FCR33 Carb dyno run

Here's a dyno chart image of Don's 850 with FRC33 small body carbs putting out 60 HP running a bit rich with stock mufflers (Long rods, lightweight pistons, JS1 cam, beespring & valve kit).



A short vid with reverse cone megaphones replacing the stock mufflers - it went from rich to lean with the same jets.

Hi Jim, that torque curve is amazing. Was there any other work done on the head, eg porting, larger valves? Thanks, Graham.

Who did the Dyno run for you or Don?

I should get my other than Commando Norton on a Dyno. Pretty sure I can make better HP numbers than the stock 750 ever made, which according to my Haynes manual was 60 HP standard and 65 HP in the Combat configuration.

According to my Haynes manual 60hp was stock for an 850. Although it doesn't say how or where the HP was measured.

I know members here pooh pooh Haynes. I am not caring.

The solid line of the dyno graph at top is HP and the dotted line is torque.

Check out the thread at the link below and you'll see that actual dyno tests showed stock 850 HP to be mid 40s at the rear wheel (not the crank which is higher).
https://www.accessnorton.com/NortonCommando/commando-hp-and-torque.36286/

I'll ask Don if there was port work or big valves. He does have high compression pistons and gapless rings. His dyno charts show rear wheel HP as shown in the vid.