Finally had the time for some dyno runs and as some already said here, it’s worth the price and trouble in gold. Found there an easy extra 10% just by swapping main jets. A friendly shop let me had the dyno for the whole of Saturday morning to do as many runs as I wanted at 25$ the hour.
Engine always felt strong but after an initial run of 55 rwhp, jetted up from 130 to 135, then to 140, each change yelded another 2.5 hp, it got worse with 145 mains. Played then with ignition timing but found little power there even if things got a tiny bit better by backing it a good 4 degs from where I was (stock 35 at full advance)
Regretfully, the dynojet setup could not pick up my ignition pulses so RPM and torque could not be calculated. I plotted myself the red torque line from the HP. Looking at the tacho, 140 equals 13,000 rpm, so peak torque is at 8500, peak power at 10,500
61 rwhp is not bad going for a 500c.c. home tune job, still not a match for PeterC’s claimed 63 but then I am running only swap meet ex-GS750 27mm VM’s and not smoothbore CR’s.
Would be nice to hear opinions on this one, my own feeling is that it peaks a bit early, thinking of retarding the cam a bit.
Your ideas will be appreciated.
TG