Join Date: Nov 2015
58TB & Stage IV
Having my dealer installed Stage IV on the dyno 4 times with different exhaust configurations and making the worst 115/116 ever I decided to have a motor built.
RC Cycles disassembled the motor all the way for crank and case boring and the closest they found to any "smoking gun" explaining why this particular bike made such numbers and ran so horrible and the 58 throttle body to CNC port match was questionable but not a smoking gun. 115/116 on the dyno and the slug could barley pull my wife's stock 103.
I viewed dozens of Stage IV dyno sheets by Bob at RC and my numbers were low average but the power even caused Bob to slump every time he made a pass after tuning. Everyone first thought I was nuts until a mechanic rode my bike and stated "this thing has no bottom, middle or top".
I am sold on port matching and the throttle response results. To support my findings 120R motors make an array of numbers from 125-145 and IMO its all in the how the intake/ TB fits up.
With all that said I am just a guy with my own experience. Interested in hearing from guys like Scott. Why would 10 cookie cutter engine kits make numbers and throttle response(s) all over the board?
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2015 113" 125/131
Last edited by Sleepybagger; 11-26-2015 at 01:31 PM.