Porting your cylinders at home

[LC Cnd]

Ran across this DYI on how to port Banchee/RZ by Kevin Herr. Suspect the same info can be applied to RD's. Thank-you Kevin. Here is the link:

https://youtu.be/XEHlK46LgLE

[kpke]

Thanks for that. Seems like good instructions for garage hacks like me. It looks like there's a couple more of his videos I will watch.

[85RZwade]

Deploying die grinder...

[LC Cnd]

Ya, thinking that purchasing that long stem rounded die grinder will be the cheapest performance mod ($45) I'll do besides creating Ali 6mm carb spacers. Love his comment on how this mod will shame diesels on the dunes - I imagine. Jeff is generous with his advise/vids is/are admirable - masterclasses. Noted he made a comment he's contemplating of creating a 611mm motor for a street application - looking fwd to that build if is occurs. Would that even be street-able? Inspired insanity - love it.

[MK]

I mean nobody needs to mark corner radii, but I'm pretty certain that at least 50% of the DIY tuners can't eye-guess raising the ex port 2mm.
That's kind of careless to let people run into fuckin their stuff up.

So my 0.02 ct:
The banshee exhaust port is rather low. Some 30 mm if I recall it right. So raising it 2mm will get you 28mm which is still 1mm more than a 31K with open PV.
But on a 1UA cylinder these 2mm would completely screw up the ex porting to far above 200 deg.

So please do yourself a favor and insert the piston, measure the desired height from the top of the cylinder and use a felt pen to paint a line above the ex port. This will help "guessing" a lot, especially as it's easy to reproduce that procedure on both cylinders.

[85RZwade]

I have Martin's tuning book and continue to refer to it periodically; it has provided good results for me, so I highly value his input here.
Thanks for chiming in!

[LC Cnd]

Located this port mapping guide and mic'd the the top of the exhaust port at 29.51mm (rt) 29.62 (lt). It appears that the spare cylinder(s) photo'd are approximately 0.5mm passed the recommended levels according to the attached map (Erlenbach's). Examining the bottom of the ports there are aluminium lobes that I can remove to match level with the sleeve. The bottom lobes are all I have to remove at this point - sound about right?
(PS - the pitting was caused by the machinist who decided to sand blasts the sides and top before honing out the sleeve. Was not impressed.)

[silverstrom]

That is the kind of machinist you use only once. Were the cylinders full of sand?

[LC Cnd]

Nope - rinsed. Yes, found someone else.

[OldTZracer]

Has anyone got a port map for the 48H cylinder? The are very close to the 31K but not identical...