RD400 carbs

[Skunk]

Who can ID all 5 of the connections on this carb?

287278

I THINK I know them, but I hope someone can confirm them. 4 are simple to pick.


If it ain't smokin' - it's broken.

[T.W.R]

1) air vent
2)fuel inlet
3)fuel feed to r/h carb
4) over flow
5) float bowl drain

[Skunk]

How sure are you? That's different to what I've been told. What you had as air vent I was told is the oil feed.
1 oil feed
2 fuel
3 feed to next carb
4 vent
5 overflow

Drain is a screw on the bottom of the bowl.

If it ain't smokin' - it's broken.

[Kickaha]

How sure are you? That's different to what I've been told. What you had as air vent I was told is the oil feed

1 = oil feed if it is the same as the LC

[T.W.R]

Yeah my bad...was looking at a diagram for a standard Mikuni VM carb

here's a parts listing diagram for RD400 carbs
http://rd400.no-ip.com/partlist/Carburetor.htm

[Skunk]

1 = oil feed if it is the same as the LC

That was my first mistake. The oil feed isn't visible in the photos and doesn't like anything like that...


If it ain't smokin' - it's broken.

[Skunk]

8 hours of research leads me to believe the following is correct:

1 air feed for float bowl
2 fuel inlet
3 fuel feed for choke to next carb
4 air feed to air jet
5 fuel overflow

Drain is a screw on the bottom of the bowl.


If it ain't smokin' - it's broken.

[Asher]

Hopefully this helps:

287311

287312

287313

Page 96 (http://www.scribd.com/doc/10925658/yamaha-rd250400-19651978-repair-manual)

[Skunk]

Hopefully this helps:

Page 96 (http://www.scribd.com/doc/10925658/yamaha-rd250400-19651978-repair-manual)

Mine is a different model. 2R9 stamped. Very similar though thanks.


If it ain't smokin' - it's broken.

[gammaguy]

mixing the feeds up would be a bad outcome

a parts manual would sort it and make sure it is the correct one for the model you have

[Skunk]

mixing the feeds up would be a bad outcome

a parts manual would sort it and make sure it is the correct one for the model you have

HaHa been there - done that!

I can't find a parts manual but I have a workshop manual that misses the important bits out. I've traced the internal galleries and read up on the RD and two stroke forums so I'm sure it's correct now. Unusual carb that is not even listed in the Suduco manual.


If it ain't smokin' - it's broken.

[RDjase]

Is #3 the air bleed/choke balance tube? or a separate fuel feed to other carb? and it only has one fuel line from the tank?

[Skunk]

Is #3 the air bleed/choke balance tube? or a separate fuel feed to other carb? and it only has one fuel line from the tank?

Fuel feed for the choke. I'll clarify that.


If it ain't smokin' - it's broken.

[RDjase]

Fuel feed for the choke. I'll clarify that.


If it ain't smokin' - it's broken.

I know a LC with a RZ engine doesn't run very well with the choke balance pipe still sitting on the bench......................:eek:

[Skunk]

I know a LC with a RZ engine doesn't run very well with the choke balance pipe still sitting on the bench......................:eek:

There is some debate as to whether it should have the balance pipe or not. I have one ready for the dyno.


If it ain't smokin' - it's broken.

[RDjase]

There is some debate as to whether it should have the balance pipe or not. I have one ready for the dyno.


If it ain't smokin' - it's broken.

As long as the ports are blocked off and the choke only works on one cylinder it shouldn't effect it, apart from starting maybe