Carbs

[MAKMAN71]

I took off my carbs about a month ago. I was wondering if I could get some help where the hoses go from the carbs. I have a hose on the left side of the bike from the cover on the side where the shifter is, does that one go into the carb. Whitch ones goto the boots and how many go to the stock air box. Thanks Mike

[nashville_bill]

What XS11 are you working on? The hoses are different on different years.

[John]

The hose that disappears into the left side engine cover is for the vacuum advance . It is attached to the small brass nipple on #2 CARB. Not to the nipple on the #2 intake boot, but the carb itself. That is ported vacuum for the advance. If you have a Standard model, the will be a vacuum line from #1 & 4 intake boots to the small nipple on the side of the petcocks. The larger hoses on the petcock feed the lower set of hoses that T into the carbs. The upper set of hoses that also T into the carbs will attach to the small ports on the top, front of the airbox, right next to the big crankcase breather hose. These are the bowl vents. It is important that you don't plug them off. They must be open to atmosphere.
On a Special, it's a little different. The petcocks are not vacuum actuated, and there are two fuel hoses on each one leading to the fuel distribution valve, or the "Octopus". It is located between the tops of #1&2 carbs. From there it is fed to the carbs through the same hose (lower 'T' fitting on carb)as described for the Standard. Heres where it gets wierd. Two of the fuel hoses are for the 'Prime' feature of the Special/XJ petcock. These hoses connect to the fuel lines that are exiting the octopus. The prime mode just bypasses the vacuum controlled octopus. Now, the vacuum line that actuates the octopus is connected to the nipple on top of the #1 intake boot.
Are ya good and confused yet? I hope not. It's really not very complicated, once you figure it out.

[MAKMAN71]

Carbs

I think I got it. I have a couple that you eliminated for me. By the way I have a Special I did not know there was a big diffrence. Actually the bike is my wifes. I just get to work on it and somtimes ride it. I drive a 2000 V-Star so I have to keep up with her.
Mike

[MAKMAN71]

Carbs

I was wondering if any one can help me. I got some great help bust still need more. I have a Special and was wondering where all me hoses go. On the side that has the choke on it I have 2 hoses that I think will go to the petcock and 2 (I think that will go to the air box. What boot swill have a hosees going to it. I think I have the middle 2 nipples on my carb boots without any caps on them and on the other side I have 1 line in the front by the ocotorpuse and I think 2 that go in to the airbox.
thanks for any info
this forum rocks
Mike

[John]

Mike, just re-read my earlier post, describing the hose function and routing. Look in the search engine here, and I believe there is a diagram showing the fuel hose routing, OR go to Yamaha's web site, and in the parts section, pull up your year bike and then on the left of the screen, there will a list of sytems. Locate the fuel system, and there is a diagram there also.

[Do Lee]

If you go to the maintance section on the forum home page and click on the carburetor section, the third post is about the hose hookups the two hoses pointing down hook between the #1 & 2 carbs and the #3 & 4 carbs. The equalization lines from the carbs hook to the airbox (depending on year model) The small hose off the diphram "Octopus" needs to go to the #2 carb boot nipple. The other 3 boot nipples need the caps on them. Go to the maintance section for carbs.
Its called:
Diaphragm Assembly (Octopus) Testing and Fuel Hose Routing Diagram

[Ken Talbot]

Here's the diagram again:

If you want to do a bit more reading on this issue, use the search button at the top of the page and look for 'routing'. Lots have people have been through this, and there are some tips on how to get rid of a lot of the plumbing.

[MAKMAN71]

Carbs

I just wanted to say thanks to every one that helped me out.
Made it a lot eaiser. All I have is the orginal Yamaha repair manuel for the bike and it did not tell me that info.
Mike

[bikerhawk]

OK, here's a question, from comparing the carbs on my F with those on my H...

On the F, vent lines come from tees between carbs 1-2 and 3-4 and go up to the airbox. On the H, those tubes in the airbox are sealed, and while there are no vent tees (fuel inlet only), there are tubes coming up from, I believe, the outer 2 carbs. Are these on the carb bodies supposed to be plugged, or are they not even drilled out? I never gave it much thought before seeing the F's setup...