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No difference as lead in fuel isn’t a combustion improver.


Now let’s all have a beer beerchug

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

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Nick, a BICYCLE can go fast enough to "get you killed," so what's your point?

And, yes, the problem here in the 'states was often a NEGLECT of maintenance.
As BSAs were less expensive here than Triumphs, cheapskates tended to buy BSAs, rode them HARD
(i.e.: ABUSED them) and didn't bother to change oil on schedule, or not at all.

Dirty oil wore out the timing side crank bush, which also feeds oil to the crank, and not enough lubrication entered the crank. Result of this is failure of the left-side con rod.

Personally, I have ridden A65s and B44s, and like them. The A65 frames were further development of the Gold Star frames, and handle very well. The B44 is very sure-footed on dirt and gravel roads, they do not "hunt" on gravel roads like my Triumphs do, which is an irritating characteristic of my '72 T100R.

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Originally Posted by NickL

As for the a65 frame it handles well but it's damn heavy. Whereas the late goldie frames were 531 and light.


You learn something every day! I never knew that.


Current: 2 x 1966 A65S, 1 x 1967 A65SA, 1 x 69/70? A65LA space Y, 1 X D14/4 & 1 x B175
Past: 4 x 1976 T160V, 1 74/5 T150V, 83 model GSX 750 ESD, Z650, Katana 1100(Bathurst Model), 79 T140V, 70's TR6, 2 x 1971 BSA 250 Gold Stars, 50's 350 Goldie, A65 Spitfire semi basket case, 1965/6? A65 LC, Tiger 21 350 & a D14/4 Bantam, 175 Bridgestone Twin with Zimmerman discs!
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I believe the closest thing to it is T45, which is what a lot of competition frames use now. Bloody expensive stuff but I bought enough of it to modify an A65 frame and make a bantam trials subframe. With probably some of the larger size left... I believe it’s also a pig to weld.

Gave me an idea hmmm. Thanks Nick :bigt


Now let’s all have a beer beerchug

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

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Did you know that one of the engineers responsible for the engine that was used in the pre-production photo shoot for the oil in frame '71 Firebird said that the cylinder head had been machined ‘’to drawing’’, something that Small Heath had never done to any of its production bikes.

Run on a dynamometer prior to release, the engine had recorded a peak output of around 8bhp more than the production motors.

Acceleration was reported as better and it was very tractable.


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Originally Posted by NickL
My outfit was T45, all sifbronzed. Proper gas bronze welding not that electric rubbish.
The 'Lowboy' frames were originally 531 but then went to T45.
T45 is a lot different to 531 but easier to use and more available. You can MIG and TIG T45 not 531.

The 531 goldie was a factory option not standard, i am told. Sorry, i jumped the gun there.


Don’t think there is anything wrong with TIG, infact it’s not that far removed from gas welding in a way. Saying that I have gas welded and I have never tig’d. I can mig weld though and can do a good job too. I think it’s SIG32 with argon gas for T45 on a MIG, I have the wire but it’s like 2 years since I looked at the box with the wire in and probably got the name wrong laughing


Now let’s all have a beer beerchug

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

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For the sake of us non-metallurgists, do T45 and 531 have common names? Does my A65 frame steel, which I know of only as "mild steel", have a numerical name?



Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
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Originally Posted by Mark Z
For the sake of us non-metallurgists, do T45 and 531 have common names? Does my A65 frame steel, which I know of only as "mild steel", have a numerical name?


No.
The whole idea of the numbering system was the get rid of all the proprietary names.
Plain carbon steels ( mild steel ) are generally referred to by their carbon content.


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Wiki helps. Most production like frames were simple old mild steel.


"531 tubing became the tubing-of-choice for most framebuilders at least partly because of the huge range of butting, diameters and thicknesses of tubes along with different stays and fork blades available - helped by the willingness of Reynolds to make special tubes for certain manufacturers. Reynolds also made up complete 'sets' of tubing for different cycling applications - for example 531c (Competition), 531st (Special Tourist), 531ATB (All Terrain Bike) and so-on. This flexibility made 531 still competitive even after the introduction of more advanced alloys. The widespread use of TIG and MIG welding in cycle manufacture became a problem as 531 reacted poorly to the higher temperatures produced and 531 has been gradually phased out as a result.[2]

The most common like-for-like replacements for 531 are Reynolds 520 and 525 - a Chrome-Molybdenum tubing with very similar characteristics, but in addition to brazing, can also be welded. The 520 tubing can often be seen on modern "fixie" bikes (urban "track" type bike frames), while the 525 with its thicker-walled seat stays is more for cyclo-cross and touring framesets.

The approximate alloying composition of 531 tubing is 1.5% Mn, 0.25% Mo, 0.35% C, and is similar to the old British BS970 En 16/18 steel (EN 16 is similar to grade BS970 605M36). Its mechanical properties and response to heat treatment are broadly similar to the AISI 4130 standard alloy steel, also used for bicycle frames, motorcycles, as well as aviation and motor-sport.[3] This material was used to form the front subframes on the Jaguar E-Type of the 1960s.[4]

Reynolds 531 is now only available to special order.[3] The nearest available stock material is BS4t45 to Bs5T100 in accordance with BS6S100 conditions.[5] (T45)"


71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
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Reynolds were based in Birmingham and were part of the Tube Investments (TI) engineering group--a major company in British engineering in the post war years.
Reynolds (tubing) should not be confused with Renolds (chains). No connection.
Reynolds were very active in the bike racing scene.
One of their guys went around all the Grand Prix races giving advice and welding up broken/ cracked frames etc.
"In the day" the tubing to use in racing bikes was 531--with T45 its OK but not quite so good relative.
As Nick says the best way to join 531 was sifbronzing.
This gave the joint a bit of flex and reduced the chance of cracking.
If you want a good read then get a book called "The Frame Man" by Ken Sprayson.
Ken was the guy I mentioned earlier who worked for Reynolds and travelled with the Grand Prix circus.
HTH

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Isn’t T45 used in aircraft production? confused Sounds like it’s perfectly viable to me if it is. It’s also used in many motorcross or other special frames.


Now let’s all have a beer beerchug

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

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Thanks; sometimes it's helpful to learn just how much I don't know about something.


Mark Z

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Originally Posted by Allan G
Maybe they meant Kilometers wink

Had 110mph out of the lightning, and there was a little more in the throttle but at the time the suspension wasn't up to even that so it was quite hair raising. That said, the bike isn't standard.. Megacycle track cam (x12) 32mm Concentrics, small port head with big valves, and my own style 2-1 (short pipe) with long dunstall silencer. Could probably get more by adjusting the cam timing and tweeking jetting further. But im pretty happy with what I have their as a road bike.

also sheading some weight from my ever growing fat ass will help laughing

When I first put my Lightning back on the road I remember opening it up once and seeing around 110 on the speedo. It was so hard to ride like that that it didn't last long. The wind speed was trying to pull me of the handlebars and I can distinctly remember hardly being able to keep my feet on the footrests because everything was vibrating so much. The madness was cut short when my right foot vibrated onto the gear lever and managed to slip the bike into a false neutral. For a split second I thought the engine was going to explode and come through my arse. I calmed it down a lot after that.

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I've probably run my Thunderbolt up to 80 or so, it wasn't particularly enjoyable! Fastest I have been on 2 wheels was 95 mph on a brand new 1980 Harley Davidson Sturgis. High speeds have no allure for me on 2 wheels.


1970 Lightning
1968 Thunderbolt
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Fastest I've been on my B31 with iron head and barrel 81.4745mph standing start 1 mile
Fastest I've been on any bike, (ZZR1400) 194.707mph standing start 1 mile

Last edited by Andy Higham; 09/28/20 6:57 pm.

BSA B31 500 "Stargazer"
Greeves 200 "Blue Meanie"
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GM500 sprint/LSR bike "Deofol"
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That’s a mad crazy speed Andy!

With the B31, did you ever go flat out for further than the mile? Even at 81.4 mph that’s some going for a B31, the best I’ve ever known one to do was just over 70 in standard form. Although weren’t their 350 Goldie siblings supposed to do around the ton?


Now let’s all have a beer beerchug

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

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my 66 Tbolt will do 70 mph on a flat, 75 with a long downhill.

very easy to start-- almost no compression to fight!


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Originally Posted by kevin
my 66 Tbolt will do 70 mph on a flat, 75 with a long downhill.

very easy to start-- almost no compression to fight!

Is there a sidecar on it?


Amateur Loctite enthusiast.
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After 45 years of riding with no gauges, I installed a GPS speedometer, so I can finally gauge my speed with some accuracy. After riding with the GPS speedo for a while, I've learned that I'm not going as fast as I thought I was. So here's where it's at, noting that I'm running with 20-47 gearing, Mikuni VM32 carburetors, Boyer analog ignition, and a single dual-output coil. Also, the crank was dynamically balanced on the last rebuild.

Compared to the pre-balanced days, vibration is no longer an impediment to speed. I took a 200-mile ride this Saturday past, and I did not suffer any numbness in my fingers or my arse. Nevertheless, I'm finding that the engine is happiest at 55-65 mph. And I find I can accelerate lightly from 40 mph in fourth gear, as long as I'm not climbing a grade. The engine does not feel like it's lugging and it never pinks.

Here's the thing, though; at that 60 mph, I'm right around 3/8 throttle. If I twist it past halfway at that speed, the engine comes on like a monster, and keeps accelerating until I get scared and back off, which is about 80 mph. The vibration does not increase over this range. How fast will the bike go? I don't know and I really don't care to find out.


Mark Z

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Originally Posted by triton thrasher
Originally Posted by kevin
my 66 Tbolt will do 70 mph on a flat, 75 with a long downhill.

very easy to start-- almost no compression to fight!

Is there a sidecar on it?


no, mores the pity.

that was the original plan


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The photo-reconnaissance spitfires were the fastest overall, well over 400mph in most cases.

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Good one Nick

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they were the most beautiful of the fighters too, in my opinion.



high performance machines like that attract crazy people to pilot them.


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Awesome video.

Not to be outdone by other posters, my skateboard will do 45 MPH downhill and 50 MPH when I have a beer in my hand.


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 Cyclone Competition Build
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ok i'll bite..i have a gun tunnel plug off a MK1 Spit PR that went down near Folkstone my 1939 Farmall F30 tractor has a top speed of 4 1/2MPH I aint no robot


1972 Triumph T120
1968 BSA A65
1968 MGB Roadster
1979 Chevrolet Camaro Berlinetta
1969 Honda Mini Trail
1939 farmall f30 tractor
2004 Honda Shadow Aero
1972 BSA Thunderbolt
1975 yamaha xs650b
1972 Norton commando
2 olive drab WWII military bicycle replicas
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