Air Filter housing&hoses

[xs11jack]

I just bought a 1978E. Sat for 2 years and the carbs were black gunk inside. After cleaning the carbs, I look at the manual for the proper hose routing. Since I have a 80G parts bike I looked at the air box and observed that the two spickets that the two vacuum hoses go on are blocked, not drilled thru. The 78E, however are drilled thru. What gives here??? Also the manual states that the float setting is measured from the gasket surface! Does that mean the gasket must be in place to get the correct measurement or does it mean the the "gasket surface of the carb?"
XS11Jack

[prometheus578]

gasket surface of the carb... no gasket in place.
The 80G has the later style carbs. On the intake side of the air horn, there are four air inlets. Air jets for the main jet, pilot jet, air for the enrichener circuit and the last hole is to vent the float bowls.
The earlier model carb only have three holes. the bowl vent is that upper "T" between carbs 1+2 and 3+4. there is suppose to be fuel line type hose from the "T"'s to the airbox to vent the float bowls.
Do not plug these lines. If the carbs can't vent, the carbs will flood.

[jjwaller]

Re: Air Filter housing&hoses

Originally posted by xs11jack
I just bought a 1978E. Sat for 2 years and the carbs were black gunk inside. After cleaning the carbs, I look at the manual for the proper hose routing. Since I have a 80G parts bike I looked at the air box and observed that the two spickets that the two vacuum hoses go on are blocked, not drilled thru. The 78E, however are drilled thru. What gives here??? Also the manual states that the float setting is measured from the gasket surface! Does that mean the gasket must be in place to get the correct measurement or does it mean the the "gasket surface of the carb?"
XS11Jack

The two hoses pointing up off the carbs,
the upper "T"'s, are carb vents, Run them to the 2 fittings on the airbox.
As prom said, measurements are from the base of the carbs. However, I usually assume the gaskets are a little over 1mm thickness. Works fine if the gaskets are adhered to the bases. Probably tear them up if you try to remove them. SO if they are in good shape leave them alone and just add 1+ a little bit to the measurement.
By the way, Welcome to the best and fastest XS11. It Rocks!

[xs11jack]

First, thank you. I tend to get bogged in the details sometimes and waste a lot of time. The thing that remains with me is that if the 80SG were the bike I was working on, why are the carb vent hose going to an airbox that looks like the air holes were never drilled thru even from the factory!
O.K., I plan on using a dial calipers to set the intial float hieght and then with the bowls on, use a clear hose to the bottom drain hole to see if they are singing the same song(hieght wise). Are there any flaws in this plan??
The reason the 80SG is a hanger queen is that the frame does not have a title. The bike is probably a rebuilt accident victim. I supposedly can get a title thru some outfit in Los Vagas for about $150. But that money could go a long way to spruceing up the 78E. I suppose finding a bare frame is next to impossible. Oh, well, I can dream.

[jjwaller]

The fittings on the airbox look like they are not open, but they are in fact open.
Hook some tubing to them and blow through it. I think they are orifices or filtered, or something, (never looked into it), but yes they are in fact open.
This is of course on the 78, Have no idea
what is on the 80. Aren't the 80 carbs BS34 III and have the carb vent in the inlet. Know the 81's are, not sure of the 80's.
John

[John]

The carbs on the 78-79 used the upper set of T fittings to vent the float bowl to the airbox via the small nipples on the top/front of the airbox. The 80-81 carbs eliminated the upper T fittings, and relocated the bowl vents into the intake side of the carb. The airbox on the 80-81's has the nipples for the vent hoses, but they are plugged off. You must drill them out if you are using 78-79 carbs on an 80-81 bike.