anyone got experience with commando engine in wideline frame with isolastics? if so any photos

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Whether or not lighter weight internal do dahs ‘completely eliminate the need for isos’ depends on how smooth you want it to be.

There will definitely still be vibes that would not sit well with those expecting modern bike smoothness.

But they do definitely reduce the overall vibes significantly. JS has a lot of info ref balancing on his web site.

I have JS lightweight pistons and rods in my 920, statically balanced to his suggestions, I set my isos up by nipping them up tight, and then backing them off until I can ‘pry’ the cradle and see comfortable movement. Even like this it’s still MUCH smoother than it was stock with sloppy iso gaps.
 
grandpaul said:
How could you know that?

I have built 17 bikes from SCRATCH, 3 of those were Tritons.

Not a SINGLE one of those was built by first disassembling a donor bike (not disassembled by me, anyway)
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How many face-to-face doubles?

Tritons came into being when Manx engines were robbed to make small race cars. Triumph owners knew Norton chassis were way ahead of Mr, Turner's spindly bolt-ups, and swapped their engines in. No more Tritons should exist than that. Most that do are results of parting out viable machines, which is more profitable than selling them whole. Not parted out by you.
 
Danno said:
How many face-to-face doubles?

Tritons came into being when Manx engines were robbed to make small race cars. Triumph owners knew Norton chassis were way ahead of Mr, Turner's spindly bolt-ups, and swapped their engines in. No more Tritons should exist than that. Most that do are results of parting out viable machines, which is more profitable than selling them whole. Not parted out by you.
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I know the Triton history, have known since the early 70s. Also know Triumph chassis history. If you believe no Norton engines ever blew up or clapped out without destroying their frames, I'm fairly sure you have a mistaken belief on that topic. I've seen rows and stacks of Triumph unit twins in at least three places, all removed from wrecked bikes, so that half of your mistaken assumption is also out the window.

I have owned 171 bikes, many started their life with me as basket cases. NOT ONE was ever parted out that didn't get to rolling stage starting from odd parts; of the TWO that did, one was because I already had two Tritons, so I sold the third frame for a tidy profit, the other was not a featherbed and a guy just wanted the engine from the already bodged (not by me) frame.

I never even hinted that I'd ever built a siamese/double engine bike. Never really had the urge to do so, and lack the equipment and skills anyway.

That only a certain number of Tritons "should" exist, is perhaps the most odd statement I've ever heard in over 50 years in motorcycling...
 
Atlas Commando said:
As a young man with no mechanical ability and virtually no funds, I acquired a Norton Atlas with a cratered motor and a Commando that had been wrapped around a tree. I drilled 3 extra holes in the back of the Commando primary to get the Commando engine to sit upright, and then just bolted things together. I wish I could recall what I did for a top motor mount, maybe stock Atlas? As expected, the thing was 'thrilling' but it was a buzzing anvil. Tail light bulbs were good for a few hundred miles, and soldered wire connections not much better. I sat the oil tank on a piece of inner tube and it held up, but the gas tank developed a habit of cracking at the seams. If I really rev'd it hard my feet would slide off the pegs. It was a big part of my transportation for about a year, until the Commando engine dropped a rod and holed the cases.
I feel that my Atlas-Commando consolidation doesn't quite measure up to these other efforts.....
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There's a reason why it dropped a rod. . . . You mounted the engine upright, this was fine for the Atlas, but the commando was designed to be mounted forwards, the oil system inside the timming cover was modified to cope with this.
 
Bernhard said:
There's a reason why it dropped a rod. . . . You mounted the engine upright, this was fine for the Atlas, but the commando was designed to be mounted forwards, the oil system inside the timming cover was modified to cope with this.
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That's an interesting observation. I knew nothing of these things back then. It spun, it hauled me down the road, life was good..... at least for about 5,000 miles. I recall checking the oil tank while standing on the side of the road looking at the hole in the cases. It was maybe 1/3 full so I always attributed the failure to personal ineptitude.
 
I admire those of you that have the knowledge to build "outside the box", I do not have that level of talent so I sick to building within the original design/architecture.

For those of you that want to put a isolastictically mounted Commando engine in a featherbed frame with a swingarm that is not attached to the Commando cradle, think about a final drive with a belt...

Best.
 
grandpaul said:
I know the Triton history, have known since the early 70s. Also know Triumph chassis history. If you believe no Norton engines ever blew up or clapped out without destroying their frames, I'm fairly sure you have a mistaken belief on that topic. I've seen rows and stacks of Triumph unit twins in at least three places, all removed from wrecked bikes, so that half of your mistaken assumption is also out the window.

I have owned 171 bikes, many started their life with me as basket cases. NOT ONE was ever parted out that didn't get to rolling stage starting from odd parts; of the TWO that did, one was because I already had two Tritons, so I sold the third frame for a tidy profit, the other was not a featherbed and a guy just wanted the engine from the already bodged (not by me) frame.

I never even hinted that I'd ever built a siamese/double engine bike. Never really had the urge to do so, and lack the equipment and skills anyway.

That only a certain number of Tritons "should" exist, is perhaps the most odd statement I've ever heard in over 50 years in motorcycling...
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Just my opinion and now we have your opinion of my opinion. Never mentioned anything a out blown-up engines, so I'd appreciated not having words put in my mouth. Why anyone would put a clanky Triumph twin in a Norton chassis when Norton motors are available is beyond me. Yes, I have owned Triumphs. I always thought they were reminiscent of stone-age axes compared to a Norton. Don't get your Triumph-branded panties in a knot, it's just my opinion
 
Danno said:
Just my opinion and now we have your opinion of my opinion. Never mentioned anything a out blown-up engines, so I'd appreciated not having words put in my mouth. Why anyone would put a clanky Triumph twin in a Norton chassis when Norton motors are available is beyond me. Yes, I have owned Triumphs. I always thought they were reminiscent of stone-age axes compared to a Norton. Don't get your Triumph-branded panties in a knot, it's just my opinion
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Not trying to put any words into your mouth, but on this side of the pond, used second hand Norton engines were hard to get hold of, Triumph were more common.
 
I think I've posted this elsewhere, but for a contemporary view, the builder of Triton in a '68 magazine article cited his reasons for choosing a Triumph motor over the Norton as the former being lighter, simpler, quieter and with cheaper spares availability.....
 
Danno said:
Why anyone would put a clanky Triumph twin in a Norton chassis when Norton motors are available is beyond me. ... it's just my opinion
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I've never put ANY clanky engines in Norton chassis. I always use very nicely overhauled ones that don't clank the least little bit. More like a whirring, tapping, normal sound VERY MUCH about the level of a similarly overhauled Norton.

I mean, that's just silly, really...
 
Fast Eddie said:
Whether or not lighter weight internal do dahs ‘completely eliminate the need for isos’ depends on how smooth you want it to be.

There will definitely still be vibes that would not sit well with those expecting modern bike smoothness.

But they do definitely reduce the overall vibes significantly. JS has a lot of info ref balancing on his web site.

I have JS lightweight pistons and rods in my 920, statically balanced to his suggestions, I set my isos up by nipping them up tight, and then backing them off until I can ‘pry’ the cradle and see comfortable movement. Even like this it’s still MUCH smoother than it was stock with sloppy iso gaps.
Click to expand...
What is the weight of the lightweight rods?

I'm thinking the stock alloy rods are very light( sorry, I don't have the numbers)
 
worntorn said:
What is the weight of the lightweight rods?

I'm thinking the stock alloy rods are very light( sorry, I don't have the numbers)
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I can’t recall the actual weights, however Carrillo rods are heavier than stock rods, but the JS Carrillo rods are lighter than stock Carrillo rods.

But the main thing is that the combined JS rod / piston package is lighter than stock, and all of that saving is on the piston side of the rod where it makes most difference.
 
worntorn said:
What is the weight of the lightweight rods?

I'm thinking the stock alloy rods are very light( sorry, I don't have the numbers)
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Here's Carrillo light weight rods and JE forged pistons against what was in my Commando at the time (not stock though I believe). The JE piston weight included the cardboard box with the rings in. Both my rods and pistons pairs were different weights to each other but the Carrillo and JE were spot on the same.
Supplied by Jim Shmidt.
The JE piston, gudgeon pin and box with the rings in are 260 gms if you find it difficult to see the scale weight.
 
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No Triton is ever as good as a Manx, and a Norvin is ten times worse than a Triton. One plus one does not always make two. Where the weight is with a featherbed frame, is extremely important. And 18 inch wheels with a 24.5 degree frame rake, is stupid.
The old theory was, the best motor in the best frame makes the best bike - NOT SO ! - It is simple-minded thinking and it is wrong.
Every racing motorcyclist should ride a genuine Manx at least once in their lives. What you see is sometimes not what you get.
A commando engine in a featherbed frame might be a near-miss to something excellent.
I raced a Triton fairly regularly for 12 years and my mate still has a 650cc Triton at age 83. I have ridden his bike and my own Triton. Mine had the motor an inch further forward and handled better. Back then, I also rode a 500cc Ex Ginger Molloy Manx. The 500cc Manx was streets ahead. What it lost down the straights, it more than made up for in the corners.
When you ride a bike which inspires confidence, you will be faster. When the weight distribution is further back, the bike can feel airy in corners, so you will back off. If you ignore that feeling, you will crash.
 
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I don't think the O.P.'s intent was to go racing, but that never seems to matter...

AMAZINGLY, his original question did get TWO response photos! (and a few related answers)
 
robs ss said:
Some people talk about "balance factor" as if it is some magical way of smoothing the 360 degree twin (or single) when it is actually only trading vertical imbalance for induced horizontal imbalance. (okay - give or take 15 degrees for the "sloping" Commando)
The only "real" way to reduce vibration in these 360 degree twins (or singles) is to reduce the reciprocating mass - the source of the vibration.
Isolastics (which I admire, by the way) are only a way of covering up those vibrations.
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Exactly.
The correct balance factor gives you the same vertical imbalance as the horizontal imbalance. To determine that you have to physically measure how much the engine is shaking vertically compared to how much it is shaking horisontally. You want to err so the vertical vibration is slightly less than the horizontal vibration because your butt doesn't feel the horizontal vibration as much as the vertical. I've made the physical measurments and for a solid frame the factor is in the low 60s for a wet crank (oil included) - calculating dry its in the very low 70s.

Concerning rods the important thing is to use a longer rod because the short stock Norton rod ratio shakes too much. When comparing rods its the small end that creates the vibration - the big end is simply a part of the crank weight. Whether its an aluminum or a steel rod - its important to eliminate the heavy upper rod bushing
 
Wouldn't a 750 Commando engine in a wideline be an Atlas with a very wide tank?
The Atlas engine isn't greatly different from the 750 Commando and the wideline Featherbed isn't greatly different from the Slimline.
The biggest difference might be that the 3" narrowed top section of the Slimline, done for rider comfort as Norton had many complaints about the discomfort caused by the wide tank on the wideline.


Glen
 
worntorn said:
The biggest difference might be that the 3" narrowed top section of the Slimline, done for rider comfort as Norton had many complaints about the discomfort caused by the wide tank on the wideline.
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I read in one mag (Classic Motorcycle) that the reason was to enable the introduction of the rear enclosure tinware added to the Domi-Deluxe. It's the first time I'd heard that though.
 
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