ZXR 750 twin cylinder!!!!

[zepp]

Now that I off the diving for a while due to ear problems, I have decided to dig out my old, battered but sort of loved Kawasaki ZXR bike out. It hasnt run now for 18 months due to mice making a meal out of the ignition leads and fuel pipes ...anyway after buying new leads, plugs and plug caps, together with a new battery, the thing only runs on two cylinders!. I have ruled out carbs as I have now had three sets on it and cannot be the coils as it is cylinders 3 and 4 that wont fire (cylinder 1 uses the same coil as number 3 and 4 uses the same as number 2) I have checked the compression and all are similar, actually number 3 cylinder is the best out of the four.
If this had have been me decanting pure o2 I would have had an almighty BANG since I have the fuel, oxygen and and ignition source!!! Sods law eh when you WANT to have a bang!!!!!

Any help please or anyone had similar?

[Woz]

Pull the plug out and turn it over with the plug earthed on the outside of the engine. If you've got a spark, fuel and air and it's still running on 2 then throw it away and get a Honda.

[Enzo]

Zepp, as per Woz's advice, check for spark first. If there is a good spark, check the plug after the engine has been cranked a few times. If the plug is dry - check for correct fuelling.

Good luck.

Enzo

[zepp]

Originally Posted by Woz

Pull the plug out and turn it over with the plug earthed on the outside of the engine. If you've got a spark, fuel and air and it's still running on 2 then throw it away and get a Honda.

Cheers Woz. Yes I have done all that, all sparks are good, fuel is there (can be seen been sucked in through the carb bodies) oh yes and deffinatly got air. A bit of a wierd one this!!!

[David M]

Have you tried switching the plugs from the cylinders that run to the one's that don't ?
a plug that sparks outside the motor might not spark under compression in the motor
as for buying a honda don't be silly
i had a zxr 750 and it was more than a match for any honda

[zepp]

Originally Posted by David M

Have you tried switching the plugs from the cylinders that run to the one's that don't ?
a plug that sparks outside the motor might not spark under compression in the motor
as for buying a honda don't be silly
i had a zxr 750 and it was more than a match for any honda

Yep, done that....

[David M]

Are the plugs wet ?

[jamesp]

have you tried runing the coils on just the duff cylinders, with the good ones removed? coils can break down and the output not quite be up to scratch.
check the carb mounting rubbers on the duff cylinders, cracks or bad fit could be an air leak on the inlet side which would stuff things up.

My GPZ 900 has been stood for five+ years, I`ve got this to look forward to......

[recurve]

Are all the chokes operating fully? My old CX500 had the chokes linked with a very weak spring, and the least bit of crud stopped the one opening. Use the old trick of warming up the plugs on a gas ring, they might be a bit carbonised and fail under compression.

As a side note, I have been on the verge of getting my Guzzi on the road. Saturday was to be the day. Pressed the starter, engine spins but......nothing. Check the fuel injection pump.........nothing, check the spark plug.......nothing. Hmmmm, perhaps damp has got into the EFI unit; pull off sealing tape and there is a bit of damp on the rubber plug underneath....hmmmm thinks I. Remove rubber plug........ OH FCUK.... it is full, yes FULL of water. Bu99er sod and dammit. At least one fried chip (no wisecracks here), and who knows what other damage. Bl@@dy weather!!!! (bike lives outside). Now trying to source a new EFI computer.

[zepp]

Originally Posted by jamesp

have you tried runing the coils on just the duff cylinders, with the good ones removed? coils can break down and the output not quite be up to scratch.
check the carb mounting rubbers on the duff cylinders, cracks or bad fit could be an air leak on the inlet side which would stuff things up.

My GPZ 900 has been stood for five+ years, I`ve got this to look forward to......

Mounting rubbers are good...seriously this is a strange one, the thing should run!!!