2 stroke carb

[Caseys 300ex]

I was in a dirtwheels reading and i noticed that esr was selling 2 stroke carbs. Can you use a 250r carb on a 300ex? IS there a difference between a 2 stroke and a 4 stroke carb? The reason for me asking is because the carbs were dirt cheap and i might get one.

[firefighterjosh]

Good question. We put a Husquvarna (sp?) 125 carb on a 4-stroke go cart so I think it is possible, but I don't think a 250r carb would work with a 300ex. I may be wrong though.

[Project300EX]

I'd like a little info on this too. I've been looking and trying to decide what carb to get for my RM250 project motor.

[joshyz125]

the 2 stroke carbs don't have accelerator pumps, so they are going to have a pretty hard stumble when you stab the throttle

[86 Quad R]

i'm no expert on this by no means but, from observation and a lil experience. the smaller 4 stroke engines dont really require a carb with the eccelerator pump on them. i/e the ole honda trx 125, 200, 250 and even the older 300. all of which operated on the smaller bore carb's that had faster air flow over/across the circuits.

i'm of the opinion that after the bore (carb) reaches a particular/larger size(as does in the larger engines) the air speed decreases and therefor requires an accelerator pump for the lower rpm's to prevent the BOG.

i'f you notice that the carbs on the smaller 4 strokes that dont have the accelerator pumps are made a lil differently than the 2 stroke carbs. meaning, the 2 stroke carbs have the lil air damn located right in front of the orfic where the slide needle slides up n down. the 4 stroke carbs do not.

[Caseys 300ex]

Thanks for the help. I think ill just buy a 400ex carb because i dont want to risk buy a new 2 stroke carb and then it be a pile of crap.

[bwamos]

You're just basically missing the accelerator pump on the 2-stroke carbs.

The 300ex definatly needs one.

I had an old Mikuni Flatslide carb for my 300ex that didn't have an accelerator pump. It would definatly bog down when you hit the throttle hard when riding. It would take off like a bat outa heck afterward.. but it was definatly needing an accelrator pump. It is sitting in my storage cabinet.. lol.

[Caseys 300ex]

Ya so the 400ex had the accelerator pump right? I have and exhaust and a k&n filter without and airbox lid so could i have a stock 400ex carb with the stock jets or do i need to rejet the 400ex carb.

[86 Quad R]

if you've changed the filter, air box configuration and exhaust you'll deffinately need to change the carbs jetting on the stock carb.

[Caseys 300ex]

ok thanks

[bwamos]

Actually with a 300ex. Pipe/filter/no lid the 400ex stock jetting on the carb will be a good starting point. You will probably have to go up or down a jet or 2 though.