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Jeandr
Joined: 22 Jan 2008
Posts: 113
Location: Canada
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 Posted: Wed Jul 16, 2008 8:42 pm Post subject: 80° crankshaft |
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I did the electrics on this bike, it is the most complicated electrical I have ever done and even seen on a British bike. There are 5 fuses, 3 relays (not counting the flasher relay). Boyer microdigital electronic ignition, Sparks 3 phase alternator, LED taillight, halogen headlight, FIVE (5) idiot lights indicating flashers (2), pilot light on, high beam and a spare. CNW electric tach and speedo, oil pressure gauge, oil temperature gauge and voltmeter.
What sets it apart more than anything else, is the 80° crankshaft which is supposed to make it as smooth as a Ducati or a 4 cylinder UJM. The guy did a lot of work himself, especially putting it all together. It's a nice bike, but everything is so tightly packed together it's a nightmare to work on. For example to remove the left hand panel, the seat has to be taken off and then the clip can be maneuvered with fingertips, after that you need to have your hands massaged because of the cramps.
I have a 1Mb (well a bit less) sound file of the engine running if anyone is interested in hearing how it sounds. Send me a PM with your e-mail and I will send it off. It sounds a bit like a Ducati, at least that is what I have been told, the sure thing is it doesn't sound like any Norton you have ever heard.
Jean
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Keith1069
Joined: 10 Jan 2005
Posts: 239
Location: Hampshire UK
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| Posted: Thu Jul 17, 2008 12:00 am Post subject: |
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| Beautiful, very nicely done Jean. i'd love to hear it running. piztonbroke@aol.com |
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Ron L
Joined: 27 Feb 2004
Posts: 1147
Location: Ohio
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| Posted: Thu Jul 17, 2008 3:17 am Post subject: |
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Wow! The more I look at these pictures, the more neat tricks I see! Where did those barrels come from? The work on the left front fork lower is neat! As is the rear brake master cylinder mount. Very unobtrusive.
Sweet machine. |
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panic
Joined: 20 Sep 2005
Posts: 54
Location: Hempstead, New York
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| Posted: Thu Jul 17, 2008 6:00 am Post subject: |
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1. how much did that angle in the carb boot reduce intake efficiency?
2. 80°? Where did that figure come from? |
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grandpaul
Joined: 15 Jan 2008
Posts: 652
Location: Laredo (south) Texas
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| Posted: Thu Jul 17, 2008 6:11 am Post subject: |
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Great mother of Norton. What an amazingly meticulous machine.
I like it "okay".
I would offer more than my customary $350.00 for it, if it was for sale. |
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Hortons Norton
Joined: 12 Oct 2007
Posts: 162
Location: Long Beach, California
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| Posted: Thu Jul 17, 2008 6:23 am Post subject: |
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| Are those Yamaha SR 500 wheels? Looks GREAT!!!!!! WOW, How much were the clocks? Chuck. |
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Jeandr
Joined: 22 Jan 2008
Posts: 113
Location: Canada
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| Posted: Thu Jul 17, 2008 6:50 am Post subject: I only did the electrical system |
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I only did the electrical system on this bike, it's not mine, there is a lot of neat stuff though 
To answer a few questions:
The 80° angle was determined to be the best for a Norton by the guy who does the crankshaft modifications, for a Triumph, the angle is not the same. There is an article about a 90° cranked Norton in Classic Bike Guide (August 2003). The guy who does the 80° crank is from Toronto, check out his web site at http://www.offsetcrank.com/index.html How he came to 80°, you will have to ask him. On his site there is mention of 74°, 80° and 90° of offset, I think he says the 80° is the smoothest.
The carbs are from CNW, including the spigot, IMOHO, not any worse than the stock Norton way to mount their carbs.
I think the barrels came from British Cycle in Nova Scotia http://www.britishcycle.com/ The owner of the bike told me they were an old set British Cycle had and he got them at a discount but he had to do a lot of fitting to get them on because nothing lined up.
The wheels are Morris mags the owner bought in the seventies.
Jean |
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panic
Joined: 20 Sep 2005
Posts: 54
Location: Hempstead, New York
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| Posted: Thu Jul 17, 2008 7:12 am Post subject: |
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In general, the discussion on offset crank angles falls into 2 theoretical categories:
1. 90° produces the best balance of motion between the 2 cylinders - this will always be 90° regardless of engine design, etc.
2. the point where 1 piston is stopped, and the other piston is at maximum velocity (its rod is at 90° to the crank) - this will vary based on rod ratio. The original Triumph design used 76° because that's where the 2.01:1 rod ratio places the throw.
The crank offset angle = 90° minus the maximum thrust angle.
Maximum thrust angle: arc tan (1/(2*rod length)/(stroke length))
The Triumph 650 rod = 6.500”, stroke = 3.228”
(2*rod length) ÷ (stroke length) = 4.027
1 ÷ 4.027 = .2483
arc tan .2483 = 13.94
90 - 13.94 = 76.06°, hence 76°
The Norton rod = 5.875”, stroke = 3.504”
(2*rod length) ÷ (stroke length) = 3.353
1 ÷ 3.717 = .2982
arc tan .2982 = 16.60
90 - 16.60 = 73.40°
80° may have been used (and there are numerous comments that the angle isn't critical to vibration reduction; Yamaha 650 uses 83° because it's almost a bolt-in), but Geoff Collins (who made the crank in that Norton) recommends 90°. |
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Hortons Norton
Joined: 12 Oct 2007
Posts: 162
Location: Long Beach, California
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| Posted: Thu Jul 17, 2008 8:30 am Post subject: |
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Love to hear it, chuckinton@aol.com Thanks, Chuck.  |
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Jeandr
Joined: 22 Jan 2008
Posts: 113
Location: Canada
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| Posted: Thu Jul 17, 2008 1:16 pm Post subject: |
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| panic wrote: | In general, the discussion on offset crank angles falls into 2 theoretical categories:
1. 90° produces the best balance of motion between the 2 cylinders - this will always be 90° regardless of engine design, etc.
2. the point where 1 piston is stopped, and the other piston is at maximum velocity (its rod is at 90° to the crank) - this will vary based on rod ratio. The original Triumph design used 76° because that's where the 2.01:1 rod ratio places the throw.
The crank offset angle = 90° minus the maximum thrust angle.
Maximum thrust angle: arc tan (1/(2*rod length)/(stroke length))
The Triumph 650 rod = 6.500”, stroke = 3.228”
(2*rod length) ÷ (stroke length) = 4.027
1 ÷ 4.027 = .2483
arc tan .2483 = 13.94
90 - 13.94 = 76.06°, hence 76°
The Norton rod = 5.875”, stroke = 3.504”
(2*rod length) ÷ (stroke length) = 3.353
1 ÷ 3.717 = .2982
arc tan .2982 = 16.60
90 - 16.60 = 73.40°
80° may have been used (and there are numerous comments that the angle isn't critical to vibration reduction; Yamaha 650 uses 83° because it's almost a bolt-in), but Geoff Collins (who made the crank in that Norton) recommends 90°. |
Nice math. I always thought the Yamaha was a 180° design, but read this http://www.sense.net/~blaine/270.html they talk about how the cranks are linked together with a 13 spline "coupling", that is where the 83° comes from. The Yamaha is a 360° crank from the factory, mainly for the music it makes I guess 
Jean |
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Jeandr
Joined: 22 Jan 2008
Posts: 113
Location: Canada
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| Posted: Thu Jul 17, 2008 1:27 pm Post subject: |
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 I looked at pictures of Yamaha 650 cranks and they are indeed 180°, who would have believed something written on the internet could be wrong, what is this world coming to?
Jean |
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panic
Joined: 20 Sep 2005
Posts: 54
Location: Hempstead, New York
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| Posted: Thu Jul 17, 2008 2:22 pm Post subject: |
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Re: " Yamaha 650 cranks and they are indeed 180°"
Referring to the SOHC XS-1, XS-650 parallel twins, all of which were 360°. |
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L.A.B.
Moderator
Joined: 20 Nov 2004
Posts: 1946
Location: Norfolk, UK
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| Posted: Thu Jul 17, 2008 2:29 pm Post subject: |
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| I agree with panic, the XS 650 cranks were 360°. (Haynes XS 650 manual mentions it and the manual photos shows it has a 360° crank). |
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mikegray660
Joined: 05 Nov 2006
Posts: 115
Location: Long Island NY (ughhhh)
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| Posted: Thu Jul 17, 2008 2:50 pm Post subject: |
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impressive!  |
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Jeandr
Joined: 22 Jan 2008
Posts: 113
Location: Canada
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| Posted: Thu Jul 17, 2008 6:26 pm Post subject: |
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| L.A.B. wrote: | | I agree with panic, the XS 650 cranks were 360°. (Haynes XS 650 manual mentions it and the manual photos shows it has a 360° crank). |
Mmmmfff pffff (gee it's hard to speak with feet in mouth ) |
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Norton Commando Forum by Corporate Pages Web hosting using phpbb
The Unapproachable Norton Commando
At the end of 1967 the Norton Commando was announced.
The Norton Commando was greeted with a certain amount of scepticism because on first sight the commando appeared to comprise of the old Norton Dominator twin cylinder engine mounted at an inclined angle in a set of new cylinder parts.
It was not realized that the new Norton Commando Isolastic method of engine suspension damped out all engine vibration and produced a machine which had uncanny smoothness for a vertical twin. In due course the critics were silenced and the Norton Commando had the distinction of being regarded as the first of todays so called superbikes. There can be little doubt that the original design concept of the Norton Commando has proved correct, since comparatively few modifications of any real consequence have been made since production commenced during 1968.
Now nearly 40 years later Norton Commando riders like us are a breed of our own, and as far as we are concerned its still more fun to go for a blat on the old Norton Commando, and fast. As a Norton Commando owner and enthusiast, my goal here is to promote and give credit to those who keep the Norton name going.
It is more deserving to give credit to the Commando itself, for after all these years it continues to be respected. The original Commando designers like John Favill are those who deserve the credit for developing this incredible motorcycle.
The Norton Commando Roadster and Interstate of the late seventies, never died. Although the Norton Villiers factory dispersed the tradition lived on. Today Kenny Dreer in the USA is developing the new 952 CC Norton. What a great looking bike this is, and its engineering is still based on the original layout. It will be interesting to see how the new 952CC Norton does in todays tough motorcycle market. One thing is for sure, I would own one if I could afford it.
