Hello everyone, I have just purchased a G reg Yamaha FZR 400 RR, it currently has R6 downpipes, Fazer (I think) center (without exup valve) and an after-market unbranded can. It has standard Jets and needs up jetting as without baffle it runs fairly rough and will burn the plugs over time. So I was wondering if anyone knew the suitable jets I will need that would be great. Also, does anyone know of any FZR 400 specialists on this forum?

Thanks in advance for any replies

Take it to a dyno and get it sorted there. Because there's no exup it will be running lean low down, but probably not so lean higher up. The lack of back pressure low down will be a ball ache lower down, you'll loose power / torque.
You could try later model a R6 standard can with the exup in, it might work better

Ah okay good idea cheers! Do you know the R6 endcan that has an exup? I cant find one online! Thanks in advance for your reply.

I think it's the latest one, it could be in the link pipe