Thanks for all the help so far folks. I have just checked the TPS Sensor iaw Dcocks link. Disconnecting and reconnecting with the ignition on indicated 10000 on the Rev Counter. Adjusted to read 5100 (after spending £13 on a Security Bit set). What symptoms would have that given me and surely the bike would play up from the start? (can't understand how it could have moved the tamperproof screws were really tight). I've ordered a fuel filter just for peace of mind. I will try as you suggest red98 when the weather clears up. Unfortunately the weather isn't great at the moment and the bike is normally stored in the shed but there is no room to work on in there. Cheers John S

hi john....welcome to the stuttering ccccccccclub,well you`ve covered most things....you did`nt mention float needle jet in the bottom of the carbs ,controls the flow of fuel to the float bowls,also worth checking the diaphrams,look for splits and make sure they are nice and flexible and that the needle is a nice smooth action....same symptons as my stutter,have you noticed it getting any worse the more miles you do ?

Hi red98. It was your problems that led me to the Forum. Yes it seems to get worse the more I thrash it. At the start of the ride it seems to be ok. Then after I have started to have fun and make sum rapid progress it will start to play up. I didn't check the float valves, Bugger. But everything was extremely clean. I am going to see if I can remove the Carb Tops without removing the Carbs themselves. I had a nightmare getting them out. I really struggled to get the forward throttle cable out. Any tips on that. Thanks for the quick reply.

Welcome John
 
Do not let the slower colours get you gown as they are all wrong as you have the fastest colour 
 
Love the belly pan, did it come with the bike or did you purchase separately ?
 
Daz

Hi Daz. Thanks for the welcome. The belly pan came with it. I fitted the Beowolf which sounds sweet even with the baffle in. Daren't run with it out as I start at 06:15 in the morning.

I've just joined the Forum and as I stated in the Introduction Forum I found this site when I Google searched with my symptoms. My FZS 600 is a 2003 only 3500 miles on the clock and I've owned it for 2 years. It has a K+N filter and has a Beowolf Can with baffle in. It was fine last year. Because of work and weather I put it into the shed last October.
Brought it out last month and put her through an MOT. Now this is where the fun starts, NOT!!!
When I first ride it there doesn't seem to be a big issue. But after riding for a couple of miles if I quickly open the throttle the bike judders like a misfire and will judder continuously through the rev range. Whilst it is juddering if I back off the throttle slightly and then open it up slowly it will more often than not be okay. But as soon as I try and do a quick increase it bogs down.
I experimented and found from a standing start if I gently eased the throttle up through the revs and gears it will operate as far as I can tell normally all the way to full throttle and redline (and illegal speeds). Also sitting in Neutral after the stuttering has started if I whang on the throttle there is a stutter at the start before it picks up. But same again if I open the throttle slowly it appears to rev ok.
After trawling through the forum and seeing what other people have done here is a list of what I've tried with no success so far :-
 
Replaced Plugs
Cut back 1/2" on Coil Leads and refitted Plug Caps (Screw and coil cable copper look good),
Removed tank and emptied old fuel out. Looked inside an tank base is clean as a whistle.
Removed Fuel Tap and checked filter.
Inspected K+N Filter
Visually checked fuel filter
Removed Carbs and removed Main Jets and the Metal Tube underneath it, Needle Jet? or Emulsion Tube?
Removed the other jet beside it. Pilot Jet?
All where clean with no signs of any contamination.
Inspected Inlet and Air Filter Box Rubbers. No obvious sign of cracks or perishing.
Reassembled everything and put a fresh couple of gallons of fuel in the tank.
Started pretty quickly but a few minutes into a test ride and the symptoms are back.
I haven't taken the top of the carbs off and checked the Diaphrams because I don't know what to check or what I'm looking for.
Would a dodgy fuel filter cause these issues. I have discounted this for the moment because I thought the fuel in the float bowls would initially keep the engine going and then it might fade later if the fuel filter couldn't keep up with demand.
Pump sounds ok when ignition switched on, it pulses away and seems to hold fuel pressure.
I'm getting to the limit of my Mechanical skills and am running out of ideas.
I was thinking of trying it with the baffle out to see if it makes any difference or buying an original paper air filter and refitting the original can.
But I think I'm clutching at straws because it ran fine with this set up last year.
Apologies for rambling on.
Any input extremely welcome.
Cheers
John S