cbr250r dents in extractors

[Static]

today i was bring my bike back onto the road off a curb and it hit and dented 2 of my extractor pipes its a 4 to 1 exhaust system and its dented the bottom 2 pipes, now theres a tapping sound when i ride that gets faster as the bike revs so i have 2 questions would the tapping be because 2 of the cylinders arent clearing as fast as the other 2 and is there any way of fixing it

[What?]

The tapping is because the header pipes are double-walled. The dents in the outer tubes will be connecting with the inner tubes.
The pipes could be fixed by drilling into the dents, inserting a screw, then pulling the dents out whilst heating with a gas torch. As you had to ask, I would assume that this is not something you are going to do yourself...
And if your headers are nice, shiny chrome plated, they won't be after this treatment.

[imdying]

Can anyone else confirm that? (that cbr250 headers are double walled) Seems unlikely?

[Static]

yea so i took it to the shop today and they thought it may be an exhaust leak round the gasket so when it cools down i need to try tighten all the bolts first and if that fails replace the gasket so i might try that first

[What?]

Can anyone else confirm that? (that cbr250 headers are double walled) Seems unlikely?

Could be right - if they are chromed, they will probably be double-walled, but black painted or stainless, probably not. If the pipes are after-market, almost certainly not double-walled.

If the pipes have had a good whack from below, it could well have damaged the port gaskets, or even snapped a stud (less likely, but not impossible)