SX/SXi/SXi Pro Whats the dirrerence between pistons for the 750

[50embarr]

So I have 3 750sx and I know someday one of the top ends is going to go and I wanna get a stock 80mm top end rebuild kit and is wondering what the difference between the wiseco kits for $340 or the cheap ones on amazon for $220 is it the material used in the pistons or just the brand name. Is all aftermarket pistons for the 750sx all flat or is there someone that makes a piston that will perform better at the stock 80mm bore. I'm currently running a stock head but have a extra one I want to send off to get milled to 180ish which I would use when I do the top end rebuild. What have u guys used in the past?

 

[jetman624]

I like Pro-X pistons myself.

 

[vomitspot]

not all pistons are the same
there is cast and forged
not all 750 pistons are the same
there is big pin and small pin

when you say i have a 750 sx i think all sx have small pin
thats the size of the wrist pin that holds the piston to the rod
small pin 20 mm
big pin 22 mm
i think all kawie pistons are flat tops
jason

 

[50embarr]

not all pistons are the same
there is cast and forged
not all 750 pistons are the same
there is big pin and small pin

when you say i have a 750 sx i think all sx have small pin
thats the size of the wrist pin that holds the piston to the rod
small pin 20 mm
big pin 22 mm
i think all kawie pistons are flat tops
jason

Ya I forgot to mention it is a small pin but which do experienced riders use more cast or forged? Is one better for high compression, sorry for asking so many questions I just wanna be sure when I rebuild my top end I get the best bang for my buck oh ya I forgot I did figure out that stock bore pistons are 80mm, but how much more can you punch it out before you have to sleve the block/ jug?

 

[Coldwater]

If I remember correctly I think 83mm is the absolute farthest you can bore the stock sleeves in a 750 but that is the sxi (big pin) cylinders, might be less for the small pin. Group K has some fairly clear write ups on this on their site you might be intrested in reading. I would talk to whoever you are going to have over bore them before hand for their recommedations as well.

 

[Coldwater]

Sorry just reread your post and realized you have a small pin, I think the cylinder for the 750's stayed the same except for the port timing between the big and small pin but again I would make sure you talk to reputable builder.

 

[garrcass]

Cold watter is right 83mm is about as big as they can get that's right at 83. He is also right about the porting..

Slugs are slugs get some ProX and call it a day.. if you want to save some money WSM platnums will work the coating on them will save the bore sometimes if they try and stick on you. Get some fresh wristpin bearings when you get your pistons.

http://www.jet-world.net/partsacc/pkitsprox.asp