racer Posted February 21, 2005 Report Share Posted February 21, 2005 My Vito's SS forged pistons were a lot lighter then the stock cast pistons - I don't remember exactly how much but I weighed them on a digital scale and there was quite a difference. 327313[/snapback] probably so since the SS piston isnt a direct factory replacement. it has the exhaust edge tapered to give some cheated port work. if you weigh a wiseco 64mm, and a factory 64mm cast piston, the wiseco will weigh more. Quote Link to comment Share on other sites More sharing options...
theeechozen1 Posted February 21, 2005 Report Share Posted February 21, 2005 Pro-X pistons are about as close as it comes to a OEM Yama piston, I love em, forged pistons expand alot more than cast and can ware your bore out faster. Quote Link to comment Share on other sites More sharing options...
Tim C Posted February 21, 2005 Report Share Posted February 21, 2005 probably so since the SS piston isnt a direct factory replacement. it has the exhaust edge tapered to give some cheated port work. if you weigh a wiseco 64mm, and a factory 64mm cast piston, the wiseco will weigh more. 327321[/snapback] I can't see a Vito's piston being that much lighter then a Weisco piston - they are not cut that much Quote Link to comment Share on other sites More sharing options...
PRO1TUBER Posted February 21, 2005 Report Share Posted February 21, 2005 ART makes the oem yamaha pistons & pro-X is a better piston than stock & is also the only piston & rings that are universal w/ the OEM's .......as far as the best pistons ... i would only run WIESCO...just did a rebuild & what did i use?? WIESCO the lightest & durable... on one of my motors i used ART (the OEM) & the where breaking apart!! literally !!! pieces of the pistons where breaking & bouncing around in the combustion chamber & fucked up my domes & lost compresion...bc they broke apart inbetween the 2 rings......only run wiesco.... try other then try wiesco .. u will never go back!!!! there is my $00.02 Quote Link to comment Share on other sites More sharing options...
duecebanshees Posted February 21, 2005 Report Share Posted February 21, 2005 When my cylinders came back from Duncan Racing aka Paul Turner national port work. They sent them to me freshly bored with pro-x pistons. I had always ran wiseco until then. And at that point had no choice unless I wanted to get them bored again. So to make a long story short. I was checking compression one day after a weekend of riding and noticed one side had dropped compression a little. I tore it down to find both pistons were CRACKED on the intake sides. And about to explode in my engine. When I had the cylinders bored I went back with WISECO. And will use nothing else. I have not had a wiseco break or crack before like the cast pro-x. I can tell you the same thing happened to a buddies 250r. Of course this is just my personal experience and obviously just my opionion. Good luck with what ever you decide to go with. Quote Link to comment Share on other sites More sharing options...
duner Posted February 21, 2005 Report Share Posted February 21, 2005 (edited) My Vito's SS forged pistons were a lot lighter then the stock cast pistons - I don't remember exactly how much but I weighed them on a digital scale and there was quite a difference. 327313[/snapback] Agreed,I have NEVER seen a cast piston lighter than a forged. Edited February 21, 2005 by duner Quote Link to comment Share on other sites More sharing options...
racer Posted February 21, 2005 Report Share Posted February 21, 2005 Agreed,I have NEVER seen a cast piston lighter than a forged. 327351[/snapback] hmm, maybe im wrong. but it seems i read somewhere that the casting prcoess makes them heavier. we need a resident metalurgist to answeer these questions. Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted February 21, 2005 Report Share Posted February 21, 2005 my brothers stock 04 pistons broke apart between the rings and it locked up. they just basically started falling apart. those things are junk. the banshee he had before his 04 we put pro junk in during a rebuild and it wasnt long before the compression was way down. i dont know what weighs more or weighs less but ill never use anything other than wiseco. Quote Link to comment Share on other sites More sharing options...
2stroke_addict Posted February 21, 2005 Report Share Posted February 21, 2005 i use vito's SS forged, they work awesome, no problems i'd recommend you getting those, expensive?? maybe but once you try them you'll know where did the extra money go. Quote Link to comment Share on other sites More sharing options...
Nightrider Posted February 22, 2005 Author Report Share Posted February 22, 2005 I ran forged in my dirt bikes for years,they always wore the sleeves out before the piston.Needed to overbore every time I rebuilt the top-end.Sure,I could have just honed it,but it would have clanked around in the cylinder until it warmed up. My 01' has approx 110 hrs on original pistons and rings the comp was still good 130-135(milled head).It was originally 145 when I first put the head on,so in 3 years I only lost 10 psi,no too shabby if you ask me. The bores were less than .0005 out of round.I've had Wiseco's with 50 hrs and the bores were .001-.0015 egg shaped already. I argued the cast vs forged piston for years,but I've come to realize the new cast will perform just as good,if not "better" than forged up to certain applications. As far as longevity,i can honestly say that the original oem piston is one durable mofo.After 110 hrs of hard trail abuse with yamalube 2R,they are right under the low spec for piston replacement.No hotspots or blow by on the pistons,no score marks in the bores. I was just looking for an alternative to stock.Wisecos will always be my last resort and for 33 dollars a piston w/bearing&pin.(Employee discount thru friend)its hard not to go with them,but I'll pass. Quote Link to comment Share on other sites More sharing options...
RNBRAD Posted February 22, 2005 Report Share Posted February 22, 2005 Pro-X pistons are about as close as it comes to a OEM Yama piston, I love em, forged pistons expand alot more than cast and can ware your bore out faster. 327322[/snapback] Word!!! I've used pro-x for several years and never a hint of a problem. There is definite benefits to using cast pistons. Though I would never recommend using cast pistons with higher compression unless you plan on running race gas. Plenty of people ruin cast pistons from improper tuning and detonation and a forged piston will buy you more time before the pistons goes. You need tighter tolerances with cast and a lot of people don't follow those. So they are more finicky or however you spell it as far as a piston is concerned but an excellent piston no doubt. Here's a link you may have read Cole about the weight issues. I don't know when this was written or how much holds true for banshee pistons. So take it as you wish. It wasn't a deciding factor for me. I've just had better luck with pro-x than wiseco's. But I think anyone can probably get a bad piston. I wouldn't hesitate using wiseco's again and I may in the future. Cast v/s forged pistons Quote Link to comment Share on other sites More sharing options...
MotulMonsta Posted February 22, 2005 Report Share Posted February 22, 2005 Cast pistons have more irregularities like larger pores, voids from the casting process. This equels to a weaker piston that will fail from fatigue when compared to a forged piston. Forging a piston means that a set of dies are pressed together forcing the metal under an extreme pressure to take the shape of the dies. The metal's denisty is higher which results in a longer warm up period but it is stronger. Forged pistons can be made lighter then a cast piston as material can be removed from non critical areas like the skirt and underside of the dome. Cast pistons are prone to cold seizures as the piston will expand faster then the cylinders, but they also have a shorter warm up period. Forged pistons take longer to warm up and the potential for cylinder damage is greater as the skirt slaps around until it is warm. Forged pistons are high performace where engine reliability is paramount. You'll blow up a cast piston long before you'll blow up a forged. Quote Link to comment Share on other sites More sharing options...
RNBRAD Posted February 22, 2005 Report Share Posted February 22, 2005 MM forged pistons are more prone to cold seizure. You have to let them warm up first, you will heat the pistons up faster than you do the juggs and walla. Definitely more critcal with forged. Cast you can fire up and go. Also read that link in my last post at the bottom, you have some stuff turned around. Quote Link to comment Share on other sites More sharing options...
Blacksmith Posted February 22, 2005 Report Share Posted February 22, 2005 To do what I can to answer the original question, I tried to run a set of the WSM pistons. I had them in for about 2 weeks when one of the snap rings that they use as a circlip came out and cut a grove in the cylinder. Sent my jugs and the old pistons to WSM and they cut my 10 over cylinders out to 40 over and sent me a new set of their top of the line pistons. When I put a mic to what they had done, they had almost .008 clearance with their bore job. I had to hone the cylinders out some more and go to 50 over pistons just to use the cylinders. Long story short, I have a set of 40 over WSM pistons - anyone interested? Quote Link to comment Share on other sites More sharing options...
racer Posted February 22, 2005 Report Share Posted February 22, 2005 MotulMonsta summed up everything i had thought to be right about pistin design. However after reading Brad's article I guess were both wrong in some ways. Itd would be nice if a wiseco rep visited this site once in a while but that doesnt appear to be happening. So then, I guess the best way to get good light pistons is to have a set of wisecos custom cut and balanced for your particular needs. Quote Link to comment Share on other sites More sharing options...
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