Sent you a PM with some info on a possible local source in the bay area. Nice to see some other folks from Nor Cal on the board.
I forgot all about that part!
I'm at sea level in Silicon Valley, so there's more
air here than, say, Denver -- that means the amount
of gas will have to be increased to match the extra air.
Here's my thinking: this '78 kz1000 was gotten from the original owner who rode it here in Silicon Valley its entire lifespan, and the bike was bought at the local Kaw dealer in 1978, so it probably was set up for sea level.
That means probably has 105 mains and 15 pilots in it based on Mr. O.M. Rock's chart above, but I'll check that today when I retrieve the carb bits out of my Berryman's carb cleaner.
If I find that to be the case, the suggestion of going to 17.5 pilots and 110 mains may do the trick, as the amount of extra air flow is probably minimal on the carb intake side -- what with the stock airbox and filter still in place. The only thing missing on the airbox side is the black plastic snorkel box that connects to the actual airbox contains the air filter element. With that exception, everything's stock: carb-to-airbox rubber boots, airbox, filter element.
And the 'Kawasaki by Kerker' 4-into-1 is a street-baffle (not a racing-baffle) pipe, so the 110 mains (up from 105) may also be fine, as the exhaust is not flowing a ton of extra gas volume over the stock pipes (I'm guessing here).
HOWEVER -- from my 2-stroke street bike experience, we always tried to figure out what larger jet sizes to go to for our engine mods then we went up one jet size larger, then checked the bike out, then reduced the jets until we got good plugs readings. It's really critical on a 2-stroke because every time the piston moves to the top of the bore you get ignition, whereas with my kz1000, it's a little cooler in there, piston only fires every other time.
So.....guess what I'm asking......is it wise to maybe go up to 115 mains, and maybe 20 pilots, then drop back to 110s and 17.5s if the plugs are rich with 115s and 20s?
I haven't ever personally rejetted a 4-stroke motor, only 2-strokes. I always let mechanics do the 4-stroke rejets for me.
