Z1 head porting

Mark Wing wrote:

The exhausts are opened up to 2mm under the header pipe to help stop the exhaust pulses coming back up the outside of the head pipes.

Can you elaborate on how this is done plz? is there a ridge or something I cant see in the pics?

Well you'd measure the inside diameter of your head pipe and transfer the measurement to the exhaust ports and open them up to that. your exhaust has a reverberation or pulse that comes back up the outside of the header while the spent exhaust travels down the middle of the pipe. You can't see much in the un ported port, it was taken of an old extra 650 head I have but if you look closely at the ported exhaust you can see a thin dark line around the edge. It's hard to get the pipe centered up every time but it still works anyway.
Mark

What you are describing to me Mark is port matching?

Mark seems to be talking about anti reversion, the exhaust port is 2mm smaller than the exhaust pipe.
IIRC, it's to prevent pushing exhaust back into the cylinder just prior to the exhaust valve closing due to harmonic impulse. AKA exhaust tuning.

Post edited by: wireman, at: 2006/05/16 21:27

#@@!@#$$$$$#$# wrong size pictures!!!!!#@@@@&&&^^^*&^*^:whistle:

Post edited by: wireman, at: 2006/05/16 21:30

yeah these pictures really suck!:S this was after the ports and chambers were coated.and yes these ports are heavily breathed on:evil:

Post edited by: wireman, at: 2006/05/16 22:36

cumbustion chambers opened up for bigger bore,piston coat on chambers.

Post edited by: wireman, at: 2006/05/16 22:38

this is how i do exhuast ports d-shaped flat on bottem opened up on top and sides to match port coming off of chamber.copied from big block chevy exhuast ports seems to work really good.this head came from one of my old 1170 motors i did 10-12years ago ran like a scalded dog well see on this motor.:evil:

Post edited by: wireman, at: 2006/05/16 22:44

cant really see much in picture but extra ribs on front and back of ends where valve cover bolts on have been removed.corners on fins of gpz-j head are chopped off at angle started to round off corners removing sharp angle will look more like suzuki when done,lots more wittling to do and a little more glassbeading before valve job and assembly.

Post edited by: wireman, at: 2006/05/16 22:51

pistons from the 1170 the head came from,i wanted to try the piston coat on the tops and anti friction coating on skirts of these before doing the big motor,the big ones are getting coated now!and yes that 1170 motor was put together with the pistons and rings and cylinders dry 12 years ago,no broken rings no scuffs and bore still is nice and round with no ridge

Post edited by: wireman, at: 2006/05/16 22:53: :evil:

Post edited by: wireman, at: 2006/05/16 23:01

steell wrote:

Mark seems to be talking about anti reversion, the exhaust port is 2mm smaller than the exhaust pipe.
IIRC, it's to prevent pushing exhaust back into the cylinder just prior to the exhaust valve closing due to harmonic impulse. AKA exhaust tuning.

Thanks steell that is what I was talking about.

CrusingRam. Yes that's all I d tell someone to try on their own. Unless you really know what your doing you can rurin the flow by taking material out of the wrong aireas. My head work was done by a profesional engine builder and it's a bit more than just matched.

What I'm trying to say is if you don't have a flow bench or really know what your doing don't start just opening things up as big as you can go like a few guys were saying.