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Plugs coke up after 1 mile super rich ?

Posted: Fri Jul 05, 2019 10:18 am
by Jacktomomax
Hello all
Bought ZXR400 l2 (1992).bike with this problem, ‘plugs coked up while running’ I have stripped and cleaned the carbs, fitted new main jets 90, cleaned pilot jets. Float heights tried 18mm, 14mm, 11mm same results .mixture screw 1.5 turns.Cleaned plugs , they all spark. I can get it started & ticking over but once you use the throttle it just wants to die, the furthest I’ve been is 1.7 miles all 4 plugs black sooty but not really wet. It’s as if when you use the throttle it just dumps the fuel in the cylinders.
Battery charge at 12.43v but runs flat quite quick when trying to start, new one arriving today hopefully.