Ron L
VIP MEMBER
- Joined
- Feb 27, 2004
- Messages
- 3,231
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!
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!
