Posted: Mon Nov 01, 2004 6:44 am Post subject: My 850 cafe racer
Nortonfan asked for some details on my cafe racer, so here it is. I built it 10 years ago from a '75 850 Roadster. I probably would not have started with a MkIII, except it was such a "deal". I had this Dunstall double disc front end, a highly modified 850 head, and a Quaife 5-speed, so I figured, build a cafe racer! One thing led to another and I wound up with a pearl white cafe racer with NOS fastback bodywork, a production racer fairing, clip-ons, rearsets, etc. Totally uncomfortable as the seat was too high and the clipons too low (and I'm too old!). So I am now in the process of re-building it with a production racer tank and seat (which is much lower), and clubman bars which are slightly higher. I'm adding a Magura master cylinder to try to help the anemic Dunstall brakes, which means a change to late Ducati switchgear and a matching clutch lever.
Anyway, the engine is a +.020 850 with a cylinder head with reangled oversize intake valves, a porting job, lightened rockers, S&W springs, titanium retainers, hollow adjusters, and lightened lifters. The head is milled up to the edge of the intake valve seat and feeds thru a pair of 34mm Mikuni carbs using individual tapered K&N filters. The cam is a 2S (Combat) grind. Rods are stock but polished and the crank is stock. Ignition is Lucas RITA. Exhaust is stock non-crossover pipes dumping into 1-1/2 inch Bub Conti replica mufflers.
I retained the starter, but put in the 4-pole conversion, welding cable for wiring, and the largest battery I could fit in a non-MkIII battery box. (I am using original fastback side cover and fastback oil tank.) To spin the high compression mill, I had to tighten the anti-kickback washers until they were flat. This makes the sprag clutch even more vulnerable, but it spins and starts the motor pretty easily. I even took off the kickstarter for a while, as it interferes with my right ankle. I'm seriously thinking about one of Dynodave's replacement starters, but my current set up works.
At this point, I looked at the skinny gears of the Quaife, it's higher 1st gear ratio, and decided that rebuilding the stock 4-speed was a better choice. I used a 21 tooth counter shaft sprocket and laced up a 19 inch aluminum front rim and an 18 inch aluminum rear. With a notched chainguard I can mount a 120/90-18 tire. While this looks "modern", the steering is noticeably slower.
I'll be adding one of Norbsa's fork kits and Hagon or Progessive shocks, and probably change the paint scheme to screaming yellow.
The bike runs great, pulling very hard from 3000-7000 rpm. It's the only street Norton I've ever ridden that likes life at the top end. It shut up a bragging Vincent Black Shadow owner in a second gear roll-on, so it runs well enough. The starter and heavy battery goes against the cafe racer image, but what the heck it's my toy!
Joined: 24 Dec 2003 Posts: 362 Location: Brisbane, Australia
Posted: Mon Nov 01, 2004 4:27 pm Post subject:
Ron, thanks for letting us all know what you have built. It sounds nice.
I can relate to getting a bit mature for the clipon position. Having had a back operation for a prolapsed disc 21 years ago, I now have another one, just the next one up at L4/L5. The riding position can be a problem even with my semi-western bars pulled back a bit.
I liked your bit about the Vincent as I ride with a bloke occassionally with one owner also. He loves the fact that it is "The Vincent" & that is the very reason I started the new topic "A living legend, The Norton". In fact he is a metallurgical engineer that had a lot to do with a bike called an RTV, a modernised Vincent. He has one sitting in his shed 3 klms from my home. That is a nice looking machine, barring the new norton iof Kenny Dreers, that RTV is my next choice to own.
What about posting a photo of your "special" for us ?
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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.
