need good bike mechanic

[ozzie9962]

im having problems, my bikes missfiring at 4000 revs its been on dyno and they said its running rich ive changed plugs air filter put standard cans back on, it sounds sweet till you hit 4000 revs, it doesnt stop it just misses tick over sounds ok im lost ,cash waiting to fix problem yorkshire area.telephone 07810792337

[Pete.L]

Sounds like it's been jetted at some time.
Check the needles, for std cans they should be set at the forth ring and running 170 mains.
If it's not jetting you might just have a blockage in the carb somewhere so a strip and clean might be in order.

Pete.l