stock sx stomping all over my 650sj?!?

[Kwit]

Everyone told me that a stock 650sj woud be faster and snappier then a stock kawi 650sx. I owned a 650sx with a few bolt ons and it was conciderably faster then my stock 650sj ...which I expected. All my 650sj has is a carbon kevlar ride plate with a d cut and a tdr waterbox on 40:1 with 89 octane. my buddies ski has a all stock sx with a westcoast pipe on 50:1... i know i said stock but a pipe cant make all that difference. i mean i rode this thing and it was almost difficult to ride it mine was so much slower. Im not taking top speed. More or less over all perfromance. my ski has good even compression and runs mint... is there something wrong with it? if feels so underpowerd compard to kawi sx's that ive rode.. stock and modded. the motor on my ski runs nice and cool aswell. what can i do to make this thing faster like everyone said it should be? shoud i run 50:1 octane? let me know eh.

 

[Boris]

If the pipe doesn't make that much of a difference than why not pick up a $200 Caufman or Pro-Tec.

 

[Gainera2582]

Stock yamaha exhausts are very restrictive and limit engine performance. Adding any aftermarket exhaust(and the proper jets for your carb) will give you and immediate performance gain on your setup.

 

[SUPERJET-113]

The 650 6M6 cylinder has the most conservative porting in the history of PWC cylinders! Put a 701 61X cylinder(or better yet port it) on it with a pipe and it will rip!

 

[romack991]

have you looked at your prop? a damage to the blades will loose a lot of power.

 

[Freestylin-FX1]

thats odd my modded 650sx will almost keep up with my stock square

 

[Kwit]

prop is brand new looking. Anyone know where I can send my cylinder to get ported? Anyone on here do good port jobs? howmuch does porting usually cost for a nice mild port? also I have a stock sj pump/w solas prop here I will trade with some cash for a pipe for my setup if someone has one laying around. let me know whatchas got:

need:

-a pipe
-maybe a slighly higher compression head or have mine milled a little
-port work
-top loader scoop grate
-low pitch prop or have mine repitched... I have 2 solas props to trade for a 15 or sumthing with a lot of lowend
- pump cone

let me know what you guys got this is all for my 91 sn 650 superjet

i have lots of stock sn parts inluding electrical box and a pump in codcondition. Aswell at a good 650sx bottom end let me know whatcha got email me at kwit21@aol.com

 

[jeepmark4x4]

instead of port work to your 6m6 you should buy a 61x...but...I rode a buddies 650 SJ every now and than for a year or so and it had a pro-tec pipe/carbon reeds/9-12 prop (i think)/high compression head and that thing was solid! It had more pop than my other friends 650sx that has the same mods.

I have aftermarket parts for a 6m6: If interested just PM me

Brand new carbon reeds with less than an hour on them
2 piece high compression head giving 195 psi
UMI straight bars

 

[Waste Land]

Pipes make a TON of diffrence!! All through the powerband

Stock yamaha exhausts are very restrictive and limit engine performance. Adding any aftermarket exhaust(and the proper jets for your carb) will give you and immediate performance gain on your setup.

It's not so much the restrictivness of the stocker as it is the design. It's more of a muffler then a tuned pipe. Ofcourse it does what it needs to but its the design of an aftermarket pipe and chamber that brings the power.

http://auto.howstuffworks.com/question636.htm

 

[BombThreat]

Hey man this is what id do if you didnt want to go 701.

cut the head
get a cheap 650 pipe
9/17 prop (which i have if you need one)
reeds (ive got some boysens)
top loader intake grate