Needle jet part #

[Mr Fixit1996]

Can anyone tell me why yamaha put different needle jets in the carbs ? 1 and 4 have a different part # than 2 and 3.
I have a 1979 xs 1100 sf model and i want to replace them with New ones. Can anyone tell me the part # s
Best wishes, Dustin

[petejw]

Yamaha put different emulsion tubes in the center
2 carbs 2 run them slightly richer, to keep the inner
cylinders cooler, so dont go mixing them up, not sure
if they did this with all the carbs thru out all the models.
sorry cant help with part numbers.

[Mr Fixit1996]

Ok that sounds like it makes since, Thanks.
Dustin

[psycoreefer]

I just recently got new emulsion tubes and I can tell you it made a huge difference, although my old ones had visible damage and 40k miles. I couldn't find a source for the center tubes, the 301 X2's, so I put the same tubes in all four carbs. Bike is running well but still has a bit of a flat spot just off idle. If you do a search for emulsion tube you should find a thread where I posted the two sites I found that sold new ones, as well as the part number. They are expensive! Your other option is to get tubes from mikesxs, they are not the same as yours but will work with some re-jetting and experimentation. With some searching you should find a thread on that as well.

GOOD LUCK.....