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My bike still has the slight running issue even after a full service, the revs still hang at about 2.5 k on a closed throttle before dropping down to idle. When on the move there is hardly any power below 4 k. once over 4 k it's like another two cylinders coming into life on the engine. Is this normal?

Oh yeah. The bike is also a bitch to start when cold and needs a fair bit of throttle to prompt it into life.

not normal ..

sounds like blocked pilot jets.

the revs hanging indicates a lean mixture as does the starting trouble.. so could be an air leak, but the lack of power till it climbs onto the needle indicates that rather than excess air, there's a lack of fuel.

see which cylinders take aren't firing from cold (touch the headers .. see how quick they warm up) and check the pilot jet/idle mix on the corresponding carbs.

HTH

Right so I've completely stripped the carbs. I've cleaned all the jets, checked the air screws, they're all set to two and a quarter turns from fully in. The bike now audibly only runs on either two or three cylinders below about 3750 revs and then they all come into life above 4500. All the rubber joints on the carb all seem to be in good condition.

Any ideas? Should I try adjusting the pilot air screws? In or out?

After stripping the carbs in general the bike now runs worse than before.

Thanks in advance.

Depends on which model you have. The L models run in my opinion too rhich with 2 1/4 turns out and I´d put them to 2 or 1 3/4 turns.

Do you now if your enginge got tuned? This mostly goes on cost of power in low sections. For example if you have an lighter rotor/ flywheel you almost can´t drive it below 4k. Just a thought...

Spark plugs checked? Cables from ignition all working fine? Maybe here are issues when it´s cold and it fixes itself when the enginge becomes hotter?

I've got an l9 model. I don't think it's tuned at all. It was completely standard when I got it, rubber brake hoses and all!
I'll try messing about with the air screws later and see what happens.

If anything the problem gets slightly worse as the engine gets hotter however I didn't ride far at all when I could tell the bike wasn't right.

Turns out that one of my needle jets wasn't seated properly. I've sorted that and now the bike is running on all the cylinders all of the time.
I turned the air screws in by half a turn and now I have more power sub 4000 rpm and it's no longer like another two cylinders coming into life above 4000 however I still have the hanging revs at around 2000. I might try turning the air screws in by another half turn tomorrow and see what happens

Weird experiment but I put 95 Ron fuel in the bike and it now runs perfectly ( no hanging revs ) still needs a fair bit of throttle to start though.

I have the same issue cylinder 1 and 2 are producing very low compression and it dies with out throttle. What needs to be adjusted on the carbs? ,

Oz Zxr 400L