piston mod

[Banshee Chad]

So my uncle is an old school snowmobile racer. During the holidays he told me about how they used to cut the skirt on the piston an eighth an inch on the intake side. He swears it made big gains.

 

Anyone hear of this or do this? If not how's it sound?

[bada450r]

it all depends on the builder and the kind of motor that your doing...drag, dune, mx, all builders do there own thing...skirts are cut to match cylinder sleeves, holes are drill....builders do all kinds of shit to the pistons,mostly to make them lighter and match porting style.

[uwenr]

So my uncle is an old school snowmobile racer. During the holidays he told me about how they used to cut the skirt on the piston an eighth an inch on the intake side. He swears it made big gains.

 

Anyone hear of this or do this? If not how's it sound?

I cut all my pistons, you can raise the intake window to match the intake of the cylinder.

[Banshee Chad]

So my bike is stock, no port at all. Would it help at all then or be usless.

[06specialedition]

hmmmmm...

[madjimmax]

I've never heard or doing that on the intake side but Vitos sells their super stock pistons which has the exhaust side notched out a pretty good bit. Most people would call that a poor mans port. I know for a fact that you can feel the difference between them and stock. A few of my buddies run them.

[Badasshee]

ive heard of boost ports on the piston. my builder brandon avery (wildcard racing) said they give u like 2 more hp across the board. give him a call hell set ya up!

[Banshee Chad]

Brandon is great, I'm out of town now, but need to talk to him when I get back about a few other things. Gonna get a tors kit and maybe an adjustable timing plate, and park brake block off, and maybe a tm designworks case saver. I'll bring up piston modding with him then. Those sound like good first mods?

[06specialedition]

Yeah Brandon (WILDCARD RACING) is very helpful and honest. He is doing my aggressive dune port and crank true&weld. Any of our site sponsors are good and honest people.

[Wildcardracing]

There is some power to be had by modifying the piston skirts, but I don't feel it's worth the reliability lost. I've seen dozens of broken pistons from enlarging the intake windows. I add a third window centered above the intake windows (boost port) on some of my builds to aid in crankcase filling, wristpin lubrication and crown cooling. It's placed higher in the meat of the piston so the piston looses less of its integrity than with window mods. What your uncle was likely refering to was trimming the skirts on the old piston port motors to change the intake timing rather than cutting the window/s of the jug. Your intake timing is controlled by your reed valves on a banshee engine.

-Brandon

[sleeper06]

Cutting the skirt on the intake side increases the duration of intake open period,unless you have a bg stroke or porting thaT calls for it you could hurt performance

[Banshee Chad]

Makes sense, he raced widowmaker well over 12 yrs ago with huge motors. Guess ill steer clear of the skirt modifications. Thanks guys, knew u guys would know what's up.