?'s about a MOD 670cc H.O. motor in polaris chassis

[arcticcatwill]

i am thinking about buying 1996 polaris RMK chassis w/ 144'' 2'' track, it has a bored and ported 670cc H.O. ski-doo motor in it, it also has crank shop twin pipes, comet clutch, with reworked 48mm carbs with pod filters. the motor needs rebuilding, i don't know if it needs only pistons or a whole top end (pistons, cylinders, head). and if it needs a whole top end, i would just set it back to stock, would the 48mm carbs still work with the stock boring? i dont know the current bore size yet. and the comet clutch needs rebuilt too, i don't realy know how much the clutch would cost yet. i don't know if the twin pipes are built for the stock 670 motor or the bore size. o and are 670cc and 670cc H.O. the same motor, could i use parts off eather motor?

please help, i don't realy know a lot about rotax motors, all i've ever herd was that there bomb proof

thanks, will

 

[arcticcatwill]

ttt anyone have any info

 

[winter brew]

If the cylinders and good, I would keep the big-bore. A 740 was a popular bore, pistons should be easy to find.
If you need to go back to 670, sell the 48's and get a set of 44's.....unless you ride real low altitude, you MAY get the 48's to work good as a 670.
If you need pistons or more info, I think Fastrax/Union Bay Racing can point you in the right direction, they did alot of 740's back in the day. There are also some people on here that know this engine well...BigJohn is one of them.