Depends what you switched from, anything that allows the bike to breathe better will give you small increases to a certain extent. If you had more restrictive pipes on with the TOR tune you probably had too much fuel being delivered with less flow robbing power. Then you go back to the TORs with better flow now able to burn the fuel being delivered and evacuate the combustion chamber so you would notice a bigger increase than going from a proper tune with restrictive pipes to a proper tune with more open pipes.

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