What jet sizes for standard SIL GP200??

[ericthered]

Hi all,

I’m running a standard SIL GP200 with standard Jetex 22mm carb/filter (but airbox drilled), AF Clubman exhaust, factory ‘stage 4 tuned’ barrel (is it really?) and I’ve matched the barrel to inlet manifold, and exhaust manifold and barrel matched to the copper gasket.
I use Rockoil at 4% and super unleaded (97 ron).
It’s a common set up I think so there must be someone out there with lots of miles on the clock who can advise on what jets I should be running? Or at least to within two sizes of the jets??
I’m running very rich at moment because I’m concerned about seizing
What are you running on yours?

Thanks in advance and best regards,
Eric.

[paulnobodyimportant]

Similar setup to yours and mine is

Pilot 45
Choke 50
Main 125
Atomiser 5899-2
Slide 7895-1

Did run it a while with a 123 main jet, but it would nip up on hot days with wide open throttle, so put the 125 jet in and no problems since then.

[ericthered]

Thanks for that Paul. How similar is it?
I've been running a 130 main and 50 pilot, tried a 132 main and it was far too rich.
I've tried a 128 and it did perform better from about half throttle to WOT but after all the engines I wrecked in my younger days (early 80s) I'm paranoid about siezing it up, although the 128 is probably slightly on the rich side too.
Must be loads of riders with my near standard set up and would be good to know what they're jetting is.
Another one if anyone knows, how long should I hold it at WOT before doing the plug chop?
Best regards,
Eric.