exhaust port indexing/clocking

Not really important.
But got best performance they could be neither straight on or side on but somewhere in between.

Exhaust front and rear can give a small advantage (<200rpm) as there is better access/flow into the transfer channels.

Even if it did make a difference it would probably be so
Small it wouldn't be of any real benefit. Kris says 200
Rpm well are you really gonna mess around for that?
Go back through my last weeks postings to see how I
Got an extra 4800rpm.
The answer was almost all dependent on cylinder and
Piston selection.
One last thing to bear in mind is at 17.2k my 2oz
Tank lasted 15 mins, at a solid 22k (now I've sorted the
N/V) it lasts 6 mins.
Good luck.
Ps
Welcome to forum

Paul Gibeault mentions that a lot of the mouse racers try to orient the transfer ports on each side(exhaust ports front and rear). He said, personally, that somewhere in between worked best for him. I rebuilt my last Black Widow following his article, except I milled the deck on the crankcase, removing a quarter of a thread to get the transfer ports side to side. The idea being that if both are an equal distance from the incoming fuel/air charge, the maximum amount of fuel will be delivered to the combustion chamber. Or at least the F/A distribution will be even

Never ever use a shim for this purpose. That will reduce the SPI gap and seriously choke the performance (if your GB has SPI). They are for eliminating SPI for those that want to use mufflers(which don't agree with SPI), and possibly throttle rings. A shim would change the timing too, which you would not want.

But, there are so many things that affect how each individual engine runs that we're only guessing and it probably doesn't matter. Besides, a stock Golden Bee cylinder, if I remember correctly, only has one transfer port. If that is the case, then you may do best by positioning it so the transfer port is facing the front or rear. I can think of arguments for either of those. But if you have a late model Cox cylinder, it has dual transfer ports.

RknRusty wrote:Paul Gibeault mentions that a lot of the mouse racers try to orient the transfer ports on each side(exhaust ports front and rear). He said, personally, that somewhere in between worked best for him. I rebuilt my last Black Widow following his article, except I milled the deck on the crankcase, removing a quarter of a thread to get the transfer ports side to side. The idea being that if both are an equal distance from the incoming fuel/air charge, the maximum amount of fuel will be delivered to the combustion chamber. Or at least the F/A distribution will be even

Never ever use a shim for this purpose. That will reduce the SPI gap and seriously choke the performance (if your GB has SPI). They are for eliminating SPI for those that want to use mufflers(which don't agree with SPI), and possibly throttle rings. A shim would change the timing too, which you would not want.

But, there are so many things that affect how each individual engine runs that we're only guessing and it probably doesn't matter. Besides, a stock Golden Bee cylinder, if I remember correctly, only has one transfer port. If that is the case, then you may do best by positioning it so the transfer port is facing the front or rear. I can think of arguments for either of those. But if you have a late model Cox cylinder, it has dual transfer ports.

Good explanation. It is all starting to make a little, albeit very little, sense to me now.

Thank you,

Bob

From what I have learned today, there are good arguments, and good points, for all positions. The ports are fore and aft, and that's where it's gonna run! Have nothing to base testing on, as old cylinder and piston were well worn, and new is .51 piston and cylinder, purchased many years ago and just found, in old box of parts.

Thanks for all the input, David

Funny, 2 weeks ago I lowered the deck height of a Bee
to orient a #2 cylinder and take advantage of the crank
rotation. I went a little too far(+-15 degrees), and used
a cylinder shim to bring it back.
I'm working on a little project to see how much I can get
from a #2 set up. Fun stuff indeed.
Bob