Hoses coming out of carb outlet hose

Didn't know the proper name, but I am referring to the hoses that cross over from # 1 and #4 cylinder and #2 to #3.

The hose that joins #1 and #4 has a "T" fitting coming off it. What are these hoses for and where does the one from the 1/4 hose go?

Thanks
Al

 

What bike are we talking about here?

 

i've never heard of a bike having cross over hoses. they've always had caps. one should go to the fuel petcock to supply vacuum to the petcock. the other 3 should have vacuum caps. none of them should be connected to each other.

unless there's some type of system going on.

anyone else have a clue as to why he's got what he's got?

 

Sorry, it's a 1989 Yamaha FJ600.

 

Heard of that. The only hose shouldf be going from Carb 3- to your petcock to create the vaccuum. The other boots should all have caps on them. These tubes are used for vacuum syncing your carbs...

 

There's a post on here somewhere about making a nonyics engine somewhat YICS with this method.

But eveyone else is correct. One to the petcock the rest capped.

 

Thanks much.
Out of curiosity why would you need vacuum at the petcock?

 

if you don't have a vacuum operated switch then you don't need vacuum at the petcock. the vacuum is what turns the switch off and on. and allows fuel to flow through. so when the bike isn't running. no fuel flows through.

vacuum operated switchs don't generally have an on/off position. they only have on/prime/reserve. when the bike is running. vacuum is applied to the switch to allow fuel to flow through.

 

Wow Thanks. That explains why the cock says pri. I couldn't figure out and thought it meant primary tank as opposed to reserve

Cheers
Al

 

If you run on "pri" you may be pushing. You'll have no reserve.

 

Not to mention if your floats aren't correctly set, you could flood your crankcase(oil) with Gas if left on Pri overnight. A lesson I apparently had to learn the hard way. :roll:

 

Hmmm so what happened?

 

If you're refering to Vedalkin's post, the oil filled with gas and had to be drained and the filter changed. Hopefully caught before riding as the gas will wash oil off of every surface it's supposed to be on.

 

fj600 - - someone may have noticed cracked/dryrotted caps and did a quick fix of connecting them like that- odd they chose to connect "opposite" firing cylinders (1,3,4,2).

Test your petcock - - pull the fuel line off, get a cup, get a length of vacuum line, and suck on it.
"ON" and "RES" should flow and stop without dripping.
"PRI" should flow all the time.

 

Which means it's a non-XJ type bike and this thread should be posted in "Other". I'm moving this thread to the correct forum.