Hello all, looking to continue a bit more on my old school tuning of my P200. So far I've got the squish knocked down to a bit under 2 mm, with resulting compression of about 150PSI. I'm running a SIP road pipe and a 24.24 carb - DRT version with increased fuel flow passages.
At high RPM and low load I get a lot of trace knock that doesn't respond to timing (I've tried as low as 18 degrees) and can't be tuned out with idle jet or atomizer (running as rich as it can stomach with the atomizer with no holes in the high RPM portion). I'm pretty much concluding at this point that my port timings won't happily support 6000 RPM scavenging and to fix it that I need to get the port timings better done, probably most easily by raising the barrel and having some chopped off the top of the barrel.
What are reasonable values for either port timings or for the # of mm I can raise the barrel to get along better at high RPM?
Thanks - cheers.
Last edited by sdjohn on Tue Mar 19, 2019 8:21 am; edited 21 times in total