Yes, I don't let any bike out of my shop without front and rear brakes. I just used a side-pull and tied both brakes to a SBP 'teeter-totter' dual pull brake lever. Sweet. I have a 66cc about done here with the same NuVinci shifter and so far it seems to handle the motor. The reason they are so loud is that 4" can muffler only has 1.5" of baffeling in it. There is clamp on 'lawn mower' muffler to add to the stock one that is supposed to quite the SBP Xchamber but like you, I made my own silencer for my 66cc. I used a big glass pack for mine though, and shoved the pipes silencer with the can removed inside the pipe going to my muffler. She's pretty darn quite, and that fatter pipe really lowered the tone. It doesn't sound like Harley, but it doesn't sound like a weed eater either ;-} I look forward to seeing what you rig up.