shawn941 Posted July 22, 2010 Report Share Posted July 22, 2010 ok,,,i melted a piston 2 weeks ago and bought some stock non ported cylinders with a new bore job and a new pair of vitos super stock pistons. im just curious how many jet sizes i should go up on the mains. the previous cylinders were also non ported as well. i have a weird combination as far as the carbs go. im running a really rich needle with 60 pilots and 128 mains,,,weird, i know. apparently alot of dirt bike guys run set ups like this. they are 28mm pwks and actually had 125 mains in it before i put in ported reed cages,,,it leaned out a little bit so i went to 128's.and no, the piston did not melt because of this jetting combo either, i did several plug chops to ensure it was jetted correctly and ran this set up for 2 years. the reason the piston melted was because i didnt run my usual half 110 octane,my fault totally. its a stock head shaved .050 and rechambered to 18-19cc and i thought was border line race fuel,i ran straight 93 for 30 minutes and shee melted. any help would be appreciated. Quote Link to comment Share on other sites More sharing options...
banshee67 Posted July 27, 2010 Report Share Posted July 27, 2010 now what are you exactly asking? Quote Link to comment Share on other sites More sharing options...
shawn941 Posted July 27, 2010 Author Report Share Posted July 27, 2010 now what are you exactly asking? how many jet sizes to go up with these super stock pistons. i went up a couple sizes, plug chop this weekend. seems to run great! Quote Link to comment Share on other sites More sharing options...
banshee67 Posted July 27, 2010 Report Share Posted July 27, 2010 they way my family and i jet our shees is we get it in the ball park just by idle. then we take them out for a few minutes of ripping on it really hard and depending on how rich or lean it is depends on where the next jet size is. i would start a little richer than what you think and go from there. with how your wierd setup is i would start with a 150 or so. and see how it idles Quote Link to comment Share on other sites More sharing options...
shawn941 Posted July 27, 2010 Author Report Share Posted July 27, 2010 they way my family and i jet our shees is we get it in the ball park just by idle. then we take them out for a few minutes of ripping on it really hard and depending on how rich or lean it is depends on where the next jet size is. i would start a little richer than what you think and go from there. with how your wierd setup is i would start with a 150 or so. and see how it idles im not sure you quite understand the question. the bike was jetted perfect before i rebuilt the top end. i just heard from someone that the vitos super stock pistons may require a bit richer jetting. i put the stock cages back in after the rebuild which richened it up by 3 jet sizes. its almost spot on right now so problem solved! thanx for your input.... Quote Link to comment Share on other sites More sharing options...
banshee67 Posted July 27, 2010 Report Share Posted July 27, 2010 ok your welcome i think. i was really sure what you were asking in the first place but i think i understand now haha. nut as long as it runs like you want then ok. good luck Quote Link to comment Share on other sites More sharing options...
rdzbangshee Posted August 25, 2010 Report Share Posted August 25, 2010 ok,,,i melted a piston 2 weeks ago and bought some stock non ported cylinders with a new bore job and a new pair of vitos super stock pistons. im just curious how many jet sizes i should go up on the mains. the previous cylinders were also non ported as well. i have a weird combination as far as the carbs go. im running a really rich needle with 60 pilots and 128 mains,,,weird, i know. apparently alot of dirt bike guys run set ups like this. they are 28mm pwks and actually had 125 mains in it before i put in ported reed cages,,,it leaned out a little bit so i went to 128's.and no, the piston did not melt because of this jetting combo either, i did several plug chops to ensure it was jetted correctly and ran this set up for 2 years. the reason the piston melted was because i didnt run my usual half 110 octane,my fault totally. its a stock head shaved .050 and rechambered to 18-19cc and i thought was border line race fuel,i ran straight 93 for 30 minutes and shee melted. any help would be appreciated. 100% stock engine with super stock piston will run to hot and loose compression you have to raise the intake ports and exaust 4mm and run 35 pilot vito needle and 340 main. +4 timing aftermarket pipes Quote Link to comment Share on other sites More sharing options...
madjimmax Posted August 25, 2010 Report Share Posted August 25, 2010 100% stock engine with super stock piston will run to hot and loose compression you have to raise the intake ports and exaust 4mm and run 35 pilot vito needle and 340 main. +4 timing aftermarket pipes Fist thing is these pistons will run fine in a stock engine and it sounds your talking about stock carbs while to OP is talking 28pwks. And just for your info a 35 pilot in stockers are way too big stock carbs with aftermarket pipes require a 27.5 pilot and thats pretty much all aftermarket pipes. All the vitos pistons do is change the exhaust timing a little. I've ran them in my shee once and both of my sons run them in their blasters with no added heat. If you've ran them and overheated its because you wasnt jetted properly. Quote Link to comment Share on other sites More sharing options...
prssantana Posted August 26, 2010 Report Share Posted August 26, 2010 Fist thing is these pistons will run fine in a stock engine and it sounds your talking about stock carbs while to OP is talking 28pwks. And just for your info a 35 pilot in stockers are way too big stock carbs with aftermarket pipes require a 27.5 pilot and thats pretty much all aftermarket pipes. All the vitos pistons do is change the exhaust timing a little. I've ran them in my shee once and both of my sons run them in their blasters with no added heat. If you've ran them and overheated its because you wasnt jetted properly. When you used them did you notice a difference in power? I just put some in mine and havent had the chance to really ride it. I was wondering the same thing as the op because the site just says to buy their jet kit. I ended up just going to 270 to 280 on stock carbs. The guy that did my machine work said they might even be fine at 270 to just try it and see. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.