looking for porting/tuning help

Discussion in '2 smokers' started by Touring XR, Jul 31, 2013.

  1. joexr

    joexr Banned

    Jan 4, 2011
    The power-valve is a good idea too. Keeping it closed / down , lowers the exhaust port.
  2. Touring XR

    Touring XR Adventurer

    Feb 1, 2006
    Corvallis, or-a-gon
    Thanks for the responses. Just got off the phone with Eric Gorr and intend to send him my top end for porting.

    The 300E is the enduro bike. However, I believe this vintage shares porting with the MX bikes. It came with an alternator, which added some flywheel weight. To add more you need to remove the alternator rotor, so it ends up being a wash.

    I have had the power valve governor shimmed shut. It helps, but the transition into the power band is still pretty brutal. I haven't measured the porting but I suspect from the behavior that the exhaust timing is too long as is the transfer timing.

    For the price of a porting package, plus what I paid for the bike, plus my distate for riding orange, seeing what Eric can do with the welder, mill and some epoxy is worth it.

    Plus 1 week turn-around.

    I'll report on the completed package.

  3. cc-rider

    cc-rider Adventurer

    Apr 15, 2007
    You can make your exhaust flange longer (maybe an inch) will move the powerband up to a higher RPM and but hit a harder.

    On one of my bikes my longer tuned put me on the pipe at 6500 rpm's instead of 6000.