300ex carb on a 250sx

[OldSchoolin86]

The topic came up when I suggested looking into doing this in another thread. The carbs look pretty close and I'm wondering how hard this may be. More importanly, will it help?

Q#1
What size is the 250sx carb?

Q#2
What size is the 300ex carb?

Q#3
Will a trike like the SX benifit from an accelerator pump?

There's more Q's then that but it's a start. I'm checking but I think the 300ex carb is a 32mm.

[conig]

31 mm 350x accourding to this site., but the carb fits in the stock boot, so the bell at the fron't may be the only thing larger.

300ex Carburetion 32mm piston-valve with accelerator pump

250es has a 22mm carb and I remeber reading that 22 or 28mm was used for the big red but could not find anything to substantiate it. Hopefully some one with a service manual can tell us something here.

the question is weither or not the slide is bigger on the 350x or not. some of the larger keighn and mikuni carbs have the same body and slide and have larger bells or air horns.

350x on 250sx
http://3wheelerworldforums.com/showthread.php?t=20416

http://3wheelerworldforums.com/showthread.php?t=2792

http://www.3wheelerworldforums.com/showthread.php?t=20104&highlight=250x+carb

http://www.3wheelerworldforums.com/showthread.php?t=24682&highlight=300ex

theres some info in the above links.

[Tri-ZNate]

the sx is 27 so the big red should be about the same size.

Awesome according to some of the guys I can just take my SX jets and put them in the 350x carb

[conig]

ok so 350x slide is 4 mm larger, but the external carb dimensions are pretty similiar, suposedly the 300es accelerator pump makes cold starting easier. Thats not as huge a problem down here in the south.

[OldSchoolin86]

Ok cool, I see some searching could have yielded some good info but this is good. I'm shocked that the 350x carb is smaller then the 250x/300ex carb. If I had a 350x I'd be tossing the 31mm and installing the 32mm with the accelerator pump. The accelerator pump can help on start up but it's mainly there to help out when you pin the throttle, it gives it a little more go. As for the SX 27mm to 31mm is a heathly jump but not near as much as I thought. IDK why, but I thought the 350x had a 34mm.

[conig]

whats weird is how many times I searched this website for the info I just posted. I start searching the same things on google and I get 3wheelerworld.com posts Ive never seen before.....Gottas love google.

Im still thinking 300ex carb not becuase its bigger but they are cheaper and more plentiful, Id hate to rig something up on my red resto mod that someone else coyuld use for a 100% OEM resto. ya know?

[OldSchoolin86]

whats weird is how many times I searched this website for the info I just posted. I start searching the same things on google and I get 3wheelerworld.com posts Ive never seen before.....Gottas love google.

Im still thinking 300ex carb not becuase its bigger but they are cheaper and more plentiful, Id hate to rig something up on my red resto mod that someone else coyuld use for a 100% OEM resto. ya know?
Great point!!! I'd think that accel pump would be nice too.