SandDragIt Posted April 18, 2011 Report Share Posted April 18, 2011 So i just pulled my buddies ported bike apart to put a new topend in it but noticed the piston windows have been opened up? should I take a dremel and open up the new ones? check out the pic..the piston I removed is on the right side..new piston on the left. Quote Link to comment Share on other sites More sharing options...
bigblockbanshee Posted April 18, 2011 Report Share Posted April 18, 2011 Has it indeed been cut or was it cast that way? Looks like a Vito's Superstock piston to me. Supposed to "fool" the engine into thinking it's ported or something. That's the terminology that others have used anyway. Quote Link to comment Share on other sites More sharing options...
SandDragIt Posted April 18, 2011 Author Report Share Posted April 18, 2011 It's definitely been cut..its not a clean job either..looks like someone did it themselves..they are wiseco pistons. its got nice portwork done but it didn't run like i felt it should. Maybe the previous owner hacked on the piston thinking he was doing something? Quote Link to comment Share on other sites More sharing options...
DallasGDub Posted April 18, 2011 Report Share Posted April 18, 2011 I remember a builder around Washington state that did that to match ported stock cylinders. Jokers Racing or something like that. I was told by other builders it was not a good idea. Quote Link to comment Share on other sites More sharing options...
SandDragIt Posted April 18, 2011 Author Report Share Posted April 18, 2011 i think im gonna throw these new pistons in it and see how it runs. I don't think its a good idea Quote Link to comment Share on other sites More sharing options...
BB3 Posted April 18, 2011 Report Share Posted April 18, 2011 Ive made the holes wider on some of my motors but never cut into the middle of them only the out sides. I also used a mill to cut them and stoned them down to make sure it couldnt get any kind of cracks off the cuts. Quote Link to comment Share on other sites More sharing options...
SandDragIt Posted April 18, 2011 Author Report Share Posted April 18, 2011 Ive made the holes wider on some of my motors but never cut into the middle of them only the out sides. I also used a mill to cut them and stoned them down to make sure it couldnt get any kind of cracks off the cuts. I could see how that might help. The piston windows are only cut on the top on these..they are taller by about a 1/4 inch or so..I've never touched any of the pistons in my drag ported stock cyl bike. Quote Link to comment Share on other sites More sharing options...
WINDYCITYJOHN400 Posted April 18, 2011 Report Share Posted April 18, 2011 Has it indeed been cut or was it cast that way? Looks like a Vito's Superstock piston to me. Supposed to "fool" the engine into thinking it's ported or something. That's the terminology that others have used anyway. The Vito's Super Stock pistons have a lowerd top on the exhaust side. It drops the top edge of the piston closer to the top ring. (They have lowered the rings so it's not a big deal) The edge matches the exhaust port. The piston top edge is down 1.5mm. So when you use them, the motor acts as if you have raised the exhaust port 1.5mm. That is the same as many port jobs. It works great. But it doesn't have a window mod like this piston. Quote Link to comment Share on other sites More sharing options...
bigblockbanshee Posted April 18, 2011 Report Share Posted April 18, 2011 Ah ok, for some reason I thought the intake windows were modified too. Pay no mind to me, carry on... Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted April 18, 2011 Report Share Posted April 18, 2011 I would put them in as they came and not raise the windows. I believe you are exactly right when you said someone thought they were doing something. Quote Link to comment Share on other sites More sharing options...
camatv Posted April 18, 2011 Report Share Posted April 18, 2011 some certain engines dont even have the windows. hehehe i used to do holes or port match the windows. then i noticed it really didnt do much but make the pistons lighter on that side and sometimes cause cracks ( after a long run time) so i quit doing it. whats funny is the less i do to them now the better them seem to run.. Quote Link to comment Share on other sites More sharing options...
RollinRhino Posted April 19, 2011 Report Share Posted April 19, 2011 WSM F1s have enlarged windows too. They are shaped differently than these in the picture. Quote Link to comment Share on other sites More sharing options...
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