Dreer VR880

Rohan said:

The other side to this weight business is that I've seen it said that a Norton Commando, for example, could have been made more reliable if it was heavier.

Actually, the bits could have been made stronger, and a bit more weight is the result.

This actually happened over the years with the Commando, and preceding models.
Alloy fork sliders were made stronger/oval.
Gasket faces in various places were made slightly wider = bit more weight.
Gearbox shell was made stronger - bit more weight.
Tanks /sidecovers were made stronger, steel = bit more weight.
(Always thought stronger sidecovers was a very useful improvement ??).
And so on...

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This is true and accounts for some of the extra weight of the later bikes (aside from the estarter) The mk3 s have stronger crankcases and crankshaft according to Haynes. What the Haynes manual doesnt say is how the crankshaft in the mk 3 was made stronger than previous bikes.

On edit:
More reading provided the answer- the crank assembly bolts were increased in size to 3/8 " for the MK3. There may also be a difference in the alignment system, it uses either one shouldered bolt and two "fitting" bolts (early mk 3) or 3 fitting bolts (later)
I wonder if many of the Dreer 880s used the mk 3 crank as a starting point for his mods, and if this might give them a better chance of hanging together?

Jaw, Commando or no Commando you are welcome in our club. I sense that you will have a Commando in the garage before the year is out. Too bad they are so expensive in your part of the world. Have you looked into the cost of shipping from other areas?
I have heard it said that the west coast of Canada is the lowest priced market for British bikes, not sure if its true but there are some real bargains here.


Glen

worntorn said:

On edit:
More reading provided the answer- the crank assembly bolts were increased in size to 3/8 " for the MK3. There may also be a difference in the alignment system, it uses either one shouldered bolt and two "fitting" bolts (early mk 3) or 3 fitting bolts (later)
I wonder if many of the Dreer 880s used the mk 3 crank as a starting point for his mods, and if this might give them a better chance of hanging together?

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I was extremely surprised to hear the Dreer bikes didn't replace that Commando cast iron centre flywheel with a steel item, given they upped the performance 50% apparently - the cast iron bit had been a known high performance weak point for decades - 1930s race Nortons (cammys) had proper steel flywheels even. Didn't one of the JPN bikes at Daytona puncture his back wheel with the exploding iron crank centre.... ?!!

Cheers Glen, I am keen to go Commando, & this forum has been both informative & fun.[Although L.A.B., - could we have a sticky with reputable vendor/empirically-based best mechanical 'recipe' lists?]I will do due dilligence in sourcing either a core bike to do up &/or a shopping list of best-practice items to do a reasonably rational attempt at a sturdy Norton that can be enjoyed as the maker might have granted to a good-un.
From my reading, the factory crank approach was very ad-hoc.

The crank design may have been 'ad-hoc'.
But unless you rev the zinger out of it, it is perfectly strong enough for average road riding.
As many surviving Commandos can attest to.

And if you do rev the zinger out of it, you are either a racer and already have an all steel crank - or should be on a Kawasaki etc...

BTW, it is recorded that Bert Hopwood designed the original Dommie Model 7 twin with a differrent (one-piece ?) crankshaft design. But the machine shop said they couldn't manufacture it. (So who designed what they went with ??)

Duh, its all a crap shoot form the material cast to the processing done later even if rather universal 360' design. The most dramatic tale told of the brittle nature of Cdo flywheel was a fellas 850 idling in driveway when chunk left out the front cases crossing the street in flight to bounce off a car hood through picture window and living room items and though some sheet rock. As crank cheek/journals jerk pistons down the flywheel deflection is forward and downward about 7:30 level as witness marks inside Peel revealed w/o any broken parts [inside] to confuse the issue. If i was to shoot for a hi rpm Norton with a normal crank shape I'd offset the flywheel to compensate toward center line a few mils and also the items on its ends. Can ya even imagine the bad taste Kenny Dreer gets thinking about Norton Commandos any more.

hobot said:

. If i was to shoot for a hi rpm Norton with a normal crank shape I'd offset the flywheel to compensate toward center line a few mils and also the items on its ends..

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What does this actually mean, Steve ?

BSA flywheels were oval shape at one time, get more mass where its needed for counterbalance duty, and keep the weight down. Apart from being difficult to manufacture, not sure where they went with that, but used it for a while...

Aw Rohan now ya exceeded my data base that only covers the principle of pre-stressed-bowed beams not spinning cranks. I've seen the anaphylactic shock of Norton rpm allergy so particularly fascinated to learn various types of vaccinations to stave off sudden rashes of destruction. I've a spirograph planetary gear crankshaft design that might eliminate any crank rpm limits but complex to produce but no rod bolts or caps or piston pins to flail. If they only pumped nitromethane to public we could have TC reliable engines to scare the living daylights out of un-tamed isolastics. I'm aiming for torque not rpm in Peel. I've seen the light and will fix up witness probes on flywheel and crank ends so when they show some threshold of deflection I'll know better where to set rev limiter. Any ID on what deflections are common to just tolerable?>

hobot said:

I've seen the light and will fix up witness probes on flywheel and crank ends so when they show some threshold of deflection I'll know better where to set rev limiter. Any ID on what deflections are common to just tolerable?>

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This sounds like where you torque up a bolt until it breaks, and set the torque wrench a bit below that. Not sure I'd want to experiment with cranks to find that limit though ?!!
Your Suzook is supposed to be pretty tough, keep it for the redline work and keep the Nortons on the road in one piece ?

Not even sure where any crank deflection could be measured, let alone what is critical.
Testing things to destruction is something that even race teams prefer not to do ?
You road riding this, or intending to break the sound barrier ?
Little indicator tabs inside the crankcase closely set to the crank may show something, but you'd have to be certain that oil swirl wouldn't interfere.

hobot said:

Duh, its all a crap shoot form the material cast to the processing done later even if rather universal 360' design. The most dramatic tale told of the brittle nature of Cdo flywheel was a fellas 850 idling in driveway when chunk left out the front cases crossing the street in flight to bounce off a car hood through picture window and living room items and though some sheet rock. As crank cheek/journals jerk pistons down the flywheel deflection is forward and downward about 7:30 level as witness marks inside Peel revealed w/o any broken parts [inside] to confuse the issue. If i was to shoot for a hi rpm Norton with a normal crank shape I'd offset the flywheel to compensate toward center line a few mils and also the items on its ends. Can ya even imagine the bad taste Kenny Dreer gets thinking about Norton Commandos any more.

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Last I heard Kenny was still restoring the occasional Cdo. Back to his roots I guess.

Snorton74 said:

hobot said:

Duh, its all a crap shoot form the material cast to the processing done later even if rather universal 360' design. The most dramatic tale told of the brittle nature of Cdo flywheel was a fellas 850 idling in driveway when chunk left out the front cases crossing the street in flight to bounce off a car hood through picture window and living room items and though some sheet rock. As crank cheek/journals jerk pistons down the flywheel deflection is forward and downward about 7:30 level as witness marks inside Peel revealed w/o any broken parts [inside] to confuse the issue. If i was to shoot for a hi rpm Norton with a normal crank shape I'd offset the flywheel to compensate toward center line a few mils and also the items on its ends. Can ya even imagine the bad taste Kenny Dreer gets thinking about Norton Commandos any more.

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Last I heard Kenny was still restoring the occasional Cdo. Back to his roots I guess.

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He's been too busy drag racing.

He was talking about building one more Norton from some spares he has but I don't know how far he got.

For about 3 yrs, I communed with Kenny and Linda while scratching both my ends on what to do and buy for my 1st ever Combat with 14 leaks and whole bunch of major stuff bad after being a shop's test bike that beat everything around for a decade and still famous in a few counties around, it became a Her/She with a name and I became totally insane speed demon I'll never get over. This covered the period of time Kenny was coming to grips with taking a huge risk quitting the old stuff and starting out fighting the world and himself giving birth to a New Norton. Dreer is part of Ms Peel's head and heart space, who's new mission is indeed approach breaking the sound barrier in handling and acceleration beyond anything out there but pure drag bikes that can't handle much power leaning any. Its entirely possible next Peel will break under 10 sec 1/4 mile going by power/weight calc's if I can hook it up. None of the off the shelf elites like SR1000 can break under 10 sec 1/4 mile going by the magazine reports. Can ya imagine how those hot shots would feel being blown off by a 40 yr old clunker design : )

Crank witness would be a composite bolt run up in bottom of case to touch flywheel, then measure how much is worn off by how much it can be run in after stages of rpm tests. I could also open up and check rod shells for uneven wear as deflection would mess with their square matting and oil wedge separation. The Drouin pulley would be another place to glue foam block next too and watch for its wearing off alert. Builders tell me crank end run out of .002" is race worthy. I'd also need the spec's on how much deflection the superblends can tolerate. Peel's crank is welded and nitrided and 4 lb lighter and 1/2" smaller OD and slinging the light JMS pistons/rods. Peels whole power unit is cryogenic tempered so tougher than average and might get away with more than expected. A little known fact is the pressure above pistons acts like lighter pistons at TDC which increases effective BF% and helps tame crank flex at this peak of deflection point jerking down from a stop on intake stroke and relieves some crank stress compressing more PSI @ TDC. Engine Calc's with Drouin exponential boost curve go freaking out of sight after 7000 rpm. I do want to be able to reach 8000 for a time now and then.

One thing I think I've run into is exceeding tire H 130 speed rating on past Peel in her prime was the tires suddenly expand so top off speed increased while rpm stayed the same. So that's another place for foam block witness to hold off till better equipped. There was about 4-5 places on 15 miles of hwy I wound shove speedo to 130 in seconds on daily commutes, after I saw way was clear and not running right up on tails of hyw patrol. Next Peel will be able to easy exceed that in a dozen places between the bends as won't hardly need to slow down for turns I've found. No matter how fast Peel is capable of in bee lines it pales to how much speed she can take severe turns on. You just have no idea nor Kenny of how it feels to have a WOT wheelie dragster pull like water skier on wrists and brain blood draining through chicanes and sweepers. I've never read of Drouin feeding a big block hi CR drag race engine and maybe I can handle it to make some Norton news to gloat on.
Then there's still methanol and nitromethane and NOS injection if i get bored and Peel still intact.

I dream of going neck and neck on a track with GP bikers at limits in sweepers, to give a nod to em long enough to glimce tank logo, just before Peels' front drops 3" down as I nail it to float front level and flat unicycle lean past the the corner crippled things to squirm on their over rigid chassis and sloppy balloon tire misery. I'll definitely make a trip to let Dreer have his way with her to compare notes with rest of the world. Only lack most of $10,000 more to go on top of about 3'x that so far. So what keeps you'all restless trying to get to sleep?

hobot said:

Can ya imagine how those hot shots would feel being blown off by a 40 yr old clunker design : )

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Ya dreaming, Steve. Unless you catch them napping.
See below.

hobot said:

I do want to be able to reach 8000 for a time now and then.

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Stick to your Suzuki for the over the red-line stuff , keep the Commando for the good times ?
Was eyeballing a little Kwaka recently, 18.000 rpm redline was it.
All revs and no go maybe, but it had some go.

Rohan stick to what you know but I'm long gone on another level of Norton and Commando performance envelopes than most can relate too including my rational side. After I warm up on a bike I soon find out how much more power I could handle I rate regular combat below a good harley handling and power wise and my SV650 dam site faster safer than a good ole Combat. My SV650 with suspension mods and great tire could whip the hot shot 600's here until road opened and speeds over 90 then no way to kept up game over in seconds. Ms Peel in her prime could wipe up my SV650 in the harshest turning and out run it easy after 60's mph, so best 600's in 05' didnt stand a chance till over 135 they could walk past Peel in opens longer than 10th mile. Peel pulled better up to 130 before pull eased.

Only 900's and above could out run Peel in opens after 90 mph but boy howdy they had to work for it once past the leaning parts. Reading racer speeds Peel seemed very close to their top out reports. I kind go by my inner expressions on first exploring various engine pulls, Oh yeah, Oh Boy, Oh Wow and OH SHIT! Peel was mostly Oh Wow, my P!! was always OH SHIT! I was so surprised after run in when I decided to see what I had and literally ended up on tail lens the first time I nailed Peel on Gravel driveway in 2nd. Peel was OH SHIT fast in upper zones of 1st to 60 and 2nd to 90 into red zone then only Oh Boy in 3rd and 4th. I had times on Peel I'll never ever forget and in lots of ways could die happy on her adventures and high times. If I live long enough to field next version its just magical extra icing to consume before my end. Kenny Dreer would understand.

hobot said:

Rohan stick to what you know but I'm long gone on another level of Norton and Commando performance envelopes than most can relate too including my rational side.

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Steve, no offence, but how many words do you pen for every minute your Nortons spend above 90 mph ?

Interesting Read..............

Actually, Me and another fellow had a nice visit with Mr Dreer today, 3.5 hours of the mans valuable time. As usual, I am very appreciative when Kenny shares his secrets with me, and todays discussion was very informative. We discussed at length the VR series of bikes, and of course the state of affairs with that fellow over in Blighty having a rough go of things as of late.
Kenny went over in detail many of the parts in the VR series of bikes, and expressed regret that he didnt use 1 piece solid billet cranks in those bikes, as he termed them with the cast cranks,, "Grenades", and "time bombs" We got to hold, fondle and examine the castings for the VR series of bikes,, including an early prototype head made with cornflakes, it was never made into a casting,, it was just a development piece that never made it into metal.

Despite being told im full of it on here,,, I was rather amused when reviewing a VINTAGE custom Commando he is nearly done with for a well known TV star, but the bike, while stunning in every respect, was largely stock internally. Kenny was very insistent that he has had a total change of heart about vintage Nortons, (this is the amusing part to me) he exclaimed,, "its a waste of time to hotrod vintage Nortons" and how if pushed past their limits of design, they are just grenades. The bike on the bench is almost all stock internally,
Kenny used to do extensive mods on the primarys with vents, holes and cool belt drives
(I love a nice belt drive set up with big holes machined in the covers) and Kenny used to be a master at these. But this bike in question, had no holes (Swiss or otherwise) and was running a,,,, gasp,, ack,,, cough, cough,, a stock chain primary., (Ye gads!, ahem).
I told him about my previous posts on here on the blueprinting and Nortons defects, and being ridiculed, he had a good laugh at that.
He also said several times today that he doesnt often go on the net to look at stuff about Nortons, but he said most people dont know what they are talking about.
Ill try and post s afew peektures soon..
But in REALLY REALLY good news, he agreed to do another seminar and technical discussion at our local NW Vintage car and motorcycle museum, stay tuned kiddies, pencil in some time this winter for a trip here to Oregon, and Ill be posting dates in the next few weeks for the upcoming class's and seminars at the museum. Feel free to show up and tell me im full of it, kick me in the shins, knock my bike off its side stand, and get your pix taken with Kenny, as long as you donate to our museum, im a happy camper.

Its been known since the 1950s that the cast iron centre bit was the weak bit in Nortons cranks.
Or was that 1940s, when they were designed - and Nortons machine shop said they couldn't manufacture it as a steel one piece, as designed.

Or was that the 1930s, since cammy/race Nortons have all steel flywheels (they are a single cylinder though), no iron anywhere...

We look forward to these pics. And some explanation of things said...

If I understand this discussion correctly, everyone agrees that Norton designed some good engines. Quality control was something that escaped the British manufacturing industry during the 1970s.

The C'do engine was already stressed about as far as it could be stressed. It was the first superbike and some people, like Hobot and Kenny Dreer, view them as that. Rohan looks at is as an old bike best babied. It seems to me that Rohan looks at the survivors as proof that they were good straight out of the factory.

Kenny spent a lot of years and a lot of money (his and other folks) to come back to blue-printed stock is the best for reliability. He stopped building VR bikes and moved up to the 961 because he wanted more power.

If I get this right, some people are saying great bikes once put together correctly. Rohan doesn't it view it that way because they were fine from the factory.

What am I missing?

Is there a question there anywhere ??
Or any new revelations here anywhere.

As a 17 year old, I had a look at the iron centre section of my 1951 Model 7 dommie twin (all iron engine, BTW). It wasn't exactly new when I got it. This was a known problem even back then, although the 500s were reasonably reliable in the crank and rod dept, compared to Triumphs anyway, unless you tuned them (like making it a 600, like the Factory did !!).

And folks who know their Manx Nortons used to say that Manxes out of the factory were raw material to strip down and 'carefully' assemble, or it was no good. Sound familiar here ??
Tell us something we don't know ?!?!

P.S. So far all we have had that the cranks were 'defective' in some way is some vague words, nothing definite actually quoted, or any demonstration whatsoever as to what is supposed to be so wrong about them ???

BTW, the cast iron centre section flywheel in Norton twin engines appears to be absolutely symmetrical - so it can be (accidentally) reversed if not marked beforehand.

Is this so for all Norton twin engines, including the Commando. ??

Folks who have done this (reversed it) have reported it still runs fine, and doesn't appear to even affect engine balance. What does this say about how the engine is balanced ?