Gas in Oil

I know I've read about this, but this bike is new to me (haven't even registered it yet), I just changed the oil, and it smelled strongly of fuel (and was about a quart high). Apart from the obvious (new oil/filter), should I do anything in the immediate future about it? It it because the PO left the petcock on PRIme for a year?


TIA
G

 

Yes this item comes up a lot. Basically you have a situation where one or more float valves may not closing tightly so as long as fuel can come down through the petcock it can get into the engine through the intake. In the prime position it can...

Its also possible that the vacuum operated diaphram valve in the petcock is bad and fuel can be leaking in through the fuel and or vaccum line when the engine is stopped.

Drain and replace the oil but ultimately you need to fix the carbs and/or the petcock.

 

Thanks for the info. I'll add those to the slowly shrinking list....

 

You might also wan't to flush your oil by filling it up, letting the bike run for a couple of minutes and then draining everything out and replacing you filter and oil.

 

When my just purchased Maxim did the same thing, petcock failure and float sticking from lack of run time, I ordered my petcock repair kit first and then changed out the oil/gas in the crankcase (oil was definitely dirty) with just some cheap 10-40. After rebuilding the petcock the first thing I did was take the advice of this forum and run half a can of Seafoam through the tank. Basically drove the bike around a hundred miles and then changed oil again, this time putting in the good stuff (Rotella T if I recall/spell correctly, there's a not too distant thread on it). The oil that had a hundred miles onit was actually not overly dirty, I guess because the couple extra quarts of gas that had gotten mixed in helped clean out some of the original crud. Fortunately I didn't put but maybe 25 miles on the bike with the diluted oil before I noticed the problem.
Since then the gas hasn't been getting past the petcock when stopped and left in the RUN position, or else the Seafoam helped unstick what was gummed up in the carbs, or both!

 

Where in the North-East Stooge:

Anywhere near my World Headquarters for XJ Carb Cleaning, Rebuilding and Super Fine-tuning on a budget!

Shop is shrinking again.
Daughter lost her lease.
Moving home.

Anybody want to hazard a guess as to where all her stuff is going to be placed in storage.

The upside is I get a REAL comfortable chair down in the shop!

 

In Wester NY, Buffalo area. The more I mull it over, I'm thinking about taking the carbs out myself and trying to clean them. Frankly, I'm intimidated by carbs. FI I get, but carbs seem more like magic to me...

What is this Seafoam, and Where could one get some?
Any great advice on what not to do when taking out my carbs? It's only been a year since the bike was run, is there a chance the seafoam may unstick whatever is stuck?
Is the petcock rebuild kit a Yam dealer only item?

Thanks again....

 

Greg:

In answer to your original post, if the petcock was left on "PRIME" that is the same as leaving a conventional petcock "ON", so yes, that could be the reason there was gas in the oil.

So I would switch the petcock to the "ON" position, change the oil and filter, and give it a try before you take anything apart.

In a perfect world, your float valves would shut off fuel flow even in "PRIME", but there's a good reason these bikes came with vacuum-operated petcocks that flow only when the engine is running (when in the "ON" or "RESERVE" positions), and why the first rule on any bike with a conventional petcock is to switch it off when you shut her down. In our imperfect world even good float valves don't always close completely.

When you try it in the "ON" position, you may want to leave the cover off of the airbox so you can see/smell gas overflowing, and you can tell which carb is the culprit. Sometimes tapping on the float bowl will free up a stuck float and shut off the flow.

Some Seafoam couldn't hurt, if you also want to try it. It's available at AutoZone, and probably other parts houses.

Good luck, and keep us posted!

Herb

 

Thanks. Very helpful.

 

Carbs are Fuel Injection without the Electricals.

Manual everything. Not to hard to understand when you have the time to analyze what's going-on in there.

 

The abicus is a computer without electricity. I get it!

Seriously, my love of things mechanical makes me want to be able to work on carbs, but they still mystify me. All those tiny precision parts working perfeclty together to make fire. It's like the tao, FI focuses on the way to make the fire, carbs insist fire is the way.

I ramble....