Backfiring like a good 'un. (Advice please)

[Neosophist]

In order to prepare for the dyno day i've been looking over the bike... (new clutch finally.. can't believe how much quicker it is without a slipping clutch :D) valve clearances / carb balance etc etc.

Anyway, now everytime I gas it to 10k+ rpm and chop the throttle I get really really loud backfires on the overrun (std exhuast system / std airbox.) Engine tuning isn't something im too great at so any suggestions as how to proceed would be helpful.

While I understand that some popping is 'normal' for a decent tuned bike these are like shotgun blasts (although pretty cool i'd like to minimise them)

I've checked everything listed above and it's all near enough standard.

I have the following theories.

Exhuast system letting in air (i.e bad sealing joint)
Pilot screws too lean
Bad Coil / Spark Plug.

Anymore suggestions / hints & tips before I rip it to pieces on Sunday.

Many thanks.

[CMSMJ1]

Leaky exhausts are the usual culprits for these IMO

[hunter]

As CMSMJ1 said leak in exhaust.

[Neosophist]

Ok cool,

I'll take it to pieces tomorrow (^_^)

[Cammo]

Check your pilot screws aren't too rich.

[Neosophist]

Check your pilot screws aren't too rich.

They were 2 turns out originally, i've got them set to 3 turns out now (riiiiiich) just to test and its still doing exactly the same... although has a really smooth idle now!

I can feel a few slight air leaks from the exhaust system so going to seal up the exhaust system properly first and go from there :)

Thanks for the advices.