Pod filters and header tuning for the street.

I recently purchased my 3rd KZ, a Z1B 900. When I got it running I found it to have the same mid-throttle popping, surging and general lean behavior as the first two I had. After going through the carbs, I found it to be jetted up to 130 on the mains and stock 17.5 pilots. Stock 5DL31-3 needles as well. They had the float level lifted and the clip in the rich position to attempt to make it run right. After consulting the online Mikuni tuning guide and some careful guesswork, I purchased a set of 5L1 needles and installed them yesterday. WOW!!! I used the middle position and dare I say I think I can lean it out just a bit and go down to a 120 and this baby will be puuuurrrrr-fect. The needles are almost the entire throttle band of these carbs. The parts cost me $21.50 from the local Kaw dealer and are actual Mikuni parts. I highly recommend needle tuning prior to any other voodoo methods of lifting needles. The 5DL31 needles were designed to run on real gasoline with limited air and exhaust flow. Good luck and happy tuning!

Thanks for the info, are you on the stock 26mms? Keep us posted on the rest of your tuning.

Stock carbs, yes. The Z1 bikes had a VM28. The 26mm carbs were 76 and up as far as I know. From what I recall, people were using 28 jetting in 26 carbs and having good results, but still need needle tuning. What a lot of people fail to realize is that this horse-piss they are labeling as gasoline now days runs really lean and jetting does absolutely nothing for the part-throttle operation of these carbs. They will melt down at part throttle the same as they will at full throttle. I like just a slight black plume on a quick wrap of the throttle, but not much to start with. Then you fine-tune from there. My 130 mains are way too rich. Going to get a set of 120s.

Ok, here's the update. After going through hell trying to get everything working properly, I ended up at position 3(center) for around town cruising and found that under highway conditions she still wanted to spit back a little. Position 4(second to richest from the bottom) cured that issue almost completely. The 130 main jets seem ok now as well. I found another issue causing one carb to run pig rich and it was driving me nuts! That's when I found the problem(after about half a dozen times into these carbs). One of my needle jets was .025" shorter than the rest!!! If anyone has issues with a single carb rich and you have covered all the bases, hopefully this thread helps you out. Happy motoring all!