ninjette.org - View Single Post - Crazy japanese racer tinkers with EVERYTHING

DannoXYZ · July 11th, 2020, 01:21 PM

Such awesome tools! Actually measuring cam specs, that's real tuning!!!

I'm not sure which model GPX-250R he's referring to, could it be our '88-07 pregen? Those cam-specs can't possibly match new-gen's. Early '88-93 had massive cam, something like 290-degree duration! That's partly how it was able to make max-power around 12500 rpms with very little torque-drop in upper-rpms. Caused lazy low-end though. The '94-07 pre-gens had tamed-down cams and had much better more civilised low-end without massive upper-RPM hit (like 2-strokes). EDIT: Ah, he's referring to aftermarket Beet cams. yes, those may match early pre-gens. Maybe I should get my hands on set... hmm...

Didn't think removing balancer would do such. It does save about 4bhp on 250bhp Porsche 951 engine. But removing balancer caused issues (aside from vibration), such as cracking oil-pickup tubes going to oil-pump, leaking oil-pan gasket etc. 944-spec racing rules forbid removing balancer-shaft belt due to headaches it caused and goes against goal of cheap clean fun. That and no one wants to be following you when you dump entire 8-quarts of oil on track!

Link to original page on YouTube.

July 11th, 2020, 01:21 PM	#4
DannoXYZ ninjette.org certified postwhore Name: AKA JacRyann Location: Mesa, AZ Join Date: Dec 2011 Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C Posts: A lot. MOTY - 2018, MOTM - Nov '17	Such awesome tools! Actually measuring cam specs, that's real tuning!!! I'm not sure which model GPX-250R he's referring to, could it be our '88-07 pregen? Those cam-specs can't possibly match new-gen's. Early '88-93 had massive cam, something like 290-degree duration! That's partly how it was able to make max-power around 12500 rpms with very little torque-drop in upper-rpms. Caused lazy low-end though. The '94-07 pre-gens had tamed-down cams and had much better more civilised low-end without massive upper-RPM hit (like 2-strokes). EDIT: Ah, he's referring to aftermarket Beet cams. yes, those may match early pre-gens. Maybe I should get my hands on set... hmm... Didn't think removing balancer would do such. It does save about 4bhp on 250bhp Porsche 951 engine. But removing balancer caused issues (aside from vibration), such as cracking oil-pickup tubes going to oil-pump, leaking oil-pan gasket etc. 944-spec racing rules forbid removing balancer-shaft belt due to headaches it caused and goes against goal of cheap clean fun. That and no one wants to be following you when you dump entire 8-quarts of oil on track! Link to original page on YouTube.