Basic Cylinder Tuning

[stred-aerox]

Hi, i have the stage 6 sport and i will be doing the piston rings soon so i might as well do some tuning.
My question is what basic tuning can i do that is easy, apart from exhaust port?
Also is it o.k to do it on an aluminium cylinder, will the plating not break off?
Any pictures if possible.
Thankyou.

 

[Aidix]

Besides modifying the exhaust port there is nothing usefull that can be done without the aid of a mill.

Ofcourse there are a lot of useless things to be done like polishing the hell out of everything untill it shines like the bathroom mirror, giving the two transfer port dividers a V shape, and reducing the foot till there's hardly anythign left to support the piston etc... But you won't notice any gain.

The nikasil plating is very fragile, especially in Athena/Stage6 and (even worse) Airsal kits. It all depends on using the right tools and technique. You'll have to experiment a bit to find out what works best for you.

The rougher the tool, the easier it is to damage the nikasil.

The pink ones work best. None of the Dremel type tools (brown/grey) work, they're simply too rough. The pink 'edelkorund' tools by Proxxon are quite ok.

 

[stred-aerox]

ye thanks. I have a high speed dremel (33,000 rpm). What are the pink ones made of? I was going to get a dremel diamond cutter, is this no good?
Also is all of the exhaust port plated or is it just the bore?
thankyou

 

[Aidix]

You could give it a try, just be carefull.

The pink ones are made of edelkorund (corundum in english). Very tough but fine surface and resistant to wear. It looks like a miniature pink sponge

Only the bore is plated, the ports are bare aluminium.

 

[stred-aerox]

cool thanks. Did a google search and corundum is also called aluminium oxide. That is great as i have lots of different ones of these. Is a polished funnel shape the best? Shall i also match the exhaust?
Thanks.

 

[Aidix]

Any shape is fine, as long as you can handle them....

As said before the only usefull thing you can do is porting, nothing else you can do with that dremel will give a noticable performance increase.

 

[stred-aerox]

what about increasing the size?
Can someone explain what the roof and things like that are?
Also how much bigger shall i make the exhaust port if any?
Thankyou..

 

[k0rgx]

Just don't make the exhaustport any wider, it's very wide out of the box. I know a guy who raised his exhaustport a bit on an Athena AC kit (don't know how much). With a C16 exhaust and a 21mm Amal/Arreche carb he got 13,x hp.
If i were you (and if you have a high reving exhaust), i would raise the exhaustport maybe a mm or a bit less and leave it at that.

 

[stred-aerox]

yes, i ended up raising the exhaust port about a mm any way. at the moment i have a 17.5 do and a technigas next, i was thinking of saving for the c16 but for me it is so expensive, wat other exhausts would work well like the metrakit?