TOPIC:

swest wrote: Use the stock Kawasaki jets. Aftermarket parts are not precise. I bought some what I thought were Mikuni main jets and the bike wouldn't run for SHT. I pulled them out and put them side by side with REAL Mikuni jets and the new ones were drilled differently. Just a small thing like that made all the difference. The Yamaha dealer was shocked and gave me a refund.
Steve

I had the EXACT experience!! I was totally blown away by the obvious difference in needle dimensions from $80.00 aftermarket 26mm kit from a reputable dealer. The aftermarket jets were not the same and the needles were at least 25%-30% smaller diameter from tip to clip grooves and the replacement one from an eBay delear was exactly the same... I got refunded twice.
FOUL!!!

Regarding the TK22 carb kits:
The K&L kits had decent jets and needles, and the Keyster kits did as well. So far only the no-name kits with the plain boxes and keyster part numbers had bad needles. I don't recall if we used the pilots and mains from the no-name kit yet, so those parts are yet to be evaluated.

At idle, the bike should be running almost entirely on the pilot system for fuel. The slide cutaway exposes the needle jet to atmospheric pressure, thus there is little to no vacuum to pull fuel up the main. The pilot system lets in air and fuel, but the metered air is for the purpose of controlling the amount of fuel flowing in the pilot system. (Using this method to control the fuel is nice since fuel won't gum up the air screw, since there is no fuel there.) The amount of air actually passing through the pilot system is almost insignificant relative to the air coming through the main slide opening. You can verify this by monitoring the vacuum on a manometer while turning the air screws. It does not alter the vacuum by any measurable amount (relative to the unchanged cylinders). Whereas even the slightest change of the slide adjustment for a given cylinder will alter the vacuum by a large amount (relative to the unchanged cylinders).

So basically, the air screw is a means for adjusting the amount of fuel in the pilot system for idling. But it is not adjusting, by much, the amount of air being burned at idle. The air screw is affecting the amount of vacuum available to the pilot jet for the purpose of pulling up idle fuel. Letting in more air, through the air screw, reduces the amount of vacuum pulling up fuel through the pilot, without altering the total amount of air entering the engine at idle, (by much).

If the pilot system is very lean, to the point that the main circuit is required to provide some of the idle fuel, then the air screws will have much less effect on the mixture. Then closing an air screw might not stall a bike. I usually only see this on bikes with a vacuum leak or fuel level issue, or if the idle mixture is far off for some reason. As a matter of fact, this may have been happening on the bike we were jetting with the faulty needles. After going back to the factory needles, suddenly everything started working properly again.

None of the pilot/idling issues will have too much affect on fuel mileage. That is mostly a factor of the needle and main jet, and maybe slightly a factor of the pilot jet, for slower speeds. Cruising is mostly a needle adjustment area of tuning.

Thanks for all the info loudhvx. I needed to straighten out the overly rich mixture before synchronizing the carbs. They have only been bench synced.

Here is a couple pics of one of the 32 pilot jets in the no name white box. Never installed it and glad I didn't.

One more question for you loudhvx. Should this line and the one for 3 and 4 be plugged? Someone in another post was saying these two original lines should be plugged. I may have not understood there post correctly.

aarb77 wrote: One more question for you loudhvx. Should this line and the one for 3 and 4 be plugged? Someone in another post was saying these two original lines should be plugged. I may have not understood there post correctly.

Absolutely not. Those are the bowl vents. As a matter of fact they are very important, especially with pods. The hoses must come together in a safe location, somewhere underneath the rear of the tank. They need to be out of the most turbulent air, and secured so they don't move about.

I learned this the hard way while doing some wideband testing, recently. One of the vent hoses moved and poked out into the air stream. This caused the mixture to go super lean (by allowing a vacuum to develop inside the bowl). I didn't realize this and assumed a major vac leak had occurred on the intake. Luckily I spotted it before doing any disassembly. I then did another test, moving the hose into, and out of the air stream, and was able to replicate the condition. I actually connect the two together in a T, then cut the remaining pipe of the T off.