Kawasaki ZZR1100 C3(1993). Bike starts first time every time and appears to rev freely whether at constant revs throughout range or blipped. Bike revs to about 3 thousand revs on full choke - I am sure it used to rev higher but not sure. Bike rarely smokes once warmed up. Problem only appears on the road. Bike pulls away as per normal but once rolling appears to hesitate sometimes at worst to the point where it appears to want to shut down - as if run out of fuel. On those occasions restarts and continues down the road lurching no matter what throttle position but as you can imagine rarely at full throttle. Only modifications are K&N air filter and Motad exhausts.

I replaced fuel filter last night and once float bowls emptied started bike and held fuel pump to find out if it was operating - not very scientific but helpful - it appeared to be operating fine. Since tank was off also pulled plugs which were all a great darkish brown. Fitted new plugs. As a precaution also fitted alternative coil caps. Did not help at all but you have to try. Yes 18 year old carb screws - nightmare - I had this feeling that I would have to resort to stripping them but I guess I was hoping for a fuel starvation issue or even an intermittent ignition fault. I replaced fuel filter last night and once float bowls emptied started bike and held fuel pump to find out if it was operating - not very scientific but helpful - it appeared to be operating fine. Since tank was off also pulled plugs which were all a great darkish brown. Fitted new plugs. As a precaution also fitted alternative coil caps. Did not help at all but you have to try. Yes 18 year old carb screws - nightmare - I had this feeling that I would have to resort to stripping them but I guess I was hoping for a fuel starvation issue or even an intermittent ignition fault.

This has done much to guide me in the right direction - I had my suspicions - confirming my fears. This has done much to guide me in the right direction - I had my suspicions - confirming my fears.

Hi just to add a couple of pieces of info to the mix. Removed tank and airbox and ran using remote fuel supply in garage. Adjusted choke cable so that now full choke is 4 thousand revs ish and ran bike to eyeball vacuum slides and they all lift together when throttle opened - carbs close to balanced. Hi just to add a couple of pieces of info to the mix. Removed tank and airbox and ran using remote fuel supply in garage. Adjusted choke cable so that now full choke is 4 thousand revs ish and ran bike to eyeball vacuum slides and they all lift together when throttle opened - carbs close to balanced.

Just been flushing the float bowls using temp fuel source at same time as opening drain on each carb in turn - no signs of debris which was a surprise. Each carb had fuel in them and flow continued which at the very least points to good floats and needle valves, There has also been no signs of carbs overflowing at any point. Vacuum slides all move in unison as do throttle flaps - reasonably balanced carbs at least by eyeball plus vacuum diaphragms in good condition.
I may have found the problem though - there does not appear to be enough fuel in the filter - it barely reaches half full. Vigorous tapping of fuel pipe and filter normally sorts this - used to do this with my old ZX10s and would not try and start unless it was very nearly full - saves battery if bike has been left for a while. If float fuel levels decrease needle valves open as float lowers, fuel pump then pums fuel from filter if there is not enough available then might pump air. This might explain why bike pulss away fine then starts stuttering and lurching sometimes pulls or missing feeling and ocasionally feels like it is going to die as if running out of fuel - petrol tank tap or tank filter blocked probably? Just been flushing the float bowls using temp fuel source at same time as opening drain on each carb in turn - no signs of debris which was a surprise. Each carb had fuel in them and flow continued which at the very least points to good floats and needle valves, There has also been no signs of carbs overflowing at any point. Vacuum slides all move in unison as do throttle flaps - reasonably balanced carbs at least by eyeball plus vacuum diaphragms in good condition. I may have found the problem though - there does not appear to be enough fuel in the filter - it barely reaches half full. Vigorous tapping of fuel pipe and filter normally sorts this - used to do this with my old ZX10s and would not try and start unless it was very nearly full - saves battery if bike has been left for a while. If float fuel levels decrease needle valves open as float lowers, fuel pump then pums fuel from filter if there is not enough available then might pump air. This might explain why bike pulss away fine then starts stuttering and lurching sometimes pulls or missing feeling and ocasionally feels like it is going to die as if running out of fuel - petrol tank tap or tank filter blocked probably?

This was something you mentioned earlier so thanks for that - it is easy to take things for granted plus not as easy as old ZX10s to eyeball filter with tank fitted. I will let you know if this sorts problem - bike runs poorly even with minimum throttle. This was something you mentioned earlier so thanks for that - it is easy to take things for granted plus not as easy as old ZX10s to eyeball filter with tank fitted. I will let you know if this sorts problem - bike runs poorly even with minimum throttle.

It has probably never been cleaned out in all of its 18 years but it would explain why filter does not fill even manually and why all is well in the garage but once fuel needs increase dramatically then problems. Will not be ready to sort until new seals arrive - thanks. It has probably never been cleaned out in all of its 18 years but it would explain why filter does not fill even manually and why all is well in the garage but once fuel needs increase dramatically then problems. Will not be ready to sort until new seals arrive - thanks.