XJ 750 carbs on a XJ 650

What happens when you put XJ 750 carbs on a XJ 650, does it run rich or lean, loss of power if any? Thanks grm

 

as long as they're the same brand- hitachi or mikuni- I cant remember if this is how it goes, but the 550 uses one brand and the 650's and 750's use the same brand, only difference is the two jets in the bottom of the bowl

I DONT ave a 650 and a 750, i have a 750 and 700- and they're the same

 

if you put the 750 carbs on the 650 will run a bit rich and visa versa the 25 cc difference per piston shouldnt make much difference probbibly wont need choke when starting cold if you have a k&n and 4 into 1 would probbibly be perfect but will probbibly run just fine the way they are as long as they fit

 

Ok, I plan to take to Mexico when I move the Alt is around 5000 ft so would that make it run rich or lean? BTW the are both the same carbs just different jets.

 

the higher you go the leaner it gets air wise

 

Umm, not so sure on that.......!

The higher the altitude, the thinner the air (less dense), thus the richer the mixture becomes for the same size fuel jets.

This is why you decrease fuel jet sizes for higher altitudes....otherwise, the bike runs rich (too much fuel for a lesser amount of air).


Besides the size of the fuel and air jets, the main jet needles are diffrent between the XJ650 and XJ750 Hitachi carbs.


Although the following information is in specific reference to carb tuning when using pod air filters, the same guidelines probably are close enough for stock systems, too:

- Decrease main fuel jet size by 2 sizes per every 2000' above sea level.

- Decrease pilot fuel jet size by 1 for every 6000' above sea level.

 

that's a bold statement- I dont know if you can tune out the difference in jet sizes, nor would i recommend throwing on pods as a solution-- because 750's run 120/40 setup if i remember correctly.. which is qute a bit lower than people have reported with their pods