Commando in Context.

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Thanks Bill, spark ignition/compression ignition is irrelevant to whether the cylinder is firing on every down-stroke or mucking around[working at a loss] in between firing strokes, nor whether externally scavenged or supercharged or running on propane or burger grease...essentially 4 strokes = 1 power stroke & 3 to wear the engine out [Sir Stanley Hooker R.R./Bristol aero-engineer].
The fact is, with DFI 2Ts keep their mass/specific output/eagerness advantages & are clean/efficient too.
I like the Commando because despite its inherent 'issues' it is still stacks up as a light/compact/punchy/sporty/attractive/rewarding ride, so does the H2.
 
Indeed Matt, both Commando & L.C. were designed/styled by Bob Trigg. In fact if you have a good look you can see that NVT didn`t just take over the rotary from BSA, the L.C. Yamaha chassis owes a great deal to the D. Hele BSA MC1 250 G.P. prototype, what with NVT earning their living from Yamaha, doing consulting work in the late `70s.
 
From 'The Motorcycle World' by Phil Schilling 1974,
P. 142; Has a a lovely Douglas Wharton Mellor full colour shot of a 750 roadster in deep gleaming black,equipped with disc, black barrels,peashooters - all lean, muscular, sweeping angles -bright parts glinting in the warm golden sunset tones..beautiful..
On P. 161; "Did the enthusiast love the British bits & pieces approach to fast motorcycling?
The Norton Commando demonstrated that England was the home of the creative conservative..."
 
if you claim a 4 stroke is working at a loss than why is it more fuel efficient and why is the fuel consumption much higher on the ring ding in real riding?? my Norton gives me 53 MPG while most H2's I have ridden with only gives at best 35 MPG??? as to engine wear every 2 smoke i have rebuilt (mostly outboards) they all have massive cylinder wear in the port aria V a 4 stroke with more time on it. as to a clean running engine you have to keep the lube oil out of the combustion process hence the orbital-detroit type of 2 smoke engine or it will always be dirtier than a 4 stroke.

J.A.W. said:
Thanks Bill, spark ignition/compression ignition is irrelevant to whether the cylinder is firing on every down-stroke or mucking around[working at a loss] in between firing strokes, nor whether externally scavenged or supercharged or running on propane or burger grease...essentially 4 strokes = 1 power stroke & 3 to wear the engine out [Sir Stanley Hooker R.R./Bristol aero-engineer].
The fact is, with DFI 2Ts keep their mass/specific output/eagerness advantages & are clean/efficient too.
I like the Commando because despite its inherent 'issues' it is still stacks up as a light/compact/punchy/sporty/attractive/rewarding ride, so does the H2.
Click to expand...
 
Bill, you have to get in to the 20th century, I ride a Yam RZ 350 to work, it has reed valve inlet/ rotary valve exhaust & does 55mpg too, the new DFI 2Ts [see BRP E-tec] are California emissions standard compliant, & only inject the fuel after the exhaust port has closed..run on 100:1 oil injection , no visible smoke..
 
Cycle World Sept `12 P.53;
"Rotax, which makes the 800cc & 900cc twins for BMW & Husqvarna, has also been developing low-emissions 2Ts for its parent company`s Ski-Doo snowmobiles, & its 600cc E-Tec [120hp] DFI 2T is in production. A single cyl slice from that 2T would make a very interesting 300cc engine for an off-road or dual-sport motorcycle. If the strong hints dropped by Husky executives prove true, it may not be too long before something like that enters production -- whoever makes the engine.
A lightweight & powerful street-legal 2T enduro? We can only hope, & perhaps such a machine may even have polished-aluminium knee-grips on its fuel tank. Even if it doesn`t, we`re sure Steve Mc Queen would approve."
 
Up until a couple of years ago, I was in Bill's camp on 4stroke vs 2. Summer before last I restored two 1972 Ossa 250cc Mick Andrews Replicas. One was in many pieces, all of which had been stored in a damp barn for 15 years. The other had been run for many hours on trails and gravel roads without benefit of an air filter. Understandably, it had almost no compression, so it required a rebore plus new piston and rings. ill say that it was nice to do a top end rebuild without the usual 4 stroke requirement of rebuilding the valve train!

What impressed me most about these motors was their rugged simplicity and also the good power output for the weight and size.
I was astonished at the condition of the bottom ends, both awash in perfectly clean oil without a visible spec of contaminant.
How does that happen with only that little bit of thin black 2 stroke oil going into the fuel? I know the theory, but the cleanliness of both bottom ends seems at odds with the general image of a dirty, shortlived 2 stroke engine.
Ive taken a number of 4 strokes apart, they all had some sludge somewhere.
I dont think Ive ever worn out the bottom end on any two stroke engine, even after decades of use and abuse. They are a very tough type of engine, too bad about the EPA thing.

Glen
 
The DFI solves 'the EPA thing' & the wasted fuel thing in one fell swoop, the only stickler to a new generation of 2T bikes is the stick-in-the-muds/purblind, hide-bound traditionalists, & the company bean counters who listen to them.
 
wow I am impressed, an engine with half the displacement only equaling my 40 year old Norton. so much for fuel efficiency :roll: and if you did not know it is now the 21st century and where are the ring ding street bikes and automobiles??? it is a well known fact that if any engine uses oil it will not meet the emissions and will kill the catylitac converter used on road going vehicles. just because you don't see any smoke does not mean it is clean burning as you have NOX as a major player!!

J.A.W. said:
Bill, you have to get in to the 20th century, I ride a Yam RZ 350 to work, it has reed valve inlet/ rotary valve exhaust & does 55mpg too, the new DFI 2Ts [see BRP E-tec] are California emissions standard compliant, & only inject the fuel after the exhaust port has closed..run on 100:1 oil injection , no visible smoke..
Click to expand...
 
More from 'The Motorcycle World' on Commandos..
..."the Commando frame isolated the shaker twin by mounting it in rubber. The engine was canted forward by 15 degrees, bolted to the separate transmission with a pair of steel plates which also carried the pivot for the swinging arm. This whole sub-assembly was rubber mounted to the mainframe by means of Silentbloc shock mounts. By all that was known, this should have wrecked the motorcycle`s handling. After all, one could move the rear wheel laterally, realative to the mainframe by hand, such slop between swing-arm pivot & the steering neck should have planted the rider in the bushes at the 1st curve.
Only it didn`t work out that way.
Confounding all the nay-sayers, who thought the frame would bury the Norton name with the 1st few Commando riders, the bike proved a good steerer."
I wonder if that lateral flex or [lack of it, with the carbon-stiff chassis] is what confounded Ducati with their G.P. bike?
 
Bill, do you actually read the posts before responding? have seen an Evinrude E-Tec outboard? [Euro & CARB compliant] do you realize that 2Ts are in fact much cleaner NOX-wise than 4Ts due to inherent combustion characteristics? & Yes, the 20th century thing relates to the date my 55mpg Yam was built, 1985..
 
don't get me wrong as the 2 smoke had its place years ago but as technology has increased it is a dying engine design. yes it is a simple engine to work on but a very complex engine to to modifie as port timing and exhaust is a black art and also to clean up the exhaust emissions. if it was such a great engine where are the new motorcycle's with a ring ding engine???? as to the clean bottom end it stays awash in clean fuel and oil not the same hopefully filtered oil as it is all used in the combustion process. the dirty part is only out the exhaust pipe and it is a major concern, do you remember so cal air in the late 60's and 70's and even some aisan country's today??? I am not an EPA nazi but facts are facts and the engines needed cleaning up, both 4 and 2 strokes.

worntorn said:
Up until a couple of years ago, I was in Bill's camp on 4stroke vs 2. Summer before last I restored two 1972 Ossa 250cc Mick Andrews Replicas. One was in many pieces, all of which had been stored in a damp barn for 15 years. The other had been run for many hours on trails and gravel roads without benefit of an air filter. Understandably, it had almost no compression, so it required a rebore plus new piston and rings. ill say that it was nice to do a top end rebuild without the usual 4 stroke requirement of rebuilding the valve train!

What impressed me most about these motors was their rugged simplicity and also the good power output for the weight and size.
I was astonished at the condition of the bottom ends, both awash in perfectly clean oil without a visible spec of contaminant.
How does that happen with only that little bit of thin black 2 stroke oil going into the fuel? I know the theory, but the cleanliness of both bottom ends seems at odds with the general image of a dirty, shortlived 2 stroke engine.
Ive taken a number of 4 strokes apart, they all had some sludge somewhere.
I dont think Ive ever worn out the bottom end on any two stroke engine, even after decades of use and abuse. They are a very tough type of engine, too bad about the EPA thing.

Glen
Click to expand...
 
Bill, you need to get with the 21st century...look at the link on my previous post...
 
bill said:
I just so happen to own 2 chain saw's a small poulin for light brush and a stihl. both of them are good for what they are. a 2 smoke is also a good engine for weed eater's and leaf blowers and IMHO that is where they should stay, well maybe a moped :lol: but the exhaust emissions have pretty much done away with them in most first world country's. you still did not respond to my example of how engine layout has a dramatic effect on vibration????

J.A.W. said:
Bill, have you ever used a chainsaw? ever thought why Honda does not sell them?
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Don't count them out yet... The old 70's street bikes began with piston port engines that were soggy as shit on the bottom end. Reed valves changed that. High steppin' rotary valve engines made arm straightening power after that. Exhaust power valves took it a BIG step further, first on dirt bikes, my '89 Rotax powered Ski-Doo was the first to have on the snow. This modern Rotax engine meets EPA regs and shits out 164 h.p from 800cc. When you read the fuel economy, remember the rolling resistance of a sled is triple that of a bike. I've dreamed of putting one on a sport bike, with a CVT drive. It's how I get my fix during the cold months... (but without the rubber engine mounting, you couldn't hang on to the bastid!) http://www.ski-doo.com/technologies/eng ... rokes.aspx
 
A light, compact 800cc twin putting out 160+hp, needs an iso chassis,[quick! call Hobot] - maybe problems hanging on may be related to more than the vibes? Maybe they need to make it a 1200 triple so as to smooth her out some, L.O.L.
 
shouldn`t a URAL be your cup of ?

Commando in Context.


"The latest machine from Ural looks as far back into the past as the Russian sidecar industry can go, harking all the way to 1942 when the first M72 motorcycles were sent into the Battle of Stalingrad."

And the period active traffic control methods,

" And yes, there's also that machine gun mount."

Saw one of these stropping down the racer road the other weekend . From the grins , they 'd manadged the greatest enjoymet factor .
Two guys were nailed 45 kph over the 60 km speed limit .Instant loss of liscence and impounding of numberplate & a grand or twos fine.

One they let him use till 8pm to get home , the other on P plates , instant .Heard a rattle out there the day before through the window,
throttle on downhill. Was a DB 9 Aston zinging past . They appear to have some accelerating .Reviseing my opinion of the devices .
Appeared as a big wide flat thing in the rear view mirror , with tyres a foot wide or more.Possibly not much use on gravle roads . :?
 
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