SX/SXi/SXi Pro how to tune dual carbs.

[kass727]

hey recently i bought a set of dual carbs for my 92 750 sx but im hesitent to install them im not really sure how to tune them to be exact to each other. how can i tell if one is giveing two much fuel or to little. also im not quite sure if each carb will feed only one cylinder or if it all mixes together in the crank case anyway. please anyone with some pointers and tips would be a great help.

 

[madscientist]

what mods have you done to the ski? what carbs are you wanting to put on?

it takes twice as long to tune as duals, but can be worth it.

 

[KAWI4ME4NOW]

more like if your ski is a 92 most likely its a small pin rite??

 

[kass727]

yea its a 92 small pin only mods done are, a coffman rocket pipe, wiesco forgred piston, boysen reeds. other than that has stock bore, oil pump block off, and primer kit. the carbs are off a 96 sxi i beleive and are 38mm keihins, with 44mm intake bore. both have had choke removed. also does anyone have pics or a diagram of how to run the fuel and return lines for the dual setup.

 

[madscientist]

check your jets. on my dual set i am running 75 low, 48 mid(stock), and 125 mains with a blaster limited pipe, ported exhaust, h/c head @ 185psi, 650 electircs, advanced t0 27*.

about 3/4 turn out on the bottom and 1/2 out on the top.

 

[kass727]

do you happen to have a pic or something to show how you run the fuel lines with the dual set up.

 

[madscientist]

lower fitting is the in from the tank, the upper is the return line , run the in from the tank to the lower on the carb with the fuel pump attached, the return from this carb (upper) will go to the lower on the slave carb, the return (upper) will go to the tanks return fitting.

 

[kass727]

thats what i thought but im confused tho bc both of my carbs have fuel pumps on them. do i need to block off the pump on the slave carb or nehting or can i just leave it as is and only use the one pump. or do i put a y valve and hook up both pumps.

 

[SterlingSilva]

perhaps it would be best if you posted up a couple pics.

 

[madscientist]

just use a y on both the return and supply lines

 

[kass727]

so i can set them up basicaly as two individual carbs, and just spilt each line with a y?

 

[madscientist]

yes, and to tune you will do plug checks and adjust individually

 

[kass727]

thanks alot. ill give it a shot tonight.