air mixture screws

Has anyone ever heard of closing the air mixture screws on a 1000. Even with them closed, still getting carbon deposits on the ends of all four plugs. Will going to a higher heat range plug help to solve this. If the screws are turned out even 1/4 way, bike will bog down and "spit" from the carbs. Has Champ N3C plugs now. That is what the Kaw dealer told me to put in.

Personally, I think Champion spark plugs are useless.

Can you add your location and bike model to your signature line? And then tell us what other mods your bike has, and it's general condition? The more we know the better the help you get:)

Do you have a manual, even an owners manual will get you started. What plugs does it suggest? Generally the air screws are dealing with the lower rpm range. If you have carbon fouled plugs it could be carbs or electrical.

List your bike year/model and location in your signature. You can edit these by going into your profile.

As far as Champion spark plugs being recommended by a Kaw dealer, I would not put much faith in this recommendation. Your bike uses NGK or ND spark plugs as specified in the factory shop manual. In particular, NGK B8ES is the correct plug and heat range. Champions, Autolites and other plugs do not cross reference closely.

Second, Before mucking with the carburetors, did this dealer suggest adjusting the valves? Did he suggest timing the ignition? Did he suggest new coil wires/caps and most important, did he measure the voltage going to your coils? Therein most likely lies the source of the "plug fouling" which is most likely poor combustion due to ignition issues than it is carburetion issues. At least your Kaw dealer is speaking to you as almost none will work on a bike model older than a 1996 but the bad news is, they have little experience working on vintage bikes and will just end up becoming a money pit if they do work on your bike.

Oh yeah, most KZ1000s had pilot fuel mixture screws located on the bottom of the bowl side near the intake manifold and didn't have air screws which are typically up on the sides of the carbs. ID your carbs carefully to ensure they are the originals or you will certainly get some bad jetting advice if it gets to that.

Post edited by: wiredgeorge, at: 2006/05/16 08:57

valves have been adjusted, timing done, 12.8 volts coming out of coils, new plug wires, air screws side of carbs (think they are 26 mikuni's, but not at home so cant look right now). person at work suggested going to a higher heat range for the plug because of the 4-1 racing pipe on the bike (i did not put this on)

I suggest you put your bikes year in your signature as well... the reason? The 1977 KZ1000 had different carbs than the 1978 which had different carbs than the 1979 which had different carbs than the 1980. ALL YEARS USED SOME SORT OF VM26. In 77, for instance, the VM26 was still relatively rich air/fuel mixture across all ranges of operation but they went to pilot screws as these have more adjustment to the pilot air/fuel mixture. In 78, they went lean... by the end of 78, they came out with the A2A model and it was REAL REAL lean. In 79, they used accelerator pumps to shoot some gas into even leaner mixtures so the darn bikes wouldn't backfire. They were also using VM28 pumpers on some models and VM26 pumpers on others and the jetting varies by model with the LTD type jetting somewhat tuned for mid-range rather than horsepower. In 1980, the carbs were much the same as in 79. Only one model of VM26 that came stock on a KZ1000 had air screws and it had an accelerator pump I believe. Most of the VM26 carbs I know of that have AIR SCREWS (on sides) were from the 76 KZ900 (and the 77 KZ900).

To diagnose your issues, how did you measure the 12.8 VDC at the coils? What is your current jetting (pilot jets? Jet needle type and clip setting? Main jets?)

used voltage meter when bike was on to get the 12.8, when hit starter button dropped to 12.3. main jet is a 140, clip setting is on the fourth from the bottom (this needle has six clip settings), does 15 on the pilot jet sound right? i believe that is what it was. this carb does have the accelerator pump on it. there are no holes, tears or other problems i could see there either. looks like new inside.

I had the same problem I used b6es ngk (champion plugs are for wheelbarrows:laugh: ) and lower octane fuel and that seemed to fix my problem. My plugs looked like they were dipped in soot before:blink:

Post edited by: 2bskor, at: 2006/05/21 08:05

Read the coil powering article in Filebase. The way you checked voltage doesn't help diagnose your issues. You have a Dynajet Stage 3 kit in that bike, by the way.