Fuel leak/ first post

This is my firs post so I figured I would introduce myself first before I ask my question. I am a part time mechanical engineering student, and a full time ford tech at a local dealer (I absolutely hate fords but they break down all the time which brings me business). I love motorcycles and just about anything else that would be considered dangerous but I haven't owned one in some years after an accident left me with a broken femur and some 300 stitches and staples. I have recently decided I wanted another bike so I went out and bought two Yamahas off of craigslist for cheap. I picked up an 88 virago 1100 and an 85 maxim 700 (current pictures below).

Now to the question: My recently purchased xj700 has a fuel leak from the hose that comes off of the t fitting between the #3 and #4 carb, it only leaks when the bike is running at idle and goes away once you build some rpms. I took the carbs off (actually took everything off the bike) and opened the bowls to check the needles and they all appeared to be in good shape but do not know what the float height should be or if the fuel level in the bowls even have anything to do with the leak. In the picture of the carbs below it is the upper hose inbetween the two carbs on the left (the carbs are currently upside down). Thanks in advance for any information.

 

Welcome to the site !!

The 3 fuel pipes in the "fuel rail" have 6 "O" rings, which don't cost much.
You have to break the rack, and since you are a mechanic, you might want to get the 8 throttle shaft seals at this time. 4 Pilot "O" rings too, all available from Chacal - XJ4ever, top banner on every page. every day.

Most carbs need a 3MM float level, set with a clear tube.

 

I have an excellent blow by blow pdf on how to do this, I believe from Chacal (given the XJ4EVER.COM copyright at the bottom as well as the various XJ4Ever part numbers listed) which will show you how to set your float levels and the specified measurement for the different carbs are listed at the end. His tools will make life easier, but many fabricate their own. As an ME student and mechanic I have my suspicions which way you will go ... Problem is, even zipped the file is too big to post (700K) and I am not finding it elsewhere on the site. Send my your email by PM and I will get it to you.

For a carb rack, you can be creative with pvc like in the article or grab some scrap 2x4s or 2x6s and a few nails/screws/what have you ... Just be certain it is square and level.
Also see http://xjbikes.com/Forums/viewtopic/t=2908.html as well as
http://xjbikes.com/Forums/viewtopic/t=14692.html for a great deal of helpful information for dealing with your carbs.

 

You can find the carb level write ups at xj4ever.com. they are at the bottom of the page.

 

Thank you all for the information everyone

It isn't leaking out of the "fuel rail" that links all four carbs, the hose that the fuel is coming out of is attached to a t-fitting that is above the "fuel rail" and only connects the #3 and #4 carbs, the #1 and #2 carbs have this same fitting in between them but there is not a corresponding fitting between the #2 and #3 fitting.

 

OK - that's an overflow vent, and that means you need to service your floats - needle - seats as you have a carb overflowing.

Easy work

 

Awesome, I thought the floats were probably the issue just wasn't 100% sure if that was an overflow hose or not.
Thanks for the info