FJ1100 Revival after 20+ years

[Cash Dereszynski]

Hello,
Brass Emulsion Tubes how critical are these, and what symptoms do they exhibit if they're clogged?
I cleaned and adjusted the carbs, installed jet kit as discribed,for foam air cleaners and aftermarket headers.
At almost 30 bucks a tube I'd like to be sure if replace them for good effect. How would you clean them as the holes are so small.

Cheers

Cash

[Pat Conlon]

These emulsion tubes (aka needle jets, jet nozzles) are critical to your engine running low to mid range, mid range to high rpms.
On street bikes, the majority of time your engine is using these jets..

Idle to low rpms = pilot jets and idle circuit
low, mid and mid high rpms = needle jets
High rpm, WFO = main jets

See the graphic at the attached pdf:  http://www.fjowners.com/index.php?topic=47.0

They must be clean...all those little holes open. Soaking them in lacquer thinner then using compressed air helps. Cleaning the scale off the inside with a nylon spiral brush helps. Using a thin strand of 18 gauge wire can help clear the stubborn clogs. Another point to check is the wear on the bottom opening from the needle. After time, the needle vibrating against the inside of the tube will cause elongation of the lower opening (next to the main jet) which will cause all kinds of weird over rich idling low speed symptoms.
Here's some discussion from the Factory Pro website:   http://www.factorypro.com/products/Jets,%20Mikuni,%20buy.htm

Also, FYI those emulsion tubes in your picture are the wrong tubes for your '84 carbs... contact Randy at RPM for the correct tubes

Hope this helps