Join Date: Sep 2018
Location: Northern Virgina, USA
Good question. As a rule of thumb, small mods to intake or exhaust will make small negative changes to the tune. Large changes will make large negative effects to the tune. Everything from the shape of the airbox to the angle and number of bends in the exhaust pipes are coded into the tune. I talked to a master race tuner at a local race shop about a custom tune for the Bobber. He stated that outside of a tune box (which essentially tricks the ECU), he would have to wait for someone in the race world to "jailbreak" the ECU, which would be unlikely for quite some time.
More to the question of "adverse effects", the engine is going to either run very lean, or rich... and out of tune. The ECU probably won't be able to adjust to such radical changes properly, but that's a guess. You will likely lose HP and torque, probably not enough to substantially neuter the bike. Your pipes, if stainless steel, will most likely turn blue, then black fairly quickly due to excessive heat in the pipes.
This is the typical reaction to changes... I'm no expert on Triumph.
I've spent my fortune on wine, women, and motorcycles. The rest I wasted on everything else.