RD350 Stock Jetting

[Diablo007]

I'm rebuilding carburetors for an RD350.  Current main is a 160, main in the rebuild kit is a 140, manual shows main as a 130.  Needle is a 5I4, manual shows a 5J6 in 3rd position, if I'm reading it correctly.  Also, where do you count clip position from?  Furthest from the point?  Closest to point?  It's been a while.

[Yamaha 179]

The Service Manual calls for a 5I4 in the 3rd position and a 140 main jet.  Also a O-8 needle jet and a 25 pilot jet.  That was for a stock machine and gasoline back in the dark ages.  The 3rd clip position on the jet needle is counted from the top.  YMMV.
Lyn Garland

[quocle603]

Check out the manual. All the information is on there.

Jetting will vary from bike to bike depending on who's hands have been in there. What is your current set up for carbs, filter, and etc. The clip position, you should be in the 3rd position and work your way either up or down depending on how your bike runs and rides. UP IS LEANER and DOWN IS RICHER. 

[m in sc]

ALSO DEPENDS ON YEAR AS  air filter changed in 75 dropping stock jet to a 110. this is the baffled filter. typically on us spec bikes WITHOUT A BAFFLED FILTER, it was 140 main. Use a genuine jet, do not use the needle or pilot out of the rebuild kit. The needle is a probably a yl2, which is a copy of the uk 75 350 needle which does use  a different carb. Im dead serious. use the originals.

[quocle603]

https://www.jetsrus.com/ is a great site for genuine mikuni parts. :)

[SoCal250]

Sudco is also great place for genuine Mikuni parts
https://www.sudco.com/

[Diablo007]

Thanks for the input.  Carburetors are high tops, can't remember where they came from, either from the parts RD350 or found loose in the shop.  Current setup is stock airbox with K&N filter.

Rebuild kit is Sudco but bag with parts is labeled Keyster, bought from Economy Cycle.  I do have the Mikuni parts though: 5I4 needles, 140 main jets, 25 pilot jets, 25 valve jet.  Should I remove the needle jet and check it?  If so what is the best way to do so?  Just tap out from the bottom?  I'm guessing there's an o-ring seal that will need to be replaced, but don't see one in the kit.  Starter jet? I'm guessing that's related to the choke?

Both my Yamaha manuals are part number SVM-360-0800-20 (one soft copy, one hard copy) and have the info posted by quocle603.  The Rajdoot 350 manual I have (soft copy) lists the info Yamaha 179 gave, except with the clip in the 4th position.  Seems like the logical starting point.

[m in sc]

use the mikuni parts.

definately pull the jet tubes and clean them.

with a k&n in the box, a 150 or 160 sounds right.

[SoCal250]

Thanks for the input.  Carburetors are high tops, can't remember where they came from, either from the parts RD350 or found loose in the shop.  Current setup is stock airbox with K&N filter.

Rebuild kit is Sudco but bag with parts is labeled Keyster, bought from Economy Cycle.  I do have the Mikuni parts though: 5I4 needles, 140 main jets, 25 pilot jets, 25 valve jet.  Should I remove the needle jet and check it?  If so what is the best way to do so?  Just tap out from the bottom?  I'm guessing there's an o-ring seal that will need to be replaced, but don't see one in the kit.  Starter jet? I'm guessing that's related to the choke?

Both my Yamaha manuals are part number SVM-360-0800-20 (one soft copy, one hard copy) and have the info posted by quocle603.  The Rajdoot 350 manual I have (soft copy) lists the info Yamaha 179 gave, except with the clip in the 4th position.  Seems like the logical starting point.

Yamaha USA service manuals usually have a part number "LIT-xxxxx-xx-xx". The "SVM-" manual may be from a different region or printer/supplier?
The 5I4 needle mentioned above by Lyn is correct.

[SoCal250]

I just posted the Tech Bulletin about the filter & jetting change that Mark mentioned above. (Thought it was already in the Tech Library but discovered I hadn't posted it yet. In any case, it's now available. )

THE TECH LIBRARY »Yamaha Factory Specs and Info »Yamaha Technical Bulletins

[Diablo007]

Thanks for all the info and tips.  I removed the needle jet as advised.  I was shocked at the crud around it in one of the carbs.  The needle jet is numbered 1750-8.  I'm guessing that's a 0-8.

As for the manual(s) the number I posted was on the front cover of both.  The back cover of the hard copy has the number LIT-11613-60-20.  The soft copy I have does not have the back cover as part of the file.  I'll add the tech bulletin to my library.  Thanks.