Cylinder porting

[brian kirby]

Ernie dropped off the Berkshire last night. I looked over the bike and I am really pumped up, the bike has a ton of trick little detail mods that are not "hey, look at me I'm trick" but when you know what you are looking at they are cool. The pipe and the mods done to it dont look like the Cranke mod, they look even better, its really done well. The 100 cylinder has some pretty neat looking port work on it too, and the intake spigot has been bored out. It doesnt look like the exhaust or any of the other port timing has been changed, but the bottom halves of the transfers have been pretty heavily ground on and the exhaust exit has some minor smoothing. There are some spots where the liner and the barrel still have some mismatch and I might clean that up before I put it together. I think it should be a rocket (for a 100).

If anyone is interested I can post some pictures of the porting and see what you Sachs Gurus think about what was done.

Brian

[john durrill]

Brian,
 Please do. It would be nice to see the port work.
Thank You!
 John D.

[socalmx]

Mill the head .060 and you will have a screamer.

[brian kirby]

OK, I worked on the SoCal Berkshire over the weekend and things are looking good. I took the top end off and checked the rod, no play and feels smooth. I took the mag cover off and wiggled the flywheel, very slight play, but still good. I took the Bing 84 (two screw top cap) 28mm carb apart and it looks great inside after some basic cleaning. The numbers on the carb are 1/28/511, anyone know what the 511 means? I am going to ask Bing when I order some parts but I thought I'd ask here in case someone knows. One other thing I noticed, I dont know if the guy that set this bike up back in the day was big or fast or both, but the springs at both ends of the suspension are VERY stiff. Its not stuck forks or shocks either its just really firm springs, far too heavy for my 140lbs.

Now some pictures. First the cylinder porting:







The grinding is only on the bottom half of the transfers, and looks to be well done. There is minor smoothing of the exhaust but not the port window. The intake is 28mm, not sure what it was stock but it looks like it has been ground on too.

Now the pipe mod:







The pipe mod was done very well. The stinger pipe is routed around the shock well. Ernie delivered a PVL with the bike, so all I really need is a piston and a few Bing parts and I should be able to start her up.

Brian

'73 Berkshire