RZ350 Intake Porting

Since there’s plenty of guys out there that would like to try their hand at porting their RZ350’s. Here’s
 what I do on the intake side. Transfers and Exhaust take some skill but here’s some intake work that
 most guys can do on their own and feel pretty good about what they’ve done.
Remember Go slow, you can always take more off, putting it back isn’t quite so easy…

On US cylinders I would usually simply measure “A” and transfer that measurement to “B” to set the
 intake port floor. This sets the intake floor at 102.5mm from the top of the cylinder. You can safely go 
as far as 104.5 which comes stock on 1UA cylinders but pay attention to distance “E” you don’t want 
to weaken the sleeve in that area too much and the lower you go with the intake the less you can safely 
unshroud the base of the transfers in that area. The intake roof “C” can go as high as the stroke, plus
 .5 deck height, plus typically 10mm to support both rings for a height of typically 64.5 from the top of the 
cylinder though usually 70 was enough to feed the majority of the hottest of engines for me. I would 
thin the bridge “D” to 6-7mm and use 10mm-ish radiuses on all the corners. I never went much wider 
because these dimensions seemed to work very well and the whole idea is to make each passage just 
big enough to do the job, not to small, not to big, just right for the HP target your aiming for, this keeps 
port velocity up which is a very good thing. Don’t be afraid to give the intake ports a nice chamfer too 
it only aids your airflow as the incoming air tries to go down, up, and to the base of the transfer ports. 
Do not knife edge the leading edge of the intake bridge, give the bridge a nice rounded leading edge. 
I use double cut carbides then cartridge rolls in 80 & 120.

Take it slow and enjoy. Happy porting!