Hi all,
As has generally been pointed out, a 180’ twin is not a nicely balanced engine, the two piston working as a rocking couple. Not a nice vibration with bigger engines. In my last year of school I had a Yamaha TX 500 with a two into one hooker exhaust that went like stink. It was very complex with 2 counter rotating balance shafts and twin cam 4 valve head. I just read the review in the previous post of the Yamaha XS 750 and my bike had all the same problems including balance shafts coming out of phase and trouble with the starter sprag clutch. However it was beautifully smooth to ride. It would eat my mate’s 500/4 and wasn’t far behind the big two strokes of the day.
So I guess that the 360’ twins the British used served them quite well up to a point. When built down to a price, of smaller capacity and with lower compression, they were ideal, especially when compared to hammering around on a big single. Obviously by the sixties the writing was on the wall but none are as blind as those who will not see, so british management refused to capitalise into new tooling to make their bikes competitive into the future.
I believe that so good was the skill of the famous engineers (i won’t bother naming them) that they were able to keep tweeking the outdated design and kept them competitive long after their use by date. I wonder if this actually worked to the companys’ disadvantage, as by the time it was clear to everyone that the bikes were outdated it was too bigger leap to catch up with the predominately Japanese opposition.
I am an unashamedly big Trident fan (and Norton of course) but in quiet moments of reflection I have to admit they were too little, too late. Done right with new tooling, more capital and done a few years earlier……but that’s another story
The previous post also and a write up on the little CB175. I also had one. What a little gem! One wonders what the leaders of Triumph Norton BSA etc must have secretly thought when they rode one. Surely they must have known the writing was on the wall.
So, in brief, I think I’m saying a well designed 360’ vertical twin is a hell of a good package with all sorts of advantages when strapped into a good frame. However, it ultimately is not possible to make strawberry jam out of horse excrement. Ultimately they were not capable of keeping British bikes at the forefront of world biking.
As a final aside, am right in thinking that Bonneville, in their last gasps in the eighties, made a version with harmonic balance shafts? A mate of mine had a well sorted T140V with an eight valve Norish head. It went like crazy and had acceptable vibration. Such a shame the TSS wasn’t done earlier and better.
regards
alan
