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#894299 10/29/22 12:51 am
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Buying a (nother) basket/project. It has an a50 frame number and an a65d (?) Engine number which research indicates it's a 65 L/R.

Any knowledgeable folks know the up or downsides to a 65 a65?

I have seen a few threads about heads and valve sizes, and it is sporting dual monoblocks and a speedo and tach but any help on the differences would be appreciated. Also if anyone has experience with the case/main bush conversion in the us, guidance to good machinist also helpful. Motor is free but being unknown and not running it looks like a total teardown


Dave
65 TR6R 68A65T 69 B44VS. 74 T150V 65 A65 D L/R
19 Chieftain
BSA on eBay
DAMadd #894310 10/29/22 8:20 am
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Hi, and congrats on discovering the your machine. In that year the BSA produced 11 variants of the Unit twin design, and over the years, it's more than likely that some parts have been replaced with parts from other years; some for appearance maybe, or some for convenience etc.
I've got an A50D from that year, and it's clear that the company along with their component suppliers, Lucas, Girling, Smith's Reynolds, Wipac made parts that don't appear on any other years parts lists, the headlamp, shrouds, wheel sizes, switches, guards etc, are all unique. I'd just get it running first. If it's purely going to be an occasional ride, I'd stick with a ball bearing drive side and bush timing side.. Thrust bearing appeared on later bikes and that's what caused the trouble. You won't really know what you have till you tear it down and do some research.


Gavin
You can't make a silk purse from a sow's ear.
DAMadd #894314 10/29/22 1:50 pm
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A65D are decent motors. I have been running one since 2006 or so with no engine issues. It has a stock bottom end with a late DD pump and piston type relief.

The valves and ports are a bit different than later motors. IME, the engine likes to rev compared to my 68 engine.

Before you get too far into a 65 L/R, have a good idea what you want when done. As already mentioned, the L/R’s are very different bikes than what came before and after. There were also a lot of running changes in the 2 years they were built. The late production 65’s are likely the easiest to get back to original, but even then, a lot of parts are unique to those bikes.


Never underestimate the human ability to elevate stupid to a whole new level!.
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DAMadd #894315 10/29/22 3:03 pm
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I barely just got a 68 tbolt up and running side covers yet to be painted but it was finishing a dead friends project bike,. This one is more for me.

I notice in internet examples most are red and vary between teardrop and round badges with an a10 style tank. Not really keen on red.
Frame number in the 9000s so I hope that's a late production, going to collect it in a bit, will post a couple pics


Dave
65 TR6R 68A65T 69 B44VS. 74 T150V 65 A65 D L/R
19 Chieftain
DAMadd #894332 10/29/22 7:07 pm
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[Linked Image from i.postimg.cc]

Fresh off the truck
[Linked Image from i.postimg.cc]

Are built in controls a thing for 65's?
[Linked Image from i.postimg.cc]

Last edited by DAMadd; 10/29/22 7:11 pm.

Dave
65 TR6R 68A65T 69 B44VS. 74 T150V 65 A65 D L/R
19 Chieftain
DAMadd #894354 10/30/22 2:06 am
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Built in controls are not a thing on a LR

Last edited by Rich B; 10/30/22 2:06 am.

Never underestimate the human ability to elevate stupid to a whole new level!.
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DAMadd #894378 10/30/22 2:34 pm
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2 throttle cables is a thing for 1965 dual carb tho right? Also is there measurement externally to find the cam and compression ratio. The info about lightning rocket conflicts from various Internet sources (British only tech, spares manual shows multiple ratios possible for l/r while the ads from old publications all say road race trim)
Ordered the parts and service manuals for that year

Looks like it was set up for scrambles with knobby tires, cut down fenders and no lights ( and no tank) but what looks like the original fuel line setup and petcocks still attached- black hose smooth, with crimped ends. 245 miles on the clock but the speedo cable is not attached and really short. Speedo drive on qd rear wheel but the cable comes no where near it. Did bsa ever drive it off the trans?

Last edited by DAMadd; 10/30/22 2:36 pm.

Dave
65 TR6R 68A65T 69 B44VS. 74 T150V 65 A65 D L/R
19 Chieftain
DAMadd #894381 10/30/22 3:08 pm
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A65D have standard ratios in the transmission. If the bike left the factory with a CR gearbox, the engine code would be A65DC.

The speedo drive was from the transmission on that vintage. Different gears were used for different rear ratios. Some of those gears can be difficult to find.

The service and parts manual do a fair job of listing the different trans gears and Speedo drive gears. Be warned, the parts manual is somewhat difficult to follow. It covers all of the dual carb twins for 64/65 along with the Thunderbolt Rocket which was a single carb model and is closer to an A65 Rocket than a Lightning Rocket. Then add in all of the changes that occurred to the dual carb twins in that short time frame makes a difficult to read parts book.


Never underestimate the human ability to elevate stupid to a whole new level!.
DAMadd #894412 10/30/22 7:31 pm
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Also I picked the bike with the ultra rare headlight shell that of course is nowhere to be found. And no fuel tank, maybe I'll go clubman replica with it..


Dave
65 TR6R 68A65T 69 B44VS. 74 T150V 65 A65 D L/R
19 Chieftain
DAMadd #894434 10/31/22 12:07 am
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I have a tank that I may let go. I want to reduce inventory. Also have one of those headlight buckets, but for a T/R or base Rocket. it has a cutout for a speedo.


Never underestimate the human ability to elevate stupid to a whole new level!.
DAMadd #894447 10/31/22 3:00 am
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Appreciate the feedback. Gonna scrounge hard for the headlight, bike has speedo and tach, and I'm comfortable trying to keep them operating, key word
Trying
But if you have a tank pm me the details. Everything is a balance between what to keep and what to let go, but hoarders have hurt the British scene. Percieved value vs actual all that. I just love bringing machines back from the dead, that my real hobby.

Soapbox over

Last edited by DAMadd; 10/31/22 3:13 am.

Dave
65 TR6R 68A65T 69 B44VS. 74 T150V 65 A65 D L/R
19 Chieftain
DAMadd #894500 10/31/22 7:17 pm
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Also this
[Linked Image from i.postimg.cc]

Over by the clutch operating arm
I'd imagine that's some kind of gear ratio or related


Dave
65 TR6R 68A65T 69 B44VS. 74 T150V 65 A65 D L/R
19 Chieftain
DAMadd #894501 10/31/22 7:45 pm
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Speedo gear ratio tag.


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DAMadd #894502 10/31/22 7:49 pm
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Yep. It's actually a production line trick. Because machines had 18 and 19 inch wheels, they had 17, 18, 19, etc front sprocket teeth, rear sprocket variables too, BSA had to have a system of pairing Smiths speedos correctly. The numbers 7/11 for, e.g. or what have you, indicate the particular pair of gears you have (Or should have), fitted at the end of the layshaft, and in the inner timing cover that drive the speedo. The original BSA workshop manual has a list of the gears fitted to each model that produced. Someone here no doubt can produce an image of the list.

Last edited by wbabojo; 10/31/22 7:53 pm.

Gavin
You can't make a silk purse from a sow's ear.
DAMadd #894535 11/01/22 3:06 am
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No one yet mentioned that '65 was the last year of the drive-side ball bearing main. I have a '65 LR lower in my bitsa now, and I've been pleased with the results. The ball bearing controls axial load whereas the later roller bearing does not. However, the roller bearing handles more radial load. The conventional wisdom is that the ball bearing sufficiently handles the radial load of "normal" street use in a stock engine.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
2007 Triumph Bonneville Black
DAMadd #894564 11/01/22 1:17 pm
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And the '65 was the last year for the narrow crank.


1967 BSA Wasp
1967 BSA Hornet (West Coast Model)
1967 BSA Hornet (East Coast Model)
1968 BSA Firebird Scrambler
1968 BSA Spitfire Mark IV
1965 BSA Cyclone Competition Build
1965 BSA Spitfire Hornet Build
DAMadd #894588 11/01/22 6:46 pm
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Tag reads 7/10 and bike has a later style ( like my 68 tbolt) 18" qd wheel with speedo drive.

Is narrow crank better?
One good thing is it has a tankful of oil that's not dripping out of anywhere on to the floor and when I depress the Kickstarter the tach drive turns so the oil pump is turning too. Have to finish assembling the t150 before I can get this up on the bench and really dig in, but I cleaned the grime off and gave it a little wd40 love
[Linked Image from i.postimg.cc]

Last edited by DAMadd; 11/01/22 6:49 pm.

Dave
65 TR6R 68A65T 69 B44VS. 74 T150V 65 A65 D L/R
19 Chieftain
DAMadd #894593 11/01/22 8:37 pm
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Originally Posted by DAMadd
Is narrow crank better?
Narrow crank also means narrow case, so it will only accept the ball bearing drive side. (not a huge deal, as mentioned above)
Later cases and cranks provide the option of using a roller + thrust washer or ball bearing.

So, the narrow crank limits what parts you can throw at it, more than the later motors do.

DAMadd #894599 11/01/22 10:18 pm
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DA: I have a 1965 A65C engined Thunderbolt/Rocket that I have had for more than 50 years. When I first got it I opened up the engine to clean it out and replaced the drive side ball bearing on spec but left the timing side crank bushing alone as It looked very good with little wear.

Over the years since then I have added a Boyer ignition, a Podtronics regulator, converted to 12 volts, replaced the pistons, valves and guides but have not opened up the cases again. The oil pump was replaced with an SRM version to reduce the wet sumping and I installed a return line canister type oil filter.

It has been a very reliable machine.

Gordo


The roadside repairs make for the best post ride stories.
DAMadd #894637 11/02/22 11:49 am
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Good to know. I'm amazed it turns over. Still has the unincapsulated stator. Not sure what year BSA went to 12 volt. I'll be going some form of modern ei and a regulator. Really tempted to get it set up and start it before a complete teardown tho its probably not in it's best interest sludge trap-wise. But I have and old b44 tank I could throw on....


Dave
65 TR6R 68A65T 69 B44VS. 74 T150V 65 A65 D L/R
19 Chieftain
DAMadd #894641 11/02/22 3:05 pm
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I would think a machine with no history should not be fired up without some investigation.

For example I bought a complete T100 engine with no history and when I took it apart I found the left side big end journal had a slightly distressed look. The right side looked fine. Further examination discovered that the oil passage to that side was virtually plugged up with hardened crap. A start up would not have been kind on the crank.

Gordo


The roadside repairs make for the best post ride stories.
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MarcB #894683 11/03/22 1:23 pm
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Originally Posted by MarcB
Originally Posted by DAMadd
Is narrow crank better?
Narrow crank also means narrow case, so it will only accept the ball bearing drive side. (not a huge deal, as mentioned above)
Later cases and cranks provide the option of using a roller + thrust washer or ball bearing.

So, the narrow crank limits what parts you can throw at it, more than the later motors do.

The narrow crank in narrow cases part is correct but holds no corrolation to what bearing type is used, apart from they both changed at the same time. My 68 engine with the wider cases and wider crank is fitted with the ball bearing on the drive side, needle roller on the timing side (RNA4907, not the NKIB5907 combination bearing) and has run lovely for the last 7 years like this.


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)

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Originally Posted by Allan G
The narrow crank in narrow cases part is correct but holds no corrolation to what bearing type is used, apart from they both changed at the same time.
Try fitting a thrust washer on a narrow crank/case and you'll see what I'm referring to. You can fit a roller bearing on the narrow crank but, without the thrust washer, your bush won't last.

That why I pointed out that the later case/crank allows the use of either bearing types, but the narrow ones do not.

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When I get in there I suppose I'll see what's what. Looks like it was scramble raced although there's only a tiny ding and scrape on the primary and the frame tab for the left passenger peg/ exhaust mount is a little tweaked. 245 on the clock but it was not connected. Also a reddish brown leather seat cover in great shape but of questionable fashion appeal. Only 1 open header. Considering doing a clubman replica since I have a set of ace bars late of the t150 all the other tin is unusable ( except as an off road bike) and no covers so a blank slate with a 650 motor


Dave
65 TR6R 68A65T 69 B44VS. 74 T150V 65 A65 D L/R
19 Chieftain
MarcB #894739 11/04/22 4:29 pm
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Originally Posted by MarcB
Originally Posted by Allan G
The narrow crank in narrow cases part is correct but holds no corrolation to what bearing type is used, apart from they both changed at the same time.
Try fitting a thrust washer on a narrow crank/case and you'll see what I'm referring to. You can fit a roller bearing on the narrow crank but, without the thrust washer, your bush won't last.

That why I pointed out that the later case/crank allows the use of either bearing types, but the narrow ones do not.


Appologies Marc, I had only half read what you had written (despite quoting the whole piece), chasing my tail somewhat at present and head is a little rattled. My small brain had read it as "much as saying you can't use the ball bearing on a late motor" - which you did not say at all crazy


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)

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