octy to carbs

[Jelmo11]

Ok so I feel kinda dumb but I took my carbs off and cleaned them/rebuilt them and now I forget where the fuel lines go and how they are ran the bike is a 79xs11 special so it does have an octy and id like to keep it so can anyone. Please help on how tto run the fuel lines again please

[CatatonicBug]

There should be a diagram under the seat.

Otherwise, the far left port on the octy (we'll call this #1) goes to the front of the left petcock and has a splitter that runs to the left connection between carbs 1 & 2. #2 goes to the rear of the left petcock. Port #3 connects to the rear of the right petcock. Port 4 runs to the front of the right petcock and has a splitter that runs to the right connection between carbs 3 & 4.

Be VERY careful about the length of the lines. If you are replacing them, ALWAYS use the old lines as a template to cut new pieces exactly the same lenngth as the old ones. Even 1/2" extra can cause the lines to kink.

[jetmechmarty]

I modified mine just a bit. I found brass tee fittings at my local hardware store and replaced #18 with them. I also crossed line #20. I ran the left to the right and the right to the left. This gave me more room when taking the tank on and off. (#20 goes to the tees between the carbs) I used new hose and clamps sourced from Mike's XS.

I installed these between the carburetors:

[fredintoon]

Ok so I feel kinda dumb but I took my carbs off and cleaned them/rebuilt them and now I forget where the fuel lines go and how they are ran the bike is a 79xs11 special so it does have an octy and id like to keep it so can anyone. Please help on how to run the fuel lines again please

Hi John,
now you've seen the fuel line diagram that Marty posted you may realize why my SG's octo was long gone before I ever got the bike.
Not that it don't work, it's that dumping the thing and using 2 lines instead of 8 is a great example of "Simplificate and add lightness."

[crazy steve]

Be VERY careful about the length of the lines. If you are replacing them, ALWAYS use the old lines as a template to cut new pieces exactly the same lenngth as the old ones. Even 1/2" extra can cause the lines to kink.

Yep, that's a true story... It can be a real nightmare getting all those lines routed and kink-free, that's the big reason the octy disappears so often...

[Edisto]

I am fighting that demon now with fuel line length. ARGGGGGF

[jetmechmarty]

I am fighting that demon now with fuel line length. ARGGGGGF

That's why I went from the left fuel cock to the right carburetors, and the right fuel cock to the left carburetors. It was the easiest way to get the installation free of kinks. Also, my brass tee fittings take up more space than the original plastic ones. The final product is nice and neat. (as well as it can be with all those hoses)

[Jelmo11]

Ok guys thanks for the help on octy to petcocks but how do I hook my octy to my carbs. Proplerly ?

[Jelmo11]

Is it 20 and 19 to. Carbs??

[bikerphil]

20 is the two fuel lines to the carbs and 19 is the vacuum hose to the #2 carb boot port.

[Jelmo11]

Ok so I have the lines ran from the octy correctly and now I'm stuck my carbs have. 4 ports on them two between the 1 and 2 and 2 more between 3 and. 4 they both have one upper and one lower but what ports do line 20 go into and what are the other two for and I have a hose coming up from what I think is a crank case is that a vent I'm so lost sorry

[JasonRedbeard]

Fuel lines run to the lower T ports between the carbs. Upper T ports are bowl vents and should each have a hose running to a nipple on the air filter housing (assuming you still have the stock housing.)

The bigger 1/2" or so vent hose from the engine case also goes to the air filter housing.

[natemoen]

Fuel lines run to the lower T ports between the carbs. Upper T ports are bowl vents and should each have a hose running to a nipple on the air filter housing (assuming you still have the stock housing.)

The bigger 1/2" or so vent hose from the engine case also goes to the air filter housing.

+1 He has you covered for those.

[fredintoon]

Fuel lines run to the lower T ports between the carbs. Upper T ports are bowl vents and should each have a hose running to a nipple on the air filter housing (assuming you still have the stock housing.)
The bigger 1/2" or so vent hose from the engine case also goes to the air filter housing.

Hi John,
in addition to what Jason sez; there's the possibility that a dreaded PO Frankensteined a later model airbox onto your bike. Check the spigots the carb vent lines hook up to, the later models have a different carb vent system, there are no upper vent lines and the air box spigots your vent lines plug onto are not bored through. It's the same plastic moulding so you can drill them through yourself.

[KA1J]

Hi John,
now you've seen the fuel line diagram that Marty posted you may realize why my SG's octo was long gone before I ever got the bike.
Not that it don't work, it's that dumping the thing and using 2 lines instead of 8 is a great example of "Simplificate and add lightness."

How do you keep the same petcocks and simplify the routing? I know you can change petcocks and make it simpler but how to keep the existing ones and still have run, prime, reserve & off available?

Gary