EMULSION TUBE

[larryhobman]

Hi All,

Has anyone changed the emulsion tube in the carb.  I bought what I thought was a 20mm carb and I learned that it is just a bored out 18mm.  I just installed a new 72 kit and getting ready to tune it.  I have 3 carbs and I took the tube out of all 3 to compare and they are all different.  One has clearly larger holes and more of them and one has very few and smaller holes.  I am starting with a #90 main and #34 pilot.  I also, smoothed out the head imperfections in thee ports.  What is the best tube to use.  I live in sussex county delaware where there long open roads.  

[Fox]

I have never been into modding per se but I have read a lot of stories and it seems to me that the only way to tell for sure is trail and error testing with all of the tubes recording top speeds and checking the spark plug color using the same size main in all tests. If you have three or more fuel pins with differing tapers you can try those in sequence easily since the carb cap is always accessible. If you wanna try a few different mains then that's a lot of tedious work but in the end if you are methodical about it and record your findings you should be able to come to a reasonable conclusion as to what works best with your particular engine.

[90GTVert]

I'd stick with what's in the carb and not worry about the tube unless you can't get in tune with any combo of main jets, needle positions, and idle jets/mixture adjustment.

[scooterpimp]

Holy Crap im not the only Delaware guy here

[humanshield]

Hey Larry,

You got one of those fake 20mm carbs too?

The one I got was pure junk. Almost everything inside was messed up. The enrichment circuit didnt work, the pump jet circuit was foo barred and there were visible casting defects and one brass transfer tube was crushed during insertion obviously. Could never get the scoot to start with that carb. I'm gonna say someone is buying reject/defect carbs in bulk dirt cheap, machining 1/4 - 1/2 inch inside the outlet side to 20mm and calling that a 20mm carb.

It isn't.

Send it back and get a real 20mm carb from a reputable seller.

[larryhobman]

I HATE GETTING RIPPED OFF, FAKE 20MM CARB.

I was hoping to have a nice set up with a 20mm and the 72cc kit. I will try to move forward with this one right now. Ebay sucks sometimes. I now have all the tubes mixed up now and I do not know which of the three is the one that came with it. I plan on using the one with the most holes and a #90 jet to start and we will see how it goes.