My Norton BVR 5 Valve

Nortonws2021

Joined
Aug 17, 2014
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As a new member, thought I would start with a pic and brief description of my Norton.
Its a Norton BVR. Norton Featherbed WL frame. Engine is a single cylinder 5 valve developed by Brian Valentine (Son of Ron of Weslake fame).
Getting there slowly but have been hung up on the oil tank unions/fittings.....seem to fetch silly money on that auction site and cant seem to source others so guess will have to manufacture them.
Its been sitting around for a few years gathering dust so just want to get it all together.
My Norton BVR 5 ValveBVR Norton 5 Valve by HIGHVIEW SPEED SHOP, on Flickr
 
Triton Thrasher said:
Strange low, wide handlebars.
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Swan neck clipons.
Std on some years of manxes.

It is an interesting bike.
Tell us about that engine - what sort of numbers is it likely to produce.
 
Looks real cool in my eyes. Definitely unique and interesting.
Motor looks smallish in the sideline, but the cool factor surely offsets that.
Seat is also very nice. Is that a period item?
 
Probably easier to list a magazine article from the 1980s for the same engine (albeit in someone else`s bike)......My engine is the `prototype`......It basically explains roughly what the engine is, although its VERY complicated as it all took place once Weslake went pop....
The seat is an original item ive had knocking about for years, this bike originally had a hideous looking long square type seat unit that didn't suit it at all.

My Norton BVR 5 Valveimg026 by HIGHVIEW SPEED SHOP, on Flickr

My Norton BVR 5 Valveimg027 by HIGHVIEW SPEED SHOP, on Flickr

My Norton BVR 5 Valveimg028 by HIGHVIEW SPEED SHOP, on Flickr

My Norton BVR 5 Valveimg029 by HIGHVIEW SPEED SHOP, on Flickr
 
Very tasty. Thought Yamaha had a patent on 5-valve heads?
British Bike Magazine said:
At least part of BVR's demise must be blamed on adverse criticism in one of the classic magazines.
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Possible to elaborate without a law suite?
 
As to the patent issue, I've no idea if it still is, or even ever was.
But Ferrari have used them.
Another Italian (Romanelli?) experimented with up to 7 valves.

A guzzi owning friend was working on his Phd improving flow and combustion efficiency. He was building 5 valve heads, trying differentially sized sized inlet valves to increase swirl for the sort of stratified charge often seen in large compression ignition engines, but with the ability to rev. He was doing this sort of thing back in the early eighties.
Plenty of prior art.
 
........I have that `negative` article in the file, I`ll scan it and put it on here.....although it was a bit dereogatory (spelling?) to be fair all the bad points they pointed out were pretty much true!
The 5 valve issue I have heard before that BVR did receive a strongly worded letter from Yamaha, knowing Brian though I expect it found its way to the bin shortly after being read. I have seen other 5 valve heads so probably was just storm in a tea cup....
 
What does the Yamaha patent for the 5 valve head say, and is it applicable in every country ? If you worry about things like that for a one-off special you are pretty silly. If you are going to do a production run, the issue might be different, however I cannot see how the number of valves in a cylinder head can be patented, unless the design is very unique, and gives a substantial power boost. Try protecting your own intellectual property some time = it is not so easy. Perhaps we should all be paying royalties to the inventor of the Otto cycle ?
 
Great project, however the clipons are dangerous - too wide. If you get into a tank slapper with those, you will be immediately off the bike.
 
acotrel said:
What does the Yamaha patent for the 5 valve head say, and is it applicable in every country ? If you worry about things like that for a one-off special you are pretty silly. If you are going to do a production run, the issue might be different, however I cannot see how the number of valves in a cylinder head can be patented, unless the design is very unique, and gives a substantial power boost. Try protecting your own intellectual property some time = it is not so easy. Perhaps we should all be paying royalties to the inventor of the Otto cycle ?
Click to expand...
At one time the crankshaft as we know it today was patented.
 
acotrel said:
What does the Yamaha patent for the 5 valve head say, and is it applicable in every country ? If you worry about things like that for a one-off special you are pretty silly. If you are going to do a production run, the issue might be different, however I cannot see how the number of valves in a cylinder head can be patented, unless the design is very unique, and gives a substantial power boost. Try protecting your own intellectual property some time = it is not so easy. Perhaps we should all be paying royalties to the inventor of the Otto cycle ?
Click to expand...
At one time the crankshaft as we know it today was patented.
 
acotrel said:
What does the Yamaha patent for the 5 valve head say, and is it applicable in every country ? If you worry about things like that for a one-off special you are pretty silly. If you are going to do a production run, the issue might be different, however I cannot see how the number of valves in a cylinder head can be patented, unless the design is very unique, and gives a substantial power boost. Try protecting your own intellectual property some time = it is not so easy. Perhaps we should all be paying royalties to the inventor of the Otto cycle ?
Click to expand...

To get a worldwide patent on a 5 valve head would be very, very difficult.
If Yamaha, or anyone else, tried to obtain a patent in the UK it would as likely as not be thrown out by the Patent’s office.
There was a story of Yamaha paying a certain motorcycle engineer way back in the 70s for the copyright to the mono shock for their Moto cross, bikes, and then along came a rider into the paddock on a 1950s V Twin Vincent……………………………… :( :eek: :shock:
 
Last time I looked, Vinnies and HRD's had dual rear shocks under the seat. ?
Different setup = different patent.

Simple way around an already existing patent too ....

Monoshocks go a long way back in history though ?
ASL (Air Springs Limited) had pneumatic monoshock front AND rear, circa 1910.
Patent had probably lapsed by the time Yamahahaha looked into it.
Plenty of others had played with the same idea

http://occhiolungo.wordpress.com/2012/0 ... uspension/

My Norton BVR 5 Valve


But we diverge, from 5 valves...

Its a wonder someone hasn't come up with a 6 valve ??
Hard to see where they'd benefit over a good 4 valve setup.
Suzook have made some very torquey 4 valvers, short strokes even.
That twin swirl combustion chamber TSCC design of theirs was good...
 
Four valve Weslake heads on 650 Triumph twins don't seem to do much, however on speedway Jawa engines the 4 valve head is a slight advantage compared with one with a good 2 valve engine. Perhaps if you are not pulling the revs, it doesn't matter much how many valves per cylinder you have ? In a very short stroke 500cc Triumph twin, I can see advantage as the rev. range gets up over 10,000 RPM and it is difficult to get a two valve motor to rev that hard without dropping a valve. I suggest it might not be easy to get a four valve manx engine going faster than a well tuned 2 valve engine. With 5 valves the overhead gear might inhibit how high you can rev it, if it has rockers ? In any case with a manx, the bottom end has to keep up, if you increase it's output.
 
Rohan said:
My Norton BVR 5 Valve


But we diverge, from 5 valves...

Its a wonder someone hasn't come up with a 6 valve ??
Hard to see where they'd benefit over a good 4 valve setup.
Suzook have made some very torquey 4 valvers, short strokes even.
That twin swirl combustion chamber TSCC design of theirs was good...
Click to expand...

Yamaha evaluated 4, 5, 6, and 7 valve designs back in the early '80s when they were trying to decide what the optimum arrangement was, but for testing they only built 4 and 5 valve designs. They settled on the 5-valve design, although they did eventually drop the 5-valve in favor of a 4-valve design. Aprillia also used a 5 valve design single in the Pegaso, but eventually went back to the 4 valve configuration.

Several auto manufacturers have tried 5 valve heads, and eventually gone back to 4 valve designs.

The only modern engine to use a 6 valve head that I could find was Maserati, who built a twin turbo V6 with 6 valve heads back in '85 or so, but cancelled it before it got to production.

Just to show that not much is new, Delahaye built an experimental 85 liter four cylinder boat racing engine that had 6 valves/cylinder back in 1905.

Ken

Ken
 
Rohan said:
Last time I looked, Vinnies and HRD's had dual rear shocks under the seat. ?
Different setup = different patent.

...
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All series D Vincents (the last series built) use coil over monoshock rear suspension and have a fully suspended seat. It is a better system than the earlier Vincent three-in-a-row dual springbox/separate dampener in centre rear suspension.

Glen
 
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