Altered "Tinking"

The question - I've been hearing the phrase "pipe to your port", and I'm wondering is there any rule-of-thumb or technique to use to figure out the best pipe for your port to avoid buying and trying different types of exhaust pipes. Also, the fundamentals of everything you guys mention about porting, polishing, duration, etc. should apply to four stroke engines too. Right?

The response - Four strokes are absolutely the same. You still want atomization of gas and turbulence in the intake side of things aids in this. And you still want to get rid of exhaust gas in the quickest way possible so smoothing the exhaust side of things helps this. Higher port roofs on 2 strokes = longer valve open period, wider 2 stroke port = greater valve lift. There are all sorts of little tricks that different people do to four-strokes. Curtis Sparks has been known to put a lot of small pits the intake side of the pistons crown to aid in "last minute" turbulence & piston cooling. Different strokes for different folks... The reason that it is always best to pipe to the port is that a pipe can be changed to accommodate the altered porting. However, porting cannot always be changed to accommodate a pipe. i.e. If the exhaust is brought up too high and the later obtained pipe is more of a low-revving torque variety, there's really nothing you can do to easily get the exhaust port back down. Also, numbers and formulas may tell you that the motor should pull its hardest over a given rpm, but after the pipe is tweaked, the numbers can be way off and so this is the reasoning behind porting first - you can never be exactly certain of what you will get. There's just so many (infinite) ways to port a motor that it's impossible for a single formula to work on all configurations. The best way for someone who does not have the tools necessary to port /build pipes, etc. to get the correct pipe for the motor is to let the same company port and pipe the motor. They know where to port the motor in order to get the best benefit from the pipe. However, as Rick (MacDizzy) kinda said in an earlier post, you just have to trust that they are gonna set you up in the best way and you never know if that is happening or not - will they honestly set the motor up the best way they can? However, you may have no choice but to trust them. Porting can be done to the pipe, and in fact, it is probably done more. You just need to know the specs of the pipe and shoot from there. You have to make sure you don't go to far in each step of porting. It can be much more tedious to get perfect, but if you have the patience, it can be done. Oh well, I guess that's it! I am always wanting to chat about this kind of stuff and see the other guys very valued opinions - we are ALL learning here - especially me. I just love this stuff and am constantly in search of better ways, or just different ways, of doing things. I could read tech posts and articles all day long. And sometimes when certain topics come up, it brings out the shine in some very knowledgeable guys. So, ANY time you want to chat about something, I'll definitely join in! Trax310

Date Last Modified: 4/20/99
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