I'm puzzled...you said most Jett's won't 4 stroke because they're high performance...now you're saying I can get mine to 4 stroke because they're high performance? In other threads you've called the Rossi a high quality sports engine (no argument there BTW). Which way does the wiggle factor go? Believe me, there's no trick to it even with the zero nitro fuel I was using which you always say is hard to tune.

Your comment about the tuned pipe was something of a diversion too because I'd said I'd lengthened it so it wouldn't come into play. In fact it was 21 1/2" from plug to first baffle so it would have been tuned for around 8000 revs. This was done to make sure it'd have no affect on whatever rev gain the engine made when leaned out from initial 2 stroking.

You're on the right track with the higher than normal BMEP but I'll leave you to think some more on it. I have no idea what you meant about the Diesel forum though.