Pretty frustrating ,
76 KZ900 Mikuni VM26SS carbs. This will be the third time the carbs have come off in an effort to correct the plug fouling issue.
I have made the Wired George relay modification to assure the coils are getting full voltage. New viton choke plunger seals . Currently has 15 pilots, and 115 mains . Needles are stock 5DL31 clip in the 3 slot. .Floats set at 22mm. With brand new ND W24ES-U plugs in , it will heavy soot foul the plugs within 30-45 minutes of riding. I've tried hotter heat ranges with no improvement.
Tired, Original engine??
Did you do a Compression check?
Did you do a leak down test with real equipment?
I am done with my KZ stuff, but worked on an old friends KZ 900 this summer.
Did all the basic cleaning, adjusting, few new parts, basic stuff.
And the original pistons and rings were worn out, It needed a valve job and guides.
I told him so! He just kept hoping it would run better.
I got paid, 1/2 of what I should have charged him.
Glad it left my garage!!
Thing had low, uneven compression.
He almost passed out when I told him new pistons & boring - $800 - $1000?
Total head rebuild, valves, guides, springs $500-$600.
To do it right!
I don't know your history of your cycle?
Livin in "CheektaVegas, NY
Went thru 25 of these in 40 yrs.
I SOLD OUT! THE KAW BARN IS EMPTY.
More room for The Old Girl, Harley 75 FLH Electra Glide,
Old faithful! Points ign. Bendix Orig. carb.
I said new points and condensers , incorrect.
Bike has good compression, valves adjustment in spec. It has a Dyna S ignition and Dyna 3 ohm coils. Timing is dead on and the coils test out within spec. I replaced the exhaust with a new reproduction 4 into 4. Stock airbox with new stock paper filter, I've adjusted floats using the clear tube method. I've gone two heat ranges hotter on plugs with no real change.
At one point a while back I thought I was getting close to correcting the issue, but not so. One clue that might be telling is the excessive foulng seems to occur during long periods of part throttle , 30-40 minutes at 45-55 MPH ?