what exaclty is polishing and how do they go about doing it? thanks

 

You're talking about a port and polish, right? My understanding is that you match your intake/exhaust gaskets and jug so that they match up exactly. Basically you set the gasket up there and then grind away until they match. Then you polish away any imperfections so that it's perfectly smooth. That's it in a nutshell -- I'm sure that there are some experts here that can elaborate much better.

 

yeah i was refering to port and polish, i asked about porting on the yamaha forum awhile back. so basically what you are saying is that all a polish is, is smoothing out the ruff spots out a port job? thanks

 

Polishing is done to the inside of the exhaust ports. This gives a smoother surface for the exhaust air to flow over. You should never fully polish the intake. The intake air/fuel mixture stays more atomized and actually flows faster over the slightly rough finish.

"Gasket Matching" is where you make sure the ports line up perfectly.

To polish, you do it exactly like you polish any aluminum. Take a medium grit sandpaper and knock down the roughest edges. Then go with a finer paper. Keep going until it starts to shine. I usually finish with a 4000 or 5000 grit. It usually goes 180, 300, 800, 1000, 1500, 2500, 4000, and if I am really wanting a shine, 5000 to finish. Takes a LOT of time and it is hard to find 2500 and finer paper.

Hope this helps.

 

Exactly Alky. To add to that post, the smoother you get the exhaust or getting it as smooth as glass will keep carbon from sticking to it also. You can basically gasket match the exhaust gasket, but in reality that will yield nothing in comparison to the actual grinding and/or porting of the cylinder itself. Most of the time exhaust ports get widened, raised in some instances, and intake and transfer ports get worked over as well. If you do not have the necessary tools or knowledge, it is really better to have someone who knows do it for you. As little as 1mm (.040) can make it or break it in some instances. not alot of mess up room to work with.Bubba

 

would polishing the inside of the cylinder walls give any results?

thanks alky for the help and bubba i dont have the knowledge but it something i want to learn. thank you for the help as well.

 

no, dont polish the transfers

 

just the exhaust, nothing more

 

thanks dabeechman

 

A good thing to do id to remove any sharp edges inside the intake and exhaust area if you can reach them. Think about air flowing all through the intake tract, up through the transfers, and out the exhaust. Any mis-match of liner and aluminum, or very sharp edges, or clumped up "goombas" as I like to call them need to be addressed. Your engine is simply an air pump and you want it to be as effective as possible. I could write you a book on formulas and such for porting, but for the novice person just give everything a good cleanup, polish the entire exhaust port as slick as possible, and leave the intake areas as a rougher texture to keep the fuel atomized. Give edges a round edge instead of a shap edge. That's about all I can do to help. If you take some time with it you actually will be able to notice a difference.Bubba