Saw Kemp yesterday,and had a great chat with he and his wife. Saw the original Speed Pony engine, and all the Yosh parts.
He had to have the 590 piston grooves (3) slightly enlarged. Seems you can't get the skinny Yosh rings, but Ducati's fit fine with the grooves widened just slightly.
Compared it to a handy 650 piston. It's much the same, has a dome like the 650 piston, but only about half the height, also cut back skirts. As my engine will be built to current vintage rules, the Yosh pistons would be to big.
Up next was the Yosh 'Ilse of Man' cam. Kemp also had a 550 Webcam handy to compare with. We both agreed that the Yosh cam sure looks like a 'regrind', almost zero cam lobe left on the 'close'. That will make life easier sourcing a cam (no he won't let it go!
). Will plan on doing a regrind to the Yosh specs.
Then we got to the Jerry Branch prepared head.
Wow, I thought the exhaust port was the intake for a moment it was so big!
The exhaust valves are stock Honda, while the intakes are 1mm over size. Its also obvious that the combustion chambers have been cc'd. Mike if your reading this I tried to snatch the head so you 'see it', no luck. Did get challenged to a dyno run though. Given the displacement difference (578 / 590) think a 3rd party flow bench test would be better.
I'm game - Mike / kemp? Did make a last ditch offer to swap him for an 'equal' head - no go.
Of course if I won the flow bench test??
After that we went out to his garage/shop, no cars in here!
Saw his latest cafe 550, kemp you have to post pics or a link. Along with his daily scoot, and his wife's 550 SS. It was partially under covers, as it seems she found out that the lean angle left is not as great as right when you have a side stand. Luckily she has only minor scraps, but some cosmetic work required to the bike. There was also related discussion about the effectiveness of the un-drilled Honda disk he had installed when wet.
A great day, thanks kemp for showing me around.
tintop
