The Gen 4 was really Paul Yoshimune's engine. It was originally built side-by-side with Lohmeyer's Gen 1 motor receiving everything identical to his except: the carburetur set-up was stock VFR (with airbox and air filter), the harness and CDI stayed VFR, the ignition timing was not adjustable and the cam timing was set to stock.
Once the original Ti rod failed in Lohmeyer's, we changed these as a precaution, upgrading this motor to a Gen 2. Once Lohmeyer's crank broke, we checked Paul's to find it cracked - but hadn't failed yet - so we replaced it with a 2nd Generation CCR Weld-Up as well, now upgrading the motor to a Gen 3 (less the Carrillo Ti rods).
Paul Yoshimune raced the bike for 2 seasons and then sold the bike to Mike Lohmeyer, who then pulled the motor to replace his blown up Gen 3 motor, fitted a stock motor in the chassis and sold that to Kathy Kuwye. The motor stayed pretty much unchanged, except that Lohmeyer converted the ignition to an RVF HRC set-up with adjustable trigger.
The motor was raced by Lohmeyer for a portion of the 2006 season until it, too, snapped the 2nd generation CCR weld-up crank. During the time he was able to use this engine, he earned enough points that, with a few loans of Elrod's bike and the use of Lohmeyer's 400cc back-up engine, we again won the 450cc Superbike Championship and this time earned 3rd overall in Formula-IV. Mark Elrod was able to use his motors to finish 3rd overall in both 450cc Superbike and Production despite crashing and breaking his collarbone at the end of the season.
Bore x Stroke: 57.0mm x 44.5mm
Pistons: REC/G-Force Design
Rings: Yamaha FZR400 (3-Rings)
Bores: Millennium Aluminum/NikaSil Liners
Rods: Carrillo Steel "H" Rods
Crank: CCR Weld-up stock crank. 2nd Generation
Cams: Stock VFR Cams with RLR Slotted Adaptors
Max rpm: 14,500rpm
Carbs: VFR 32mm CV with HRC F-III kit set-up (no airbox)
Race Fuel: VP Ultimate 4 (oxygenated)
DEMISE: Snapped Crank #3