emulsion tubes

[mack]

Haven't found anything in the books with regards to models and tube numbers. I have a few here, some are 300-x2 and some are 266 x2 and I'm sure there is more, as, if I remember correctly, 2&3 on my SF were different from one and four. Anyone have some insight on these. Trying to figure out if PO had changed the emulsion tubes to account for using the wrong jet needles.18's instead of 16's with the 300 x-2 tubes.

[crazy steve]

Mack, I don't have a '81 FSM so I can't tell you what should be in there. But my understanding is the tubes and needles need to be 'matched' in order to get the right mixture at a given throttle opening.

[mack]

Yea

That would be my understanding as well Steve. Just can't find out what number of tube match what needles.

[SFerinTEXAS]

What model carbs are you repairing? With the vent tees or without.

[GLoweVA]

According to the parts fiche, in the 81LH, all 4 carbs have the same emulsion tubes and needles, so, there shouldn't be any mismatched parts in there.
Some of these bikes did have different jets in 2 & 3 to richen them up a bit to keep them cooler, but again, according to the 81LH fiche, you should have all 4 the same.

Maybe the PO put 2 different carb sets together and that's why those internals are different.

Sounds like you've got a good mystery on your hands.

EDIT: Just looked at the SF fiche and saw that those carbs do have different tubes in 2 & 3, but they do have all 4 the same needles and jets.
Here's a link to all the Yamaha's fiche's:
http://www.ytcn.nl/archief/index.php...L%201950-1996/

[mack]

The

problem is the needle jets don't match the carbs. Steve and I both agree that the needles should match the tubes. What I'm trying to figure out is if the PO changed the tubes or just used the wrong needles. I went through the fishes today for every year but had little joy,then went to the vintage parts store. They had one needle in stock that will work, at least match the correct needles but I still don't know if I have the correct tubes. Will pull one of the original carbs apart tomorrow and check the tube number. If they match then I've wasted everyones time with this ridiculous issue. Why the PO put the wrong needles in will remain a mystery but may expalain why he parted the bike out. Yikes!!!! It just ocurred to me that I bought the head too. Hmmmmm. wonder what goodies that will yield.

[XS1100_OEM4ME]

Kits

There are so many carb kits that "claim" to have the right parts for different carbs. It is hard to tell what the PO bought or got and tried to use in those carbs? Many PO's get expert advice fromt their mech. friends and we end up trying to sort it all out Good luck with yours

problem is the needle jets don't match the carbs. Steve and I both agree that the needles should match the tubes. What I'm trying to figure out is if the PO changed the tubes or just used the wrong needles. I went through the fishes today for every year but had little joy,then went to the vintage parts store. They had one needle in stock that will work, at least match the correct needles but I still don't know if I have the correct tubes. Will pull one of the original carbs apart tomorrow and check the tube number. If they match then I've wasted everyones time with this ridiculous issue. Why the PO put the wrong needles in will remain a mystery but may expalain why he parted the bike out. Yikes!!!! It just ocurred to me that I bought the head too. Hmmmmm. wonder what goodies that will yield.

[bikerphil]

I've run into one set of carbs (late BS34-III's) that had wrong needles and tubes in there, the transition between pilots and mains couldn't be properly tuned, ran like POS. Put what is supposed to be in there and you really can't go wrong. Then you can figure out what jets you need for your application. JMHO, been there before.

[mack]

Yep

That's what I'm trying to do. Will advise tomorrow what the originals had in them.

[3Phase]

Jet Needles and Needle Jets

Here you go, Mack. These are the jet needles and needle jets from an earlier thread that I hope will help:-

Jet Needles

Needle Jets


The whole thread:-
Help Find A Cure for Crazcnuk's bike?

[mack]

Beautiful

Thanx 3 phase, thats what I needed. Saved me some time in the shop for sure.