Just tick over at full throttle opening ?

[Big1965bloke]

Hi Guys
I currently race a 1987 FZR Genisis in the New Zealand Post Classic Series and the bike has done me proud.
Last season I had trouble with the bike jumping out of 3rd gear so I removed the engine and had the gearbox undercut.
Since rebuilding the engine I have had the following problem,
The bike will start and tick over ok and sometimes run ok except for poor running in the midrange but then when you stop it will suddenly refuse to rev and on a wide open throttle ie with the throttle to the stop the bike just ticks over. You can sometimes coax the engine in to life by gentle keep twisting the throttle in the mid part of it's opening.
This is what I have done to try and fix the problem,
New battery, new fuel pump relay, exchanged the pick up from my 750, tried the ecu from the 750, cleaned the carbs, checked the diaphragms, checked the fuel cap to make sure the breather is clear, checked the fuel tap, removed the reserve extension pipe in the fuel tank and replaced the spark plugs.
If anyone has any idears please feel free to help me out as I am about to give up.
Brambo

[Stig]

Off the top of my head It sounds like fuel starvation. Is the breather trapped

[taggy]

coils?

[yamaha_george]

Hi,
are you running the original air box ? if so check the rubbers are seated properly also the carbs seated properly check the seal of the various rubber parts on the inlet with a spray of quick start when the engine is just tiking over if the revs pick up on their own you have a cracked rubber.
If you are using pods on the carbs are they "spaced" off the carbs at the correct length?