porting and polishing.

[ruthlessxbeastx]

can this be done at home or is it better for a professional to do it?
also what are the pros and cons of getting this done?
thanks

[nutz4sand]

Its as easy to mess up the flow or likely easier than to make it better.

Unless there is a MAJOR casting flaw jutting out into one of the ports passages you stand a good chance to interrupt the flow patterns and could make it worse. The air is moving through those passages at near 300 miles and hour. Imagine that and how it will be moving with fuel vapor in it.

Lotsa people (myself included) have told ourselves we can do it. Sometimes you get lucky and open them a little right and sometimes a "home porter" makes it worse.

Polished intakes are not ideal either. They cause fuel to puddle. You want a minutely rough surface to keep the air agitated and the fuel atomized in it as much as possible.

[bdkw1]

Originally Posted by nutz4sand

Polished intakes are not ideal either. They cause fuel to puddle. You want a minutely rough surface to keep the air agitated and the fuel atomized in it as much as possible.

Ever see a puddle in a 300MPH wind? Polished intakes are not a problem. If roughing up a port a little makes you more power you had to large of a port to begin with. All the surface texture does is create a boundary layer which reduces flow slightly. Also, polished ports transfer less heat making for a denser intake charge.

[nutz4sand]

I have seen more to say polished intakes are worse than textured. I have seen a documented 327 v-8 Chevrolet Normally aspirated making in the 750 HP range due to textured intakes that they could not get with polished.

[MC@ Performance Fab]

Porting is black magic dont play with them. Also on any of the crotch rocket bike motors the last thing you would want is larger dia ports.

[evan]

You can alter the piston on 2-smokes to play w/ the concepts. A $60 piston miscalculation is better then a $300 cylinder miscalc.

[ruthlessxbeastx]

alright well so porting and polishing is not the best thing to do? so now what is your guys opinions on boring out a cylinder? can that be done at home? cause i know that adds power! well if you guys have any motor mods that can be done at home or cheaply that increase power,torque really just make difference throw me ideas!
thanks!

[nutz4sand]

Only bore to get to the size you NEED to get the next piston size in it!!!!

Boring to get a bigger piston on cylinders you have trouble finding is ruining them.

The tiny bit of power you get is not worth taking a cylinder out to its biggest bore as soon as you can.

250's are nearly as fast as they can be safely driven anyways with no rear suspension. Unless you ONLY drive on super smoooooooth places.

[ruthlessxbeastx]

ya that is true i used to have a tecate 4 with the 330 big bore which was a huge difference.but very costly, so any ideas on any other upgrades motor wise? maybe a way to keep cooler? also gauges i want to get an egt but they are very expensive and i was curios if a car one would work? since they are cheaper and also will a car tach work for the odyssey?

[nutz4sand]

A simple exhaust pipe if you can find it and proper jetting will go a long way. As will a good breathing airfilter (Not K and N! At least not for me). If the piston and rings/cylinder are in good shape a small bit of shaved head can help but to much will turn a fun machine into a problem child. Being aircooled you do not want to go tooo crazy. But it should be close to 140-150PSI. Higher is asking for trouble in aircooled IMO.

If you can find a person with a reputation who does porting they might clean the ports up a tad for reasonable.

I am not sure if you can do much with the clutches on those.