,891
kommando Online content
kommando  Online Content


Joined: Dec 2004
Posts: 8,891
Scotland
Witness marks are normally a set of small numbers (usally 3 for BSA) stamped out of sight on the bottom of the cases, they were stamped on the case halves at the first machining step in the factory and meant that they could be tracked if they were separated but they were always machined together. By machining them together it meant the maching accuracy could be more forgiving as each half would be wrong by the same amount, also common bores would be parallel.

The critical ares to look for on unmatched cases are the main bearing bores (hence the check for a fee spining crank) and the deck for the barrel being flat. There are other potential problems but they are not so important.

Service cases were always supplied in pairs, so if a rod damaged one crankcase half then a pair of cases was supplied for the warrenty repair.

#126526 - 10/19/07 12:32 pm Re: Non-matching cases question  
Joined: Jul 2007
Posts: 45
Jake Hartley Offline
BritBike Forum member
Jake Hartley  Offline
BritBike Forum member

Joined: Jul 2007
Posts: 45
Oklahoma City OK
these do in fact have different witness numbers. I will check the other areas you mentioned. I have now way of knowing if they were actually together in a running engine, as they were part of a bitsa I am putting together.

thanks for your help!


"He who makes a beast of himself gets rid of the pain of being a man"

Moderated by  John Healy 


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
UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.133s Queries: 14 (0.006s) Memory: 0.8490 MB (Peak: 1.0362 MB) Zlib disabled. Server Time: 2017-11-23 16:43:24 UTC