I have an f4i with a power commander 3, 1 down front, and a yoshi slip on. usually, my bike runs perfectly crisp but backfires pretty bad when engine braking. Other than that, feels like it's suppose to.

Over the weekend, i cut my yoshi in half and did the clean air mod.


I cut the yoshi and test drove, i felt a bit of a hp pick up around 5k rpm, but lost torque on the bottom. Is that normal? anyway to get the low end back or that the consequence of the louder pipe?

After doing the clean air mod, pretty much had the same effect, though hard to tell. Little mid range power gain, slight bottom end tq loss. Doing the clean air mod, it seemed like i just plugged all of the crank case vents into each other, doesnt that close the loop and not allow any crank case ventilation? if not, how is the crank case being ventilated? I noticed my bike ran a slight bit hotter after doing this, went from aving about 185 cruising, to drifting between 200-210 cruising, though im not ruling out my staying at higher rpm to find the sweet spot on the sound more often wasnt the reason. that normal? Bike also still backfires on decell after clean air mod.

last question, what is this?

 

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