More Frakenbike fun, carb jet questions ?

I had an earlier post on this bike concerning the dual or single throttle cable on the ZN1100 models. I have since aquired a service manual which included the '85 ZN1100 update. The '84s used a single pull cable for the throttle. The single page update for the '85s detailed the adjustment for the dual cable throttle set up. My ZN is an '85 but the carb linkage is only made for the single pull cable, so I assumed it was from an '84 bike. I test rode the bike for a few careful miles, the brakes were iffy, but it ran pretty strong. As part of the rebuilding (learning a lot) process, I disassemble the carb set for cleaning. The mains were 95's all across, the manual specs 122.5 for 1/4 and 127.5 for 2/3. The jet needle was 5FL51, the spec is 5C50. The needle was Y1, spec is Y5. The pilots were 37.5, spec is 37.5. The pilot screw were all out about 4 turns. The bike had been running with Uni pods, was this an attempt at rejecting for them ?

Pods drastically changes the jetting requirements. A Dynojet kit will save you a LOT of trial and error playing with different jets and needles.
www.dynojet.com/pdf/2310.pdf

Should have mentioned I’m replacing the pods with a stock air box and filter. The small main jets with pods seemed odd to me. Probably going to replace the mains and try the needle jets and rods and see how it runs.

Nessism wrote: Pods drastically changes the jetting requirements. A Dynojet kit will save you a LOT of trial and error playing with different jets and needles.
www.dynojet.com/pdf/2310.pdf

Pods should have their own sub-page...

Finally after a year of work, the ZN1100 Frankenbike made it's maiden voyage with almost all the right parts. But now I'm back to the carb jet question. I rode the bike briefly before the tear down and it ran pretty respectably with the pods and stock ('83 kz1100 I think) exhaust. The pilot screws were all out 4 turns when I disassembled the carbs. The main jets were 95's (not drilled out), spec is 122.5 1/4 and 127.5. 2/3. The jet needle was 5FL51, spec is 5C50, the needle was a Y1, spec is Y5. The pilot jets were right with 37.5 installed. Now with the stock air box installed the motor starts and idles just fine, pulls pretty hard up to about 4,000 or so then flattens out. The bike had no tach when I got it so I'm not sure if I pushed it that far or not. The brakes were pretty iffy...... Seems likely it's leaning out now with the stock air box and was probably worse with the pods ? I'm thinking 127.5's straight across since the 1/4 carbs are not connected to the vapor recovery system ?

Vapor recovery system? Do you mean the PAIR system that introduces filtered air into the exhaust system? Is so, it has nothing to do with jetting. If the system is removed, all you need to do is cap the two vacuum ports that operate the system, and cap off the reed cages. Some Califonia-only models did come with a vapor canister that was connected to the fuel tank vent, and likely the carb vents. Removing it should not affect jetting.
As I understand it, some bikes came with different main jets on the outer cylinders in order to run as lean as possible to keep the EPA at bay. The inner two run hotter, so they cannot safely run as lean. Since there are so many non-stock parts in your carbs, I would start with them all set up the same, and then change only one thing at a time. Starting with the 127.5s seems reasonable to me.

I pulled the carbs back out and opened up the mains from to .038 to .051, almost back to the spec size. It pulls hard now up to 7500 where I backed off, have to be considerate of the neighbors.......I realize there's nothing right about drilling jets, but it sort of proved the mains were way too small. A new set of Mikuni 127.5's is on the way. The fuel tank on this bike has the ports for the California emissions plumbing, the hose routing diagram was on the right side cover panel.. It used a liquid/vapor separator with the vapor routed back to the vacuum ports on 1/4 carbs I think. Wasn't sure if they ran the 1/4 leaner to compensate for the vapor or just ran the 2/3 pair richer for cooling.

Interesting. I have never had a bike with that system on it, so I have paid very little attention to it. I would have guessed that the vapors would have been routed to the air box, and that the carb vents, rather than vacuum lines, would have also been connected to the canister.

If those are vents rather than vacuum ports, and you have them capped rather than open to atmosphere, they could contribute to poor running. The bowls must be vented to allow fuel to flow properly.
Edit: I just looked at the diagram at Partzilla, and I see that the system is a bit more complex than I imagined. (Insert feaux shocked face)
I see a vacuum switch operated by a vacuum port on one carb, and I see the tank and carb vents go into the separator, and the vapors go into the air box. Sheesh.

www.partzilla.com/catalog/kawasaki/motor...t-zn1100-b2/canister