Humour me , I need it!
ZXR750H1 has been playing silly buggers for a week. Runs mostly on cyl 1 and 2. have swapped plugs, and coils [same spec] from a running ZXR400- makes no difference, cleaned carbs 3 times in the ultrasonic tank, done the valve clearances they're all as close to middle of spec as possible. only done a cold compression test but the tricky cyl was 130psi, others 135, 140 and 160 from memory. Remember this is stone cold, not run for 5 days, Haynes manual says 139psi minimum but i would imagine this is a hot figure. Was going to check them hot but not got around to it. 3 and 4 cyl are not really getting warm, headers are cool enough to touch. if I pull the plug cap off either 3 or 4 while it's running i can hear it and see it sparking. If I swap the plugs and leads between 2 and 3 [it's a shared coil] then 2 still runs fine and 3 doesn't. carbs are spotless, diaphragms are good, fuel in each float chamber, have run a static fuel level too, all are correct [4-6mm below mark- see pic] carb rubbers are fine no splits. ignore the fuel pump, it's running of an auxilliary tank in the garage which is gravity fed.
So 1 and 2 run, 3 and 4 don't. If I pour additional fuel in to carbs 3 and 4 it still doens't fire properly, but smells rich. Ive set pilot mix at 1 3/4 turns out on all carbs. Tried richening up 3 and 4, no luck
Carb balance is set and very close
ign pickup coil is set at about 0.4mm gap.
So RH coil runs cyls 2 and 3. 2 runs ok, 3 doesn't. LH coil runs 1 and 4. 1 runs great, 4 doesn't.
anyone know much about the ignitors/CDI box. I'm thinking it's failed. Must be something to do with timing for 3 and 4 I reckon and not a coil driver issue, as both coils give healthy spark to 1 and 2 cyl. And it's audible/visual spark to 3 and 4 with plug cap off.
I'm hopefully going to borrow a CDI/ignitor tomorrow