Britbike forum

Classic British SparesKlempf British PartsBaxter CycleBritBike Sponsor SteadfastCyclesThe Bonneville ShopLowbrow CustomsGirling Classic MotorcycleLucas Classic MotorcycleHepolite PistonsIndustrial tec supplyJob Cycle

Upgrade to Premium membership HERE! Premium Membership


New Sponsor post
15% Off Black Friday Sale
by The Bonneville Shop - 11/24/22 5:51 pm
New FAQ post
Member Spotlight
Spitfire Ken
Spitfire Ken
Illinois
Posts: 378
Joined: April 2013
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Top Posters(30 Days)
kevin 55
Top Likes Received (30 Days)
Bry 24
Newest Members
Hedgehog65, NDarwin, Bas classic bikes, lojo, Doug McLaren
12,333 Registered Users
Who's Online Now
6 members (Hugh Jörgen, Tridentman, Magnetoman, DMadigan, Jon W. Whitley, HayMike), 18 guests, and 27 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums35
Topics76,682
Posts782,987
Members12,333
Most Online204
Jul 10th, 2022
Previous Thread
Next Thread
Print Thread
Joined: Sep 2022
Posts: 6
Likes: 2
Britbike forum member
OP Offline
Britbike forum member
Joined: Sep 2022
Posts: 6
Likes: 2
Good day, Thank's for looking,
I've got a 62'-66' range A65, (no #'s ever on Eng). My question is I have a 1" round metal plate screwed on to the Inner Timing case top side, it is stamped 712, I'm hearing it may be the Tach gear ratio, if so does this mean that this Eng. may have a CR box ??. As why BSA affixing it to the Eng. externally ? ,kind of making it a big deal. ?

British motorcycles on eBay
Joined: Aug 2001
Posts: 5,167
Likes: 118
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 5,167
Likes: 118
Welcome aboard here! Lots of good folks with help or ideas.
The tag you mention is on top of a transmission of the early Speedo drive design. The cable will attach to the bottom of the trans, not a later version rear wheel gearbox. Pros / Cons on both designs, but my opinion the early method was just fine, and likely changed for cost cutting purposes, not fault. So, the small tag has Trans Spdo drive ratio info on it. I think that changed with the rear wheel gearbox used from ‘66? So your bike is likely using a ‘65 or earlier motor.
What numbers do you find on the frame? Left side at either: front LF engine mount frame lug, or up on the LH side steering head “sheet metal” brace? Maybe it’s a Pre ‘66 bike? You will want to accumulate some books, they’re cheap, and also con be found on line by the sponsors of this site. Check the CBS site at the top for shop and parts books supplied on the site as a help.
Really? No numbers ever? Have you looked LH side motor just below the cylinder base flange? We need photos here!!

Last edited by KC in S.B.; 09/21/22 4:05 pm.

Down to ‘69 T120R now a Tr6R tribute bike
‘70 TR6C “happy in the hills”
‘67 A65L numbers match, “best effort” from basket *
Gone:
‘66 A65L“in ‘95 getting back in the game”+ empty ‘67 Case&Frame *
‘69 A65L
‘68 A65L “red bike” basket, sold & made whole by BB member
‘68 A65F nice Tribute bike
‘65 A50L bitsa from spare parts, Son’s fun
‘62 A10 Spitfire
‘65 T120R sad case, saved by BB member
'65 XLCH “scratched THAT itch”……
‘93 K1100RS heavy metal (should be gone, still here…)
Joined: Sep 2022
Posts: 6
Likes: 2
Britbike forum member
OP Offline
Britbike forum member
Joined: Sep 2022
Posts: 6
Likes: 2
Thank's for your insight, the Engine only I bought recently no history from seller, it was a estate sale item, no #'s. What I'm trying to figure out is if possibly the transmission is CR and ended up requiring the Tag to identify about non-standard gearing ratio's inside? I've heard of older Rocket Eng.'s with CR. Sorry no Pic.'s but had trouble download.. Good day, Mike

Joined: Aug 2001
Posts: 5,167
Likes: 118
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 5,167
Likes: 118
There are close ratio A65 transmissions. The round tag on top of the trans is not a reference to transmission gearing, wide or close ratio gearing. It is only related to the speedometer calibration. Look at the bottom RH side of the trans, you will see the treaded Speedo cable attachment point.


Down to ‘69 T120R now a Tr6R tribute bike
‘70 TR6C “happy in the hills”
‘67 A65L numbers match, “best effort” from basket *
Gone:
‘66 A65L“in ‘95 getting back in the game”+ empty ‘67 Case&Frame *
‘69 A65L
‘68 A65L “red bike” basket, sold & made whole by BB member
‘68 A65F nice Tribute bike
‘65 A50L bitsa from spare parts, Son’s fun
‘62 A10 Spitfire
‘65 T120R sad case, saved by BB member
'65 XLCH “scratched THAT itch”……
‘93 K1100RS heavy metal (should be gone, still here…)
1 member likes this: Allan G
Joined: May 2013
Posts: 8,909
Likes: 288
Britbike forum member
Offline
Britbike forum member
Joined: May 2013
Posts: 8,909
Likes: 288
The only way your going to know if it has a close box fitted or not is to pull the transmission. I didn’t know of any close ratio boxes being fitted prior to 1965, but that doesn’t mean there wasn’t any… just news to me if there was.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (now rebuilt)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Joined: Sep 2022
Posts: 6
Likes: 2
Britbike forum member
OP Offline
Britbike forum member
Joined: Sep 2022
Posts: 6
Likes: 2
Yeah wishful thinking my part.it's up to a 66' There's a reason I suspected it could be at least a good engine. It was kind of a gamble as the engine came up for sale, a non motorcycle enthusiast got it through some 'estate sale' with no Info. . The Eng. was covered with cosmolien and good fins ect. I figured someone cared about it, I bought it. Turns out to have been overhauled, with never run new top end as well,... I was due some luck. I understand I've got to really disassemble to know for sure, and I'm not going to take a presumably tight Eng apart for this, I quess wait and see how it performs with Elect. Ign. and couple 1 3/16' AMAL 389's. I've got a 69' Firebird Scrambler rolling frame for it. Thank's again for the pointers.....Mike

1 member likes this: Allan G
Joined: Dec 2013
Posts: 6,540
Likes: 313
DOPE
Offline
DOPE
Joined: Dec 2013
Posts: 6,540
Likes: 313
just my opinion, but i have seen enough "overhauled" engines sold apart from a chassis that i would be suspicious of anything. ive seen pistons put back aftrr seizures, misplaced crank pinion keys, missing oil pump slider blocks, and so on.

look over everything you can see before you run it, especially cam timing.


i'm old enough to remember when patriotism meant not trying to overthrow the government.
3 members like this: NickL, Allan G, pushrod tom
Joined: Sep 2022
Posts: 6
Likes: 2
Britbike forum member
OP Offline
Britbike forum member
Joined: Sep 2022
Posts: 6
Likes: 2
I'll try to 'pre oil' around. Defiantly look over cam timing, no rush, I'm putting in Boyer so good time to look at that. I did find the crank pinion nut not tight enough, and missing the tab washer, yikes. I agree it's a gamble buying Eng.sight unseen, seems like the majority of the Brit. bike people are better than most, with those exceptions of course Good used engines are rather rare. Seems very acceptable so far..

Joined: Aug 2001
Posts: 6,042
Likes: 140
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 6,042
Likes: 140
1965 was the last year of the speedo drive off the transmission. If this engine has it, you should see a threaded cable drive on the bottom of the inner timing cover. Inside the cover, the cable drive has a worm gear, which meshes with another gear that runs off the tranny lay shaft.

I also have another inner timing cover, I think it's a '66, which has a blanked-off boss on the bottom of the inner timing cover, where the speedo cable drive was on earlier models. By '67, or perhaps later in '66, they changed the casting to remove the boss altogether.

1965 was also the last year of the ball bearing drive-side main, later models employing a roller bearing. You probably can't tell which it is from the outside, but if you dig into the lower it will become relevant.

Another way to date the engine is by the cylinder head bolts: Up through 1965, two of the bolts are 5/16" diameter (can't remember if it's the front two or rear two). '66 and later, all head bolts are 3/8" diameter. I have also seen a cylinder barrel where all four inner head bolts are 5/16"! I have no idea what year that barrel was from, presumably '62 or '63.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
2007 Triumph Bonneville Black
Joined: Sep 2022
Posts: 6
Likes: 2
Britbike forum member
OP Offline
Britbike forum member
Joined: Sep 2022
Posts: 6
Likes: 2
Thank's for the Info. Mark, I see my Cyl head fastners are all 3/8" with the exception of the 1 center short bolt which is 5/16 The Eng. has the Tach. drive with adapter at the bottom inner timing, worm gear driven. Looking at the Eng. cases style, Primary case with the 2 Insp. plugs over clutch with a teardrop plugs cover. Clutch cable adapter is a hollow steel tube that fits abutment, So I figured 62'-66' range. now with the head bolt info, looks more like landing on a 66', for now unless that gets ruled out somehow. Cheers, Mike

Joined: Aug 2001
Posts: 6,042
Likes: 140
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 6,042
Likes: 140
Originally Posted by White Lightning
Thank's for the Info. Mark, I see my Cyl head fastners are all 3/8" with the exception of the 1 center short bolt which is 5/16 The Eng. has the Tach. drive with adapter at the bottom inner timing, worm gear driven. Looking at the Eng. cases style, Primary case with the 2 Insp. plugs over clutch with a teardrop plugs cover. Clutch cable adapter is a hollow steel tube that fits abutment, So I figured 62'-66' range. now with the head bolt info, looks more like landing on a 66', for now unless that gets ruled out somehow. Cheers, Mike

That's speedometer drive, not tach drive, on the bottom of the inner timing cover. The tach drive is on the front end of the inner timing cover.

So it sounds like the inner timing cover is pre-'66. Likewise, the primary cover with the teardrop-shaped cover over the clutch center is pre-'66. The cylinder head, or at least the cylinder barrel, on the other hand, is '66 or later (that is, the cylinder head could have been drilled to match the barrel). In other words, you have a mixture. The most likely scenario is that the entire lower engine is '62-'65, and the cylinder barrel and maybe the head were replaced at some time.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
2007 Triumph Bonneville Black
Joined: Jan 2014
Posts: 2,333
Likes: 431
Britbike forum member
Offline
Britbike forum member
Joined: Jan 2014
Posts: 2,333
Likes: 431
Originally Posted by White Lightning
Thank's for the Info. Mark, I see my Cyl head fastners are all 3/8" with the exception of the 1 center short bolt which is 5/16 The Eng. has the Tach. drive with adapter at the bottom inner timing, worm gear driven. Looking at the Eng. cases style, Primary case with the 2 Insp. plugs over clutch with a teardrop plugs cover. Clutch cable adapter is a hollow steel tube that fits abutment, So I figured 62'-66' range. now with the head bolt info, looks more like landing on a 66', for now unless that gets ruled out somehow. Cheers, Mike


The head centre bolt is actually a 3/8 with reduced head.
The rear bolts on the early ones were 5/16 but can easily be enlarged to 3/8
so that's no guide really. Valve diameters changed as well as springs etc.
It's difficult to measure oil pressure on an early a65 engine so as others
have said, you're taking a gamble just running it without knowing what the
bottom end etc is like.

Last edited by NickL; 09/25/22 1:42 am.
1 member likes this: Allan G
Joined: Aug 2001
Posts: 5,167
Likes: 118
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 5,167
Likes: 118
Well, we all have our personal experiences, and offer that as advice. Sometimes our experience is not an accurate of manufacturing. I can attest to having a 1966, A65, I have had with a 5/16 center bolt original condition. That center bolt was enlarged to 3/8 by the repair shop at their advice. Aside from other things, I am quite sure that any head with a 5/16 center bolt is original, and an indication of earlier design. Finding one with a larger center bolt can easily mean it was enlarged as stated before, or original.


Down to ‘69 T120R now a Tr6R tribute bike
‘70 TR6C “happy in the hills”
‘67 A65L numbers match, “best effort” from basket *
Gone:
‘66 A65L“in ‘95 getting back in the game”+ empty ‘67 Case&Frame *
‘69 A65L
‘68 A65L “red bike” basket, sold & made whole by BB member
‘68 A65F nice Tribute bike
‘65 A50L bitsa from spare parts, Son’s fun
‘62 A10 Spitfire
‘65 T120R sad case, saved by BB member
'65 XLCH “scratched THAT itch”……
‘93 K1100RS heavy metal (should be gone, still here…)

Moderated by  Jon W. Whitley 

Link Copied to Clipboard
British Cycle SupplyMorries PlaceKlempf British PartsBSA Unit SinglesPodtronicVintage MagazineBritBike SponsorBritish Tools & FastenersBritBike Sponsor






© 1996-2022 britbike.com
Powered by UBB.threads™ PHP Forum Software 7.7.5