P200 mild exhaust porting question

[Steve]

I would like to open up the exhaust port on my P200E as shown: http://sites.google.com/site/drunkmunke ... ustporting

The page states "The standard exhaust port on a p200 is approx 39mm wide (when measured straight accross)". My question is how exactly is the exhaust port measured to get the 39mm dimension?

I did a paper and pencil port map and get a measurement of 36.5mm when measured straight across when the map is in cylindercial form, and when the map is laid flat I get the 39mm dimension.

Am I just confused by the "when measured straight across" statment?

Thanks.

[H,POOL GADGE]

stay with your port rubbing 39mm, and take port sides out 1.5mm, nice little tweek!!!!

[Bofs]

A set of these are handy for measuring the port size, straight across, in conjunction with a digital vernier

[guygrrr]

A set of these are handy for measuring the port size, straight across, in conjunction with a digital vernier

i'll do a +1 on that.

[shamrockexpress]

A set of these are handy for measuring the port size, straight across, in conjunction with a digital vernier

Is that the tool you got to measure the HOOP!!! on your mod mates

[Steve]

A set of these are handy for measuring the port size, straight across, in conjunction with a digital vernier

I do have both the spring caliper and a digital vernier gage.

But I am still confused about the measurement of my exhaust port. Is the exhaust bore width of approx. 36.5mm on my '79 P200E the stock size? Maybe there is a listing of the stock barrel specs somewhere on this formum or out on the net but I can't seem to locate it. Does anyone know the stock barrel dimensions or mapping for a stock barrel?

Thanks

[jonny snatchsniffer]

run a square down the barrel to the edge of the port both sides and mark at the top of the barrel and measure what you have, my 57mm bore parma is around 39 @70% but i wouldnt go above 65% with wanky p2 rings so about 43/44mm should do ya, just reverse the above process to mark the port width in the barrel and dremmel away, easier with the stub out

[H,POOL GADGE]

good idea that gadge! doing it that way.....