Project playing problem

[Priliars125]

Hi all been hearing good things bout this site well I have an rs125 I'm v.good but I've just acquired a cheap sr50 new shape carb 54 plate it starts and idles also revs clean but when it's under load at anymore than 3/4 throttle it completely bogs does not even stutter jus goes buuuuurrrrrr and if I keep open wwould eventually die completely so wtf as its under load only I have no clue

Any help appreciated guys

[Snugg]

Welcome to the forum.

What jets are in the carb? Stock carb I'm assuming

[Daniel-S]

Sounds like the main jet is too big

[Snugg]

Sounds like the main jet is too big

I would agree

[Daniel-S]

Main jet kicks in between 3/4 and full throttle, 1/2-3/4 throttle is majority controlled by the needle position(air) and needle jet(fuel)... Find what position specifically it happens at and we should be able to help you.

[Snugg]

Daniel, is the "needle jet" and Pilot jet the same thing?

[Daniel-S]

Simply yep... Main and pilot/needle jet, Pilot jet is more for fine tuning to specific points where the needle is clipped.

With bogging at 1/2-3/4 throttle it could be that there isn't enough air coming through so you have to adjust the needle position to allow more air Or you could drop the pilot jet down... Or is could be that there is too much fuel coming through in whick case you could either drop the pilot jet down or take the needle up/down(Not 100% sure which way) a notch.

Bogging after 3/4 throttle is 100% too much fuel through main jet meaning you would drop the main jet down OR adjust the needle to allow more air.

You just have to be careful as too much adjustment will completely take out other things, Eg main jet.