www.zxrworld.co.uk

I recently bought an 1994 ZXR 400. It starts and runs fine, can be red lined while parked. After driving a few yards it starts running bad, after another 200 yards or so it wont go over 2000 revs and eventually cut out. Can be restarted only under full trottle and will only run at 2000 revs under the full trottle. It is then necessary to clean the plugs to get the bike to start again. I have cleaned the carbs, air filter etc, replaced battery with a new one, bought new plugs. Any help please!

Did it do this before you replaced/cleaned everything?

yes, full service made no difference. I bought the bike without driving it.

oh dear! Sorry to hear that! Hopefully youve not paid too much!

When you take the plugs out to clean, what do they look like? If they are soaked in fuel then its probably running massively rich. Sounds like its bogging down under load which is another indication its running rich, except this seems quite severe. What did you set the mixture screws at after cleaning? And what jets are you running?

whip off the carbs, clean em, blow em thru. sounds like the floats are not reseating. too much gunk in there baby.

Guys,

Eventually got someone to do the carbs, they took them apart, reckoned they looked pretty good, carried out some measurments which they said were just about right so problem not there. Checked seals, they were fine, washed the air filter in petrol, changed the plugs I put in two weeks ago, changed the seal in the air box, put it back together and drove it. Went fine for about 3 miles then back to the same old thing, running like s**t, barely got me home again at a crawl. Plugs were wet again. One thing I did notice is the ignition coil is not bolted in, just held in with plastic tie wraps, it looks ok but as its not bolted in mayber previous owner changed it? Would this effect the bike as described above?

I have a crashed ZZR400 of the same year, are some electronic parts the same, was thinking I could switch some parts to eliminate the problem?

Any ideas other than buring the bike would be appreciated.

are you getting sparks from all 4 plugs??

Yes, getting sparks but thought maybe its intermittent when driving..

Is there water in the fuel?

No water, changed the fuel that was in the tank twice already.