thunderace jerky in 2nd gear

[ash.y]

hi all recently purchased a 1999 v reg thunderace never ridden a 1000cc before so not sure but when going slow i.e 10-15 mph in 2nd open the throttle it judders / feels like kangrooing if that makes any sense, ive just serviced it new plugs oil etc, i know the exup valve in the exhaust is seized not sure if this could be the case anyone have the same before any advice please? many thanks.

[Fizzer Thou]

I was asked by someone I know to have a look at his FZR1000RU a few years ago because when the revs got to about 3k then engine bogged badly and would not rev through.The first thing that I checked was the Exup vane position and it was seized in the closed position.The owner of the FZR could not afford to have the situation fixed by lots of drilling out of the badly corroded bolts so I just about managed to move the vane around to the fully open position and that allowed him to carry on riding.The carburation at the bottom end of the rev range suffered,but the mid range and top end was enhanced.

On later Exup bikes the rev needle moves one sweep of the tachometer,which indicates that everything is working okay.I am not sure if this check was built into the YZF1000R but it was on the YZFR1 models.

Have a look on www.exup1000.co.uk
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[ash.y]

Ah it is seized open so this would make sense many thanks.