Air fuel screws having minimal to no impact

  • jstry11
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Air fuel screws having minimal to no impact

03 Jun 2025 19:18
#913317


Pictures are of the spark plugs from one of the cylinders. Both pictures are the same plug just one I wiped off the carbon buildup.  All look relatively similar. However, the bike is clearly running rich,  and the plugs have looked that way even when I had pods and stock jetting and just got the bike to run.  It now starts on command with no choke, nor will it run on choke, or start on choke. It's got mains drilled to 100 and 37 pilots. there's a minor hiccup when twisting throttle from idle to mid range quickly but it responds great afterwords if not aggressive revving it and it goes to about 5k where it breaks up. The air fuel screws do not seem to do anything (ports are verified to be clean). I will be getting replacement pilots to start from stock again but even with pods the bike doesn't seem to want to run lean by the look of the plugs. Any advice here? I know people recommend shimming the needles, but that would make the bike richer in the top end and I'm not entirely sure I need that. I have the stock mains too in the even I need to redrill those to a size smaller than 100. (No air box and I don't plan on getting one)
82 KZ 550

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  • sf4t7
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Re: Air fuel screws having minimal to no impact

03 Jun 2025 21:12
#913321
Why are you drilling out main jets? 
Scotty

1974 Z1A
Yoshimura 987
welded Z1 crank
Andrews 1X Cams
Delkevic 4 into 1
Superbike bars
530 conversion
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  • zed1015
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Re: Air fuel screws having minimal to no impact

04 Jun 2025 04:28
#913333
Unless there are other issues the rich running being unaffected by the air screw indicates that the pilot jet is too big..
AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
www.kzrider.com/23-for-sale/611992-air-c...lide-mikunis?start=0





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