Oddball engines and prototypes

[J.A.W.]

Funnily enough, H-D picked up the ex-Commando isolastic system, & still uses it.. to good effect..
& ironically, the current 'Commando' uses both a balance shaft & off-set crank to try & quell its vibes..

The porky current Bonnie uses a similar set-up & yeah, its still tuned slower than a decently crisp old-school Commando..

[WilDun]

Funnily enough, H-D picked up the ex-Commando isolastic system, & still uses it.. to good effect..
& ironically, the current 'Commando' uses both a balance shaft & off-set crank to try & quell its vibes..

The porky current Bonnie uses a similar set-up & yeah, its still tuned slower than a decently crisp old-school Commando..

That's a shame that a V twin especially one with the cylinders in line with each other (via a forked rod) needs an Isolastic system, considering that a V engine can be set up in such a way that it can be quite smooth (vibration wise) - but that's all sacrificed in the search for a certain look (ie a narrow V).
Being interested in aircraft, I was following a story of a guy in the states who was constructing a homebuilt, intending to power it with a Harley engine, unfortunately when it came the time to fire it up, the whole project ground to a halt because of vibration!

Having said all that, a modern Harley is not a bad looking machine, but many of those who ride them are not doing it because they like bikes in general - they are riding them because they have a need to be part of a group, with all the frills and dressing up that goes with it.

Also, let's face it, as HUSA says, the big parallel twin as we knew it was a pre-war design and is about the worst layout you could have for vibration, (ie except for my old Beeza B33 single) -it used to leave my arms and hands with no feeling at all on a long trip!

BTW, contrary to what most Americans would think, Messers Harley & Davidson were both English!

[J.A.W.]

Sure were W-D, & Triumph was established by Germans..
To be fair, Turner's pre-war Triumph Speedtwin was a most economical & compact way of increasing
the valve & piston area of a 500, for performance, even if its 360` crank meant it was not much better than a single for vibes..

It was really only when Norton pumped their post-war twin up to 750cc in the `60s ( for the Yanks) that the isolastic
system was really needed, & it made a success of the Commando, which IMO, remains the epitome of a classy sporty
old school Brit-bike, mechanical nightmare or no..

[WilDun]

Sure were W-D, & Triumph was established by Germans..
To be fair, Turner's pre-war Triumph Speedtwin was a most economical & compact way of increasing
the valve & piston area of a 500, for performance, even if its 360` crank meant it was not much better than a single for vibes..

It was really only when Norton pumped their post-war twin up to 750cc in the `60s ( for the Yanks) that the isolastic
system was really needed, & it made a success of the Commando, which IMO, remains the epitome of a classy sporty
old school Brit-bike, mechanical nightmare or no..

Yes, all true - I never really had a chance to compare the Commando frame to the Featherbed, but I must say that the Featherbed was a joy to ride.
I seem to remember that the guy who was called in to rescue Norton from the decline and got the Commando started, wasn't even a motorcycle designer and he was horrified that the Featherbed had so many curved tubes and set about consigning it to the scrapheap, when to be honest it would have done a sterling job (maybe modified here and there) for a lot more years.
Now , however it is dawning on people that curved tubes are actually very strong and huge "backbone" tubes also have resonance problems.
A good example of the large diameter backbone frames was the 250 and 350 Aermacchi - great little production racers but i have seen them twitch almost uncontrollably on the odd occasion!
A lot of people of course will swear by the Commando and no doubt it was a lot of fun, but really it was born in order to prolong the days of a (sadly) outdated engine.
........Still,who knows, even I might be wrong!

[J.A.W.]

Poor ol' AMC (Norton-Villiers by then) had bugger all, & it was the Commando frame, housing the only
near-competitive engine thay had, that saved 'em - for nearly a decade, anyhow..

Yanks wanted power, & some comfort too - the Atlas was too coarse, but the light Commando gave
a smooth ride where it mattered, & was quick enough to be a competitive 'superbike' - back then..

A bunch of rubber donuts holding the drive-train apart from the chassis shouldn't have worked,
& poorly set-up Commandos can be awful/frightening, but a properly sorted isolastic is surprisingly good..

[husaberg]

Poor ol' AMC (Norton-Villiers by then) had bugger all, & it was the Commando frame, housing the only
near-competitive engine thay had, that saved 'em - for nearly a decade, anyhow..

Yanks wanted power, & some comfort too - the Atlas was too coarse, but the light Commando gave
a smooth ride where it mattered, & was quick enough to be a competitive 'superbike' - back then..

A bunch of rubber donuts holding the drive-train apart from the chassis shouldn't have worked,
& poorly set-up Commandos can be awful/frightening, but a properly sorted isolastic is surprisingly good..

Triumph/BSA had the Rocket 3/Trident it was a better engine.
Hele as a stop gap wanted to do the Quantrant 1000/4.

He had drawn up a modular series of engines all based around an ohc design the culminated in a 1000cc V5.

Not totally sure but the Commando was an overgrown AJS Stormer frame which I think is a Ken Sprayson original design (Ken was Reynolds Tubes guy)
Pretty sure the commando frames were originally built in the Reynolds factory as Norton had no welding facilities. Same reason as the featherbed.

No offence, but other than the mildly interesting fastback I always fount the Commando to be ugly.
It was only to be a stop gap until the Cosworth P motor was ready.
The isolastics were designed by Hele he actually had the patent in his own name.
The poms had the designs and designers but the management would not invest in toolng for the factories.

look at the Fury/Bandit that they actually started making them. They were told to stop.

[J.A.W.]

Dunno if it was all Doug Hele's doing.. Hooper, Hopwood, Bauer, Trigg et al. were all in on it..

As for the Trident/Rocket 3 being "better", sure its more powerful.. but its a big lump,
& as an example of a Brit 'nuts & bolts' mill, its a real mechanical 'dogs breakfast'..

The Bandit/Fury & Cosworth were another couple of sadly/typically British 1/2 arsed examples of 'failure snatched from the jaws of victory'.

[husaberg]

Dunno if it was all Doug Hele's doing.. Hooper, Hopwood, Bauer, Trigg et al. were all in on it..

As for the Trident/Rocket 3 being "better", sure its more powerful.. but its a big lump,
& as an example of a Brit 'nuts & bolts' mill, its a real mechanical 'dogs breakfast'..

It was also smoother bigger newer and had a bigger CC potential.
I read the Vetter x75 story the other day it was funny. The bike was never meant to have those long chopper front forks Bsa Triumph got the measurement f-ed up.

[J.A.W.]

Well, dunno H, if you look at the original prototype BSA Hurricane, it does have extension slugs in the stanchions..

Commando was a usually smoother machine to ride, from a riders perspective, even if the mill was dancing in rubber..

[husaberg]

Well, dunno H, if you look at the original prototype BSA Hurricane, it does have extension slugs in the stanchions..

Yes it does but the forks he used were short ceriani's so he made the inserts.to get them to Std Length
Then when BSA Triumph did it they added the extra length to already longer forks.
look at the rake on the prototype.It was no Chopper


This is what they sold. Vetter was actually a road race guy. it was meant to look light and modern.

[J.A.W.]

Ok, ta for the heads up there H,

The BSA guys had probably been watching 'Easy Rider' while tripping their tits off anyhow, so figured the chopper-look was in..

[husaberg]

Ok, ta for the heads up there H,

The BSA guys had probably been watching 'Easy Rider' while tripping their tits off anyhow, so figured the chopper-look was in..

Funny enough the Japanese made the same mistake in the 90's they got the drawing f-ed up and made the frame spars 2 inches too long pretty sure it was for Suzuki on a frame for Kevin.
Yamaha cocked up one in the 90's and had crushed all there old frames so had to go get some from ROC which was an exact copy of the design they had crushed.

[WilDun]

Seems to me that all the designers and engineers at Norton and Triumph had the will to look ahead, the management didn't want to know, but I guess they had all the problems associated with trying to stave off the Japanese and having the cost of doing some (very fast) development work both in marketing and innovative engineering, to be able to hang on. - all history now but valuable lessons learnt for any future assault on the market.

Geez, I can't keep up with these posts!

[J.A.W.]

Yamaha had a strange Brit-fetish back then too..

XS 650 was an attempt at a better BSA Lightning; TX 750 a Commando ( with dreaded oil-frothing balancer shafts instead of isos);
TX 500/Triumph Daytona; XS 750/Triumph Trident; TT/SR500 & BSA B50; XS 1100/Quadrant; & they even tried a Vincent V-twin copy..

& about 1/2 of them., were worse than the Brit equivalents..

[husaberg]

I read an article about Edward Turners chauffeur .
He was very honest about what an arrogant ass Turner was what I never knew was Turner was a very larger shareholder in Triumph. 10-or 20%.
He said he was probably the closest thing to a friend turner had and even he didn't like him.
The management were all more interested in board room manoeuvring and its politics than making bikes.
Funny thing was Turner came back from a trip to japan in the fifties and remarked to him words to this effect
Gee lad if we don't sort ourselves out we won't be making bikes in 25 years time.
Soon afterwards he order a new Jag or similar on the companies behalf.
Turner never did details Arthur Wicks used to do that for him. Plus he hated racing and wouldn't let them go racing for publicity.