kz1000/vm26 tuning struggles-help pretty please!

Hello all. It has been way too long since I posted on here, mostly because I am stubborn and don't like to ask for help.

Some backround: 76 kz900 with 77 1000 engine installed this last winter. (had a tranny problem with the 900 and found the 1000 motor complete pretty cheap) I went through and regasketed and cleaned 1000 motor before install. I am running the vm26 carbs off of the 900(id# z12 00), k&n pods, and a v&h megaphone with street(quietest) baffle installed. Compression is around 135 on all 4 cylinders. dyna s ignition, coils, functioning advancer, b8es plugs gapped to .032, cam timing correct, valve clearances correct, wg coil mod with full voltage to coils, carbs synced, and I am 800ft above sea level. When these parts were on the 900 motor, I was running 17.5 pilots, 117.5 mains, clip in 3rd position, air screws around 1 1/4 turns out, and it ran flawlessly.

When I got the bike running this spring with the bigger motor, that is when the problems started. Bike ran pretty good except at wide open throttle, would accelerate slowly, if I backed off throttle a little it ran better, which some research told me meant I needed bigger mains. Electrodes on plugs were white, which also said lean to me. I ordered some 120's, and while I had the carbs off I decided to set my fuel level with the clear tube method instead of the static float height I had done before. I built a holder and got the carbs perfectly level. All four floats where set too high, fuel level even with mating flange, so I lowered them an 1/8" till they were an 1/8" below mating surface per service manual. I installed the 120 mains and headed out to bask in the glory of my mechanical wizardry. Not so much. Bike runs like crap everywhere till it warms up, stutters, won't accelerate cleanly, doesn't like too much throttle, etc. Once it is up to temp, it runs better, but still crappy. Idles ok, part throttle surges, 1/2 throttle surges and pops through carbs, full throttle still accelerates slowly and does better when I back off a little. I am gathering from all of this that because I set the floats correctly, now I am lean everywhere? Everything I've read says my carbs run rich from the factory and I shouldn't need a bigger pilot, needle should be good in 3rd clip, and maybe 117.5 or 120 on the mains. It doesn't make any sense to me, they ran so good on the 900 with all the same parts, I can't think an extra 112c.c. of displacement can increase the fuel needs that much. I'm not sure if I should put 20 pilots in it, or raise the needles a notch, or go bigger on the mains, or all or none of the above?

I am getting fed up, and was hoping for some advice or direction from those that are wiser than me before I order jets and mess with needles and pull my hair out, etc. Any help would be greatly appreciated. Let me know if I left out any important info or if you have any questions.

Thanks in advance for your help guys and gals!
Ben

There may be some info in the link that helps. Ed

kzrider.com/forum/3-carburetor/585949-po...-a-free-lunch#585949

Before you go any further with jetting check for proper fuel flow. Take the end of the fuel line that connects to the carbs and put it in a catch bucket of some sort. Now turn the petcock on and visually verify that you have a strong fuel flow. Now if it seems slow try opening the gas cap on your tank. If it is slow and opening the cap fixes it, then your cap vent is clogged. If it is slow either way then your petcock or fuel filter (if any) is clogged. If it has strong flow then your issue is in the carbs.

Now there should also be a small screen on top of each float valve in the carbs. These can become clogged as well. To check these, first pull the pivot pin and float out. Next, pull the needle out of the float valve. Finally you can unscrew the brass float valve from the carb body. You should see a small metal screen with a plastic retaining ring on top of the valve. If it is clogged it will be obvious. Carefully remove the screen and clean off the gunk if any is present.

Once you know you have proper fuel flow then proceed with jetting.

Thanks for the quick reply guys, definitely some things to think about. I will certainly check fuel flow. As I ponder on this some more, I wonder if there would be any negative side effects to setting the fuel level back up to even with the mounting flange? At least then it ran good everywhere but wide open. Am I masking a bigger problem or would that be ok to try? I also noticed since the back of my bike sits higher then stock the carbs are actually tilted forward some when mounted in the bike. Maybe that's why I need floats set higher? Thanks again for the help, I am really appreciate it!
Ben

If you set it up to the flange you may end up with an overflow condition. Ed

What happened here is pretty simple. When the carbs were on the 900 the carbs were tuned to run with the float level it had. When you changed the float level by using the wet method (the correct way) you lowered the fuel level which makes the carb run leaner all accross it's range. The symptoms you have now are indicating the carb is running lean all across it's range. I would make sure the float levels are correct using the wet method and tune based on that. The float level is the first thing you should check before doing any tuning. After checking the float levels make only one change to the carbs at a time and run the bike that way you will know what that change effected. Stick with your 17.5 pilot jet, I would go to a 120 main and leave the needle in the middle position. Remember everything is based on float level. One more thing beffore making any changes to jetting make SURE the carbs are CLEAN paying special attention to the pilot circuits. Make sure all the tiny passegways are clear and clean. If the carbs were allowed to sit all winter with gas in the bowls, the gas evaporates and leave a gooey mess that clogges up everything.

Baldy gave you some good advice. The screens above the needle valve only comes on 29mm smoothbores, not the stock 26 or 28 mm mikunis. When checking floats (wet) do not pick the tubes up during this process. Lowering is ok but never raise them. Will give you a false reading every time. Reason being it will push the fuel back up into the feed line and then your guessing. Sorry to intrude.