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DannoXYZ · October 2nd, 2018, 11:54 AM

Nice work! Would be interesting to see the gains when you get it all back together!

I'm following in RacerX's footsteps with these mods. Absolutely nothing I've learned from building my own flow-bench to porting numerous Porsche heads at my shop in past 20-yrs applies to these small high-revving engines.

As he mentioned, flow-velocity is key. I sent head from my CBR600RR to an outfit in UK to get head ported. Here's result with narrower ports to increase flow velocity:

CBR600RR ports

And ports from an R1 head:

Also note that flow-velocity is 2nd-order function, so profile should be spherical or parabolic in shape, not cones like original ports (linear function).

October 2nd, 2018, 11:54 AM	#14
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	Nice work! Would be interesting to see the gains when you get it all back together! I'm following in RacerX's footsteps with these mods. Absolutely nothing I've learned from building my own flow-bench to porting numerous Porsche heads at my shop in past 20-yrs applies to these small high-revving engines. As he mentioned, flow-velocity is key. I sent head from my CBR600RR to an outfit in UK to get head ported. Here's result with narrower ports to increase flow velocity: CBR600RR ports And ports from an R1 head: Also note that flow-velocity is 2nd-order function, so profile should be spherical or parabolic in shape, not cones like original ports (linear function). Last futzed with by DannoXYZ; October 6th, 2018 at 01:10 PM.