ID RD carbs

[Skunk]

I think I know which are which but are there any expert eyes to check?
Top: RD350
Middle: RD400
Bottom: RD350LC (maybe 250LC?)

Am I even close?

[pete-blen]

I had all 3 bikes... but I never payed that closer attention to what the carbs looked like..
but I can tell yer
RD350B had #132 main jets..Last of the RD350 before the RD400C
RD350LC had #220 main jets..
Could help ID the carbs...

there were 3 versions of the RD400... C/D were the same.. E model in 78 was basicly a hot C/D ..Had a little plastic tail unit on
the rear of the seat with a all matt black engine..
Then the F/G.. had the one peice head with the ram air cooling...
So what I'm saying there maybe 3 diffrent carbs for the RD400 range...

[Skunk]

I had all 3 bikes... but I never payed that closer attention to what the carbs looked like..
but I can tell yer
RD350B had #132 main jets..Last of the RD350 before the RD400C
RD350LC had #220 main jets..
Could help ID the carbs...

there were 3 versions of the RD400... C/D were the same.. E model in 78 was basicly a hot C/D ..Had a little plastic tail unit on
the rear of the seat with a all matt black engine..
Then the F/G.. had the one peice head with the ram air cooling...
So what I'm saying there maybe 3 diffrent carbs for the RD400 range...Cheers.
I've never owned an RD350 and the RD400D I had was minutely disassembled into apple boxes when I got it. Everything was disassembled completely. Pity nothing was labelled... :facepalm:
Therefore I have no idea about models and carbs etc.

I'm pretty sure the bottom are RD350LC though... I'll check the main jet - if there is one. Thanks.

EDIT:
Top: 110 main, Stamped ISO 278 A(T?)
Middle: ? main, Stamped 2R9
Bottom: ? main, Stamped 4L3

[pete-blen]

Cheers.
I've never owned an RD350 and the RD400D I had was minutely disassembled into apple boxes when I got it. Everything was disassembled completely. Pity nothing was labelled... :facepalm:
Therefore I have no idea about models and carbs etc.

I'm pretty sure the bottom are RD350LC though... I'll check the main jet - if there is one. Thanks.

EDIT:
Top: 110 main, Stamped ISO 278 A(T?)
Middle: ? main, Stamped 2R9
Bottom: ? main, Stamped 4L3


just had another look at the pics...
I'm sure the middle carbs are RD350 and a VERY early one.. maybe even R5 carbs.. R5 had a drum front brake.. Yamaha put a disc on it then called it the RD350....
WHY...................
The middle carbs seem to have the veiw port in the side so you can see the dimple in the slide for carb balanceing & oil pump setting...
only very early Milkini had that veiw port/hole..
And they also look as if they have to oil feed spigget from the pump in the carb... RD400 / RD350LC had the oil spigget in the
intake manifold..

[Kickaha]

.. RD400 / RD350LC had the oil spigget in the intake manifold..
LC goes into the carb body just before the inlet manifold

http://www.rd350lc.net/4L0engine81.JPG

[pete-blen]

LC goes into the carb body just before the inlet manifold

http://www.rd350lc.net/4L0engine81.JPG

O ok..maybe its the other way around then...

[Skunk]

Current research says...
Top: R5 350 A/C - 2.0 cut away vs 2.5 for RD's
Middle: almost certain RD400
Bottom: RD250LC pretty sure. Still gonna check that 4L3 number though.

[GrayWolf]

350LC carbs will have '4LO' stamped on them

[Rcktfsh]

just had another look at the pics...
I'm sure the middle carbs are RD350 and a VERY early one.. maybe even R5 carbs.. R5 had a drum front brake.. Yamaha put a disc on it then called it the RD350....
WHY...................
..

They did a little more than simply add a disc,RD engine has reed valve R 5 piston port, RD 6 speed R5 5 speed approx 5 hp more than the r5. R5 carbs have brass slides and these are interchangable with the RD, was a good swap over as it cured the RD's sticking throttle problem in cold wet weather.

[malcy25]

Top: 110 main, Stamped ISO 278 A(T?)
Middle: ? main, Stamped 2R9
Bottom: ? main, Stamped 4L3

The three Digit codes are yamaha model codes....and usually stamped near the choke mount/boss on the carb
278 is Early 54mm stroke horizontal split case Yamaha -R5 type thing (RD 350AC was 328)
2R9 is RD400E-F
4L3 is probably a mistype of 4LO which is 350LC

Any one with 3G3, 1X2 and 409 stuff, send them my way....!!!!

[Skunk]

Top: 110 main, Stamped ISO 278 A(T?)
Middle: ? main, Stamped 2R9
Bottom: ? main, Stamped 4L3

The three Digit codes are yamaha model codes....and usually stamped near the choke mount/boss on the carb
278 is Early 54mm stroke horizontal split case Yamaha -R5 type thing (RD 350AC was 328)
2R9 is RD400E-F
4L3 is probably a mistype of 4LO which is 350LC

Any one with 3G3, 1X2 and 409 stuff, send them my way....!!!!Cheers malcy25. It's no mistype. Very clear and on both carbs. I have found them mentioned in a few places on RD forums but nothing specific to tell what they come from.

[RDjase]

Cheers malcy25. It's no mistype. Very clear and on both carbs. I have found them mentioned in a few places on RD forums but nothing specific to tell what they come from.

I found 4L3 listed for RZ250 1980 to 1986 on a jap site, had pics of LC's since all water cooled RD's were RZ's in Japan