- Joined
- Nov 21, 2004
- Messages
- 15
Traditionaly speaking any performance modifications start with pipes, mufflers or if the wife allows expensive carbs, this time we will go against the grain straight to the breathing heart of any engine, the CYLINDER HEAD. if your intrested read on. We took an early 70's Norton 750 nothing special, dyno tested it to achive a baseline torque and horsepower at the rear wheel. I a Saturday afternoon we swapped out the stock head and bolted a ported and flow tested head back on, off to the dyno. When the dust was settled we made 8 more horsepower and 10 foot-pounds of torque between 2700 to 5800 rpm. With just cylinder head work the torque gain was 24.7% and horsepower was 18.9% over stock baseline results. When we took it out for a spin the first impressions are of surprising mid-range power and continues pull in the upper rpm band, and in a drag race against an 850, the 750 was three bike lengths ahead and holding. Not bad for just cylinder head work !