10 w carb

[jollyr6]

Hi all in my 125 lc Haynes Manueline it says the 12 a and the 10w carbs except for the main air jet are the Venturi sizes the same?? And are the float bowls the same size there must be someone who knows info would be much appreciated. Jolly

[neil]

the venturi and float bowls are the same

[jollyr6]

Thanks for that Neil so it's just the main air jet then wonder if I can convert mine

[mellow]

the internal drillings may be different

[neil]

if you look on the right hand side of the 12a theres a plastic elbow which the 10w doesnt have. in the mouth of the intake there is a little plug over the air jet hole, the needle jet is also different on the 10w. my 125 has been ported and runs with a micron, i have tried 12a and 10w and noticed no difference.

[Tone]

I've got a Yamaha service data book that says:

RD125LC (12A)

Main Jet #195
Jet Needle-Clip Position 5GN36-4
Needle Jet 0.2
Cutaway 1.5
Pilot Jet #20
Air Screw (Turns out ) 1 and 1/2
Float Height 21mm

RD125LC (10W)

Main Jet #155
Jet Needle-Clip Position 5GN36-3
Needle Jet 0.8
Cutaway 1.5
Pilot Jet #20
Air Screw (Turns Out) 1 and 1/2
Float Height 21mm

[looey]

Well I know the 10W is the carb on the unrestricted bike but I see no difference in performance whatever carb I fit to my Mk1 10W bike.

I have several 10W carbs, an 11Y (tried that with and without 10W internals) and a couple 12A, and as long as they are jetted correctly for the pipe/filter combination the bikes goes exactly the same....... well not that I can notice any difference and it will do the same top speed with any carb

[jollyr6]

thanks for all the info guys so what your saying is i dont need to bother faffing with my 12a carb bike should be as fast as an 10w that right

[looey]

That's my experience, even back in 1984 I had a brand 12A bike and with an Allpeed fitted and the needle raised one clip it was as fast as any 10w bike.