Evolution plays a role in all things and it has in Motorcycling
Evolution plays a role in all things and it has in motorcycling. We the keepers of old motorcycles would know more than most when it comes to the old clunkers in our shed. I am sure that a fair chunk of modern motorcyclists think motorcycles started in 1985 or thereabouts, kidding, sort of. In 1988 I dropped in on a friend’s BBQ and he had a mate who was an “outlaw” visiting. This future brain surgeon ( sorry Bruce) could not believe that I would be so game as to ride a motorcycle with a cable operated braking system unlike his Highly Wobbler with a pretty puny hydraulic system.
Anyway this is about frames. Specifically Triumph frames and in particular post war swingarm up to 1983. The first swingarm model of 1954 was a mild step up from the ridgid and in fact if a sidecar was to be attached a ridgid is a better choice, I think , from experience. Now this new frame had the swingarm attached via a cast lug on the single rear downtube. There was no mounting points further out to stop the downtube twisting due to side loading. This would obviously be exaggerated with a chair attached.. Although a marked improvement over a ridgid hopping about over bumps, these first frames were known to be lively in the handling department if you were a hard charger. The next incarnation was ’60-62 and again the factory saw fit to continue with the cast lug, same swing arm and no other visible means of support out wide. It did have twin front down tubes and was a good looking thing but was still in the lively category . I have built and ridden ,many of both of these types over the years and done many miles. The factory then moved on a bit and basically took the rear section of that pre-unit duplex and made a new single down tube front section, as a matter of fact they can be interchanged, I have an 850cc special in the shed using a duplex front section with part of a ’65 rear section. This 1963 -70 single front down tube frame had a different cast lug on the back down tube with wide supports connected to the rear engine plates . Some of the lively was taken care of, all 3 of these frames won races so I am not saying they are no good or anything like that, a good rider can ride around lots of problems on the track that people like me would never know existed. Now I did have a 1961 trophy that was a bit twisted in the swingarm and it had some odd handling traits. But I rode it thousands of miles like that, including 2 trips to Lightning Ridge, in the wet.
Proof that better frames existed in the pre-unit days is the fact Tritons and Tribsas came into the mix. Taking a very tuneable Triumph engine of the day and transplanting it into the famous Norton featherbed was a popular and rewarding thing. The A10-B33 swingarm frame is equally as good and a whole lot less money. Proof of their capability is that the Goldstar engine lived in these BSA frames. Both are still popular today. Pre-unit triumphs are my fave and I like them just as much if they are in their original frame or not. Things were on the up in Triumphs evolution and the new unified engine was cast in one, making the engine /gearbox a ridgid construction. It doesn’t look as good as the pre-unit, I think and I also think the less ridgid pre-unit models were smoother, being a bit more loosey goosey. Tech term. All the way from the 1950 650cc Thunderbird to the last 750 of 1983 sees most of the engine and gearbox internals interchangeable. I have done it all, retro fitting later cranks, top ends , 5 speed gearboxes all the way back. A good deal I reckon . Bit like the H-D evo. First year was not much more than a shovel head engine with a new top end.
So any way ,we come to 1971 and the Oil in Frames. This was basically a copy of the Ray Hensley designed Trackmaster dirt track frame. A killer frame and carving up the 70’s era dirt tracks in the US. A friend of mine got the very last Hensley made frame before Ray died of cancer. People just don’t seem to like oil in frame models, I think they are the best thing Triumph ever produced in the way of frames. By the time this frame came around the motor was hopelessly out gunned so it never shined. Now days with historic racing particularly in the US it is a rare sight in deed to see pre OIF Triumphs on the track in classes where this OIFrame is legal. I have a number of specials based on this frame and they were worth nothing at swaps. Another good deal for me. It is a fully welded ( no cast lug hinges ) full cradle with a huge oil bearing backbone. Stiffer than a stiff thing.
A couple of instances I witnessed to back this up are, a mate Terry Scoggins ,a very handy winning rider in WERA on the east coast had me help build a Trident in an Oil frame. I had already done it here, he was keen to try. Anyway he reckons it to be the best handling frame he had ridden. He had only ridden Bevel and rubber band Cagiva/Dukes until then. He then got hold of a Nourish 8 valve Triumph Rob North framed special. A beautiful thing. After throwing it away twice he went back to the OIF Trident for a while before going back to a Cagiva. I have that OIF Trident in my shed. It was a bit too much maintenance for him. Another friend , Pat Mooney was riding OIF twins when I met him. He had won a couple of AHRMA sportsman 750 titles and then got a new Rickman chassis. Before that season was out he had gone back to the OIF frame before moving to 500Premier on a Manx. A multi time AHRMA champion. Pat also crashed a Rockett Racing 69 Triumph when the swingarm pivot bolt sheared, something the larger OIF s’arm pin won’t do. I have seen it another time and the Nortons use this same size 9/16 shaft for the rear wheel and I’ve seen a broken one and many bent ones, on Nortons, right where the thread meets the plain part of the shaft.
It is a shame the media were down on something a little different back then, I know the first 5 speed gearboxes had a poor record ,but the problem was soon fixed and they are a delight, a very modern feel. The disc brakes from 73 on are great albeit a bit dumbed down but they can be made more effective with a reduction in the mastercyclinder bore size. The all round ride ability makes the OIF era machines a good choice for classic riding.
I have a 650cc September 1974 bonnie with near 50,000 miles that Jude and I put on it . Still on the original bore, pistons, valves and rod bearings, although it’s getting a bit smokey. It got a new Hi capacity T/Side ball main bearing, valve guides and rings at 12,500 miles. It has been a beauty , it has one of the “weaker” 5 speeds and is geared to cruise at 72mph @ 4000rpm. Would still carry the front wheel across an intersection and run all the way to a ton – ton five. The box needed attention once when a bush walked and some loctite fixed that. This is a bike I used a couple of times at Lakeside practice days, ride out run 20 laps and ride home. I fitted a smaller front tyre to get rid of some shaking /weaving coming down the hill onto the straight, a great handling machine. Now I’m not saying that the humble OIFrame is on par with the likes of the Goldie or featherbed Norton but the featherbed was limited to a few uses ie. road , cafe and road race use mostly. The Goldie/A10 and later A65 variant on the other hand have been used in everything from trials, enduro, mx , road touring , cafe, road race, dirt track and so on. I have seen BSA and Triumph OIFrames used successfully in all these genres as well. A very versatile piece of bent tubing.
You may agree , you may not ,the editors are always looking for filler, so pick up a pen.
So there you go, I think Triumph saved the best for last. Or was it just evolution.