650 and 300sx father son project help (newbie)

[REKLES]

Hello all,
like the title says, i wanted to start a new project with my son this winter when we are not dirt bike riding. I am completely new to jet skis, and read alot more than i post.
My goal is to have the 300sx be able to hang with my 650sx Eventually with my 60lbs son on it. problem i cannot find any hop up parts or vary little info on the 300sx.

Oh yeah this is a budget build too so im not trying to go broke getting these skis going and hopefully fast.

both the 650 and the 300 need new top ends so i plan to take both engines out and make them run on premix. the 650 is missing the exhaust and the electronics.
I am in this project for $150 and im looking to spend $600 into the engines alone. I know right off the bat im gonna get a westcoast head for the 650 and exhaust to but what other tips and tricks should i do to the engine? also the 300 is basically a 650 less a cylinder so most of the stuff i do to the 650 should work the same for the 300 right?

any help on how i should approach this would be greatly appreciated

THANKS

[REKLES]

cool thanks

[kaw650sx1993]

The 650 and 300 is a little difrrent if you look at the hulls, i dont know how much similar underneath them are though. The js300 and sx300 are very similar. i would bore the the 300, mill the head, maybe 38/44 SBN carb,flame arrestor and get a exhaust off ebay for it for $250. The 300's are the easiest engine ever, i love them ther so easy to work on and everything.

[The Greygoose]

Welcome !

[WB1994]

Find a running 650 for $250-300 ish and slap it in the 300 SX.

Welcome.