KZ1100 project finalized, now tuning

Hey guys, I'm done with my project, now for the tuning. kz1100 a2 shaft 1982. Pods and aftermarkets installed.
The bike is running lean... hesitation on acceleration with some popping.... some popping in the exhaust on de-acceleration.
The bike runs better when the petcock is at the reserve position... if its at 'on' position, it runs very lean (no acceleration, stalls).
Carbs are clean, installed 2 size larger for main jets, and one size larger for pilot jet.
The air screws are rotated 2.5 turns out.

My questions:
1. the fact that the bike runs better on 'reserve' position, could be the symptom of a bad fuel petcock?
2. I bought a part bike that came with a new aftermarket petcock, but it has no return line nipple... if i replace it with that one, can i just leave the return line open routed under the bike?

first thing I was gonna try tonight after reading stuff on the web, was to enriched by turning the air screws, thats all i got for now.

here are some pictures of my bike

Check the vacuum side of the petcock for leaks.

no leaks on the vacuum side

Move the vacuum line to the petcock from carb #2 to carb #1 and see if that fixes it. (don't forget to move the plug to carb #2). If so, there's something wrong with cylinder #2 (stuck valve etc).

If not, then you probably need to rebuild the petcock. Kits are ~$30.

Thanks for your help guys....

Is it normal that more fuel pass by when the petcock switch is on the 'reserve' side or not???

For me, it should be the same amount of fuel that passes by on 'reserve' and 'fuel' ???

eric951turbo wrote: Thanks for your help guys....

Is it normal that more fuel pass by when the petcock switch is on the 'reserve' side or not???

For me, it should be the same amount of fuel that passes by on 'reserve' and 'fuel' ???

Should be the same amount. The tube inside the tank on the petcock could be pluged with rust or whatever. There's supposed to be a screen in there to keep stuff out, but it may be mising, torn, melted etc. I wouldn't take it apart without the rebuild kit on-hand.

OK... topic update.

I tried the bike again yesterday and played with the switch, reserve to fuel positions, and made no difference... so the petcock is not involved anymore in the problem.

The problems:
1. exhausts/mufflers pops a little from 0 to 3000rpm, with some hesitations for acceleration. when it its around 3.5k... the power is incredible like if it was turbocharge
2. on decelaration, my left muffler will pop a lot, until i press on the clutch

my guess is that I need to play with the air screws and try to adjust. I took the plugs out: #1 was a little white, #2 was totally suited black, 3and4 a little black... so I'm guessing I'm running rich.

My plan for tonight is :
1. check the carbs couplers, seal them with sealant
2. readjust airscrews to 2 turns
3. new plugs

U may have to go up a size on the pilot jet.
Atleast that is what be needed in VM carbs.
I know yours are CV.
U mention your plugs are different color...that would till me that carbs are not working properly.

New update.

I realized that the popping came for cylinder #4. If I unplug the plug on #4, the popping stops.
So far, I've:
1. Cleaned points
2. Swap wires and coil with another coil
3. New spark plugs (getting spark on all of them)
4. Compression good on all cylinders

After all this, no change

Any advice on where could be the problem, out of ideas here

eric951turbo wrote: New update.

I realized that the popping came for cylinder #4. If I unplug the plug on #4, the popping stops.
So far, I've:
1. Cleaned points
2. Swap wires and coil with another coil
3. New spark plugs (getting spark on all of them)
4. Compression good on all cylinders

After all this, no change

Any advice on where could be the problem, out of ideas here

Hey Eric gorgeous bike! I know I'm brand new but read several threads past few days of guys running NGK plugs where it appeared like it was firing but was deceptively wrong. Any chance this may be plaguing you? I'm far from being an expert but your issue "sparked" that potential connection in my head and made me curious. Best of luck on resolving it

- Irish

What jetting are you running and have you check the float levels? Also DO NOT use sealant on any carb fitting, it will not work. If the fuel fittings are leaking between the carbs you can use Teflon tape to seal the fittings.

Tks for comments.
Running NGK spark plugs and caps... But I've tried and swapped different sets, no difference, all good

+2 sizes bigger on main jet, +1 on pilot

I think I may have found the problem. My new air pilot screw... I think I may have bought the wrong ones from z1. The needles at the end of all 4 are a little bended .

I've replaced with the ones on the part bike I bought.

Unable to test now cause I need to fix the fuel tank

Thinking it might be the petcock, (before finding out about the air screws), I removed it and tried replacing with the brand new aftermarket petcock on the part bike.

It was a little dark in my garage and didn't notice that the aftermarket tube was larger.
I bolted it in tight, then I lift the tank and fuel was pouring.

Removed it and notice I blended the surrounding of the peacock hole on the tank.
Crap

Now I'm fixing it with epoxy jbweld
Crossing my fingers on all that crap
Brand new painted reservoir