1983 KZ1100D2 Tuning Question

Hello,

I have been working on getting this bike on the road. The bike is all stock except for having the emissions crap removed and the crankcase breather no longer goes into the air box. I installed new carb holders, new air box hoses and have the complete stock air box intact. just cleaned and rebuilt all 4 carbs. I have the stock exhaust in place however it is slightly modified. Three 1/2" holes equally spaced have been drilled through the end plates. I have the #40 pilot jet and a 120 main. by the manual I should be running a #117.5 main.
I adjusted the air/ mixture screws to get the best stable idle. Then I synced the carbs and it is running ok. however it is really rich. the exhaust gases will burn the eyes at idle but there is no smoke. when the throttle is opened I get a good cloud of black smoke. is this all being caused by the oversized main jets. or do I need to look into smaller pilots as well. with the cost of jets, I would welcome any subjections as to where I should start. I would like to avoid spending 100's of dollars on jets if it can be avoided.

Thanks in advance for the help.

When I first started tuning bikes (beyond stock engines), I found getting the carb jetting and mixture settings correct nearly impossible until I was taught some basics by my vastly more experienced mentors and co-workers:

1. Carbs have to be clean and in good condition - no blocked passages, vacuum leaks, worn out or incorrectly modified parts, etc., otherwise you are going to chase your tail in circles. I've had a few sets of Mikuni BS34's that just plain refused to work correctly because the throttle plate shafts were slightly worn. Those have to be my least favorite stock carbs to work on BTW. (I much prefer the Keihin's on my CBX's)
2. Problems caused by exhaust modifications are less problematic and easier to correct than intake modifications...
3. The float levels have to be close to spec. before you should attempt to tune the carbs. Not too bad if the carbs still have the original floats, float valves, and seats in the original positions and they work properly (the little spring plunger in the float needle has to be in top shape and working perfectly), and haven't been tampered with before. If that is not the case, then you could be in for some sweat and tears. If you aren't replacing the float valve assemblies with all new parts, this step can be tricky and frustrating, as the carbs have to come out and apart many times to get it right, unless you are experienced / good at it, have some special tools, and maybe posses a reliable rabbit's foot...
4. Idle up to 1/4 throttle operation is mainly the job of the idle circuits - the idle mixture screws and the pilot jets, so only adjust those if the problem occurs in that range. Marking the twist grip in 1/4 throttle increments helps when you are out for test rides. Most of the time, only the pilot screws need adjustment. The idle circuits continue to be a part of the fuel equation to full throttle, but less and less important as the throttle opening increases beyond 1/4.
5. The slide, needle jet and needle position are the main culprits from 1/4 to 3/4 throttle...
6. The main jet is the key above 3/4 throttle. Read up on how to do a "plug chop".
7. An old rule of thumb goes "if you are having a problem when you are asking the engine for power, you are to rich...if you have a problem when you aren't asking for power, you are too lean".
8. Fuel mileage is also a good indicator - you should get as good or near what the bike was originally rated for in road tests of that model, if you can find them. The factory tuning settings were generally the best for overall performance within the limitations of the emissions requirements of the time...mostly the factory idle mixture settings were on the lean side, but everything else was much closer.
9. The carbs must be synched each time adjustments are made, and all should be within 3/16" on the mercury sticks for best results.
10. There are a few different electronic air - fuel gauges you could install permanently in the exhaust system. These handy gadgets can make carb tuning much easier and quicker...but unless you install one in each header pipe, you still won't know what is going on within each cylinder...
11. A infra-red thermometer can help by comparing the exhaust pipe temperatures on the head pipes at idle on a warm (but not overheated) engine, if you take readings within an inch of the exhaust ports. You must use a high quality meter, held at the same distance away from each head pipe, and take readings at the same spot on top center of the downward bend on the head pipe. The inside (cylinders 2&3) pipes might be a little (10 deg. F.) warmer, but all should be pretty close to one another (+/- 10-20 deg. F). A hot pipe is LEANER than the rest, a cool pipe is RICHER.
12. A large electric fan aimed centrally at the front of the engine can provide cooling air similar to going 25 mph. Using one lets you tune longer without fear of quickly exceeding safe operating temperatures.
13. Don't ever attempt to tune or diagnose an overheated engine - again, you will be going in circles...

Oh, sorry, I got side tracked...

Air cooled Kawasaki's have always had stinky / dirty - unburned hydro-carbon (rich) smelling exhaust, in my opinion. I hate starting one in the shop, especially in winter with the door closed! The DFI GPz1100's were better, but still stinky compared to the contemporary CB1100F and GS1100's.

Just a part of the less than ideal (under all conditions) combustion chamber inherent in the 2 - valve "hemi" engine design, I think.