Manor

Hi everyone, new to the site, so be gentle Just picked up a gleaming 1989 TZR 125 (fully rebuilt) and wow lovely bike. But.............................Errrrrrrrr!! Will only tick over once warm, and then (when blipping throttle) sits at 3000 revs for a few seconds before slowly running down to 1000 and rough tick over. Rides well up to 7000 revs then splutters and pops as it tries to go into the power band, but refuses to budge past 7000revs and 60mph. As i understand it the power valve is pegged open and it has a Ginelli exhaust. I have tried to ring Stan Stephens, but he is on hols till the 30th April. Any thoughts or help would be really appreciated. I live in the West Mids. Cheers, Manor