Fuel in my oil and air box

[Paul G]

I have an 82 XJ 1100. We got the bike out of the corner of the garage this week. Noticed fluid leaking on the floor. It was fuel leaking out of the exhaust crosover pipe. also the oil level was way above the window.

Upon some investigating found fuel in the airbox. A little more than 4 quarts of oil drained out of a 3.4 quart crank case. Am I right in assuming the float valves or floats themselves are not shutting off fuel flow?

I removed the carbs from the bike last evening. The right hand fuel tank pet cock was not shutting off 100%. It dripped a little fuel out even in the off position. I assume it allowed fuel to overflow one or more of the carb bowls.

Talking to the dealer service guy this morning he said that there are fuel filters on the petcocks inlet, inside of the fuel tank. He said they have a tendency to shrink and dissintegrate over time. I am hoping that some crud got in the bowls and clogged the float needle and seat. (I have been curious as to where the fuel filters were. I never found any inline filters since I have owned the bike)

Can I put filters inline? There are only 2 fuel lines going to the four carbs.

Did I pull the crbs for nothing? (what a pain)

[RiskyBusiness]

It's in the inline filter tech tip.

[Jerry]

Paul:

Carb issues are a recurring topic. You might try the Search function, tab is at the top right hand of your screen. Lots of discussion, techniques noted in various posts. Search on 'carbs' or 'leaking carbs' or 'octopus'. You will probably get more information than you want......

Check the Tech Tips section of the XS11.com site as well; direct link to this area is on left side of your screen. Several carb articles here, plus links to other information. Don't overlook the Off-Site pages; lots of good stuff there!

To answer your question in brief:

Problem is in 3 areas. Bad inlet needle/seats in the carb, problems with the 'octopus' and plumbing that uses engine vacuum to allow fuel to flow only when engine is running, and petcock diaphram/"O" rings defective. Other posts and Tech Tips address all these, plus adding in-line filters (are none on the XJ) and cleaning your fuel tank. Some people have replaced the 'octopus' entirely to simplify the plumbing under the tank.

Note there are minor differences in the XJ carbs to earlier XS carbs, mostly in jetting and choke assembly. However, XS Specials from '80 and '81 use the same 'octopus' and petcocks as the XJ, so posts about these models will be useful.

[xssiveone]

Two reasons why you leaked fuel from the carbs... 1)vacuum operated petcock valve didn't close, and 2)one or more needle/seat (float valve) also didn't close. Both should be operating properly in my opinion. If nothing else, the carb bowls should be removed to check the float valves.. maybe you will get lucky and it will just be a bit of plastic or crud that kept the float valve from closing. I doubt it tho as there are tiny screen filters on the top of the float valve and nothing should have gotten thru them big enough to hold the valve open.

Check the Tech Tips for Gary Lapook's method of installing inline filters.

[Paul G]

Thanks for the replies and the links. I have learned a lot. This site is invaluable.

I turned the carbs upside down and blew in through the fuel lines. The valves must be closing. I could not blow air in. So then I sprayed cleaner through carbs on the bench. Since the bike ran well before I pulled the carbs off I did not feel I had a sinking float. I also did the bench synchronizing trick using a drill bit to measure the throttle plate opening. They were not too far off but did need a slight adjustment.

I checked the vacuum operated valve. (octopus) If it is working properly it should alow flow from the two outside ports to the two inside ports when vaccuum is present. Stop flow when vaccuum is lost. It also seemed to be working properly.

I guess by turning the petcocks to the off position over the winter fuel may have flowed through the "prime" port directly in to the carb bowls. I dont normally turn the petcocks off.

I put it all back together this morning. Runs like a top. Better than before actually.

I guess I should either rebuild the petcocks or keep them in the "run" position and rely on the "octopus" to stop fuel flow.