Fuel in my oil

[egsols]

Last year had a problem with fuel in airbox on my 79 special. At that time I cleaned out the carb vents and problem went away.

After refueling and firing up this spring, it fired right up without any problems I might add, I'm finding fuel in the airbox and now also in the crankcase.

I pulled the carbs and checked for any sticking, misadjusted floats. Everything is nice and clean. All floats set to 25.7mm. The only thing that I noted was a little bit of fuel inside the number 3 diaphram.

Fuel tank shuts off, no leaks. Octo works but I have now removed it to make the plumbing work better.

With the carbs re-assembled, I held them upside done and blew into the fuel lines. Met with full resistence so I am assuming that the valves are doing their jobs.

Don't know what else to check out. Where can the gas be coming from?

[mason79]

coming from the carbs, change your oil

[79XS11F]

Fuel petcocks and or float needles are leaking. As stated ... change your oil and get the leak corrected.
Rob

[ross]

just an idea...

hey there egsols.....had the same problem with mine...nothing like a 7 quart oil change......hehehehe...anywho, heres what i added 2 mine to make sure i never have to do it again.....



got them at the lawn mower store for about $4 each.....when i shut the gas off, it is off....ross

[TopCatGr58]

Hey there Egsols,

You stated that the floats are the correct height, BUT did you check to see whether the floats may have developed any leaks??

That would cause them to sink flooding the carb. Also the float needles and seats are metal, and a small groove can get worn in the needle. Also fine debris can be getting caught between needle and seat! How OLD are the fuel supply hoses? You've bypassed the Octy. You said the petcocks were NOT flowing when off! The upper T's are properly vented and open! Are you running inline filters?

That's about all I can think of right now! Good Luck!
T.C.

[blue giant]

Ernie,

Remove the seat assembly and check the o-ring around the seat body. Mine were leaking and filled my crankcase full of fuel over the winter. I did not have my petcocks totally off.



Ordered new needles and seats, no more fuel in the air box or crankcase.



Paul.

[mason79]

yes topcat, the brass on my floats were so corroded from whatever, it took on fuel and sank, opening the valve, and this was after the po had it rebuilt by a yamaha dealership
mine were adjusted as well....

[egsols]

No leaks whatsoever from the petcocks. When they are off they are off so the fuel must be coming from what is left in the carbs.

When I had the floats off I checked them for leaks, couldn't find any. Shook them good, nothing inside, no wet spots. I didn't, however, submerge them to test for bubbles, but I'm pretty comfortable that they are okay.

I checked the needles under a magnifying glass, didn't see any grooves. They all look smooth. On a side note, the screens were in good shape and clean. In fact, the carbs looked real good, no shellac or debris anywhere.

Hoses look good, not certain of their age but will be replacing this week. No inline filters yet. Just replumbed yesterday so now I have room to put them in.

Upper tees free. Venting good, vents at airbox also free.

Oring around seat? Don't have one. Didn't they start putting them on in '80?

The only other thing I noted was that before cleaning some of the diaphragms weren't sliding a 100%. (They do now) If they don't go down all the way, when the bike is off, it is possible for fuel to be pulled up throught the main?


After I posted last night I went out and reinstalled the carbs. The bike started right up and runs great. I left the bottom half of the air cleaner off so I could reach underneath and check for any fuel in the air cleaner boots. They were dry. I'll check them again tonight when I get home. It only seems to happen if the bike hasn't run for awhile.

[blue giant]

Ernie,

Sorry, I forgot yours is a 79. I believe the seats screw in. Are they tight? Do you have the soft tip needle or are yours brass?

Paul

[egsols]

Hey Paul,

Yes, seats are tight.

Needles are neither, they look stainless but I'm not sure what they are made of.

[blue giant]

If it's intermittent then it may just be dirt. A set of inline filters may be all you need.

[thewiz]

Hmmmm ....

Other things could be: excessive float drop causing the needle to jam open ... OR .... float binding against the carb body. Shake the floats to determine if loaded or not .... bend the tab on the back of the float to change the drop if necessary.... I've never found the spec on float drop but it needn't move up and down too much at all .... move the float through it's full range while observing each pontoon making certain that it doesn't/wouldn't touch the carb body or bowl ....... I've found all of these conditions in XS carbs at one time or another.

[egsols]

I did move the floats to see if they were binding/catching and all of them seemed to be free.

Maybe there is a dirt issue but they looked real clean when I took them apart. The other thing that gets me is that it is intermittent and generally occurs after the bike has been sitting for a while. It also only seems to do it when the bike is not running. (I guess that's due to the fact that it would use any extra gas for combustion)

One thought, if the vents are slightly blocked that would cause excessive pressure in the bowls which in turn could force the gas up and out of the bowls throught the main jet?????

But.....if the vents were blocked wouldn't the bike run rough????

My buddy has a 07 KLR650 which quit running. He couldn't figure it out and was ready to load it in his truck for a trip back to the dealer when I noticed his carb vent hose had been melted shut from its routing beside the exhaust.

[DiverRay]

The vent being blocked CAN cause a lot of problems. I've worked on a bike that would leak after I thought I fixed and checked everything. Turned out there was some type of very thin material that had formed in the vent system. Once I used the spray can of B12 through ALL the carbs, it worked!!

[egsols]

Once I used the spray can of B12 through ALL the carbs, it worked!!

Hey Diver,


Excuse my ignorance but what's B12? Its not some sort of high folluting vitamin juice?

Sounds like what I'm going through. Where was it leaking?