Gas smell in oil

Hey everyone. Back at it again. Been having a hard time starting the bike. It would backfire when I let off the starter switch. Figured I would pick up a new battery, because I read it might not be strong enough to fire the bike, and try again. I can smell gas in the oil, and I'm sure this is not good. Draining the oil as we speak. I was using an auxiliary gas tank because I have petcock issues. I had an old lawnmower tank hanging, and filling straight to the carbs. Any idea why I would have gas in the oil?

 

The float needle and seat are not sealing properly...letting fuel escape out of the bowl and making it's way through the engine and into the oil sump. Backfiring probably related is my guess.

 

I kinda figured it would be the needles. I soaked everything in carb cleaner, including the needles. Lesson learned.

 

Sometimes a few taps with a screwdriver will seal them. I've read lapping compound does them good as well...or are they rubber tipped? What kind of bike? Model?

 

They are rubber tipped. 1982 650 Maxim

 

Yup lesson learned...carb cleaner eats rubber.
5N9?..with YICS

 

It is a YICS engine. Not sure what 5N9 is though.

 

Taking off the clutch cover as well. Might as well do the whole thing?

 

The question was out of curiosity. 5N9 is a model code.

It's on the neck as part of the VIN.
If it's a short VIN (9 digits) it will be the first 3 digits...5N9010101
If it's the long VIN (17 digits) it will be digits 4-6...JYA5N9003etc

It's also on the engine...first 3 digits. I think they are always 9 digits. Should match the frame unless the engine is not original.

If it were me I wouldn't bother...unless it's leaking.

 

1982-83 XJ650 Maxim Canada: 5N9

 

Yup 5N9.

Excuse the wood chips there, from when I was putting the carbs back in.

 

Is there anything else I should be looking for?

 

Might be a stupid question, but should I change the oil filter?

 

I would, for piece of mind.

 

Carb cleaner eats rubber? Maybe, but it shouldn't because it's petroleum based. Aand the float valve tips are not rubber, they're Viton I believe. Does it eat viton?
Someone correct me if I'm wrong please.

 

Viton is a trade name (Dupont, I think)...it is a synthetic rubber. I don't know if the float needles in the XJ's are "Viton" but surely they are a synthetic rubber of some sort. http://www.xj4ever.com/catalog/c-hitachi.html

Just because it is petroleum based that doesn't mean it's safe for all chemicals...
Viton has poor resistance to acetone, esters, amines, organic acids, acetic acid, MEK, ethyl acetate, highly polar chemicals, etc. https://www.calpaclab.com/viton-chemical-compatibility-chart/

Since many carb cleaners are proprietary it's almost impossible to know what chemicals and what proportions are "in the soup".

Personally I've found that soaking rubber (synthetic or otherwise) in carb cleaner has yielded poor results.

 

Yes, I was thinking about this whilst watering the greenhouse, my use of carb cleaner is in spray can form, and it is petroleum based. The soak and wait stuff could be anything I guess.

 

I'm still going to change them, because the rubber feels a little stiff, so they might not be sealing that well.

 

If in good shape, stiff is good. That is why solid metal needles work. They should only not seal is they are worn or misshaped. Normally worn would look like a ring or groove where the tip mates. Replacing should remove all doubt though.

 

So I took the clutch cover off, cleaned whatever there was there for gas in the cover, reassembled. Everything went well, but when I pull the clutch lever, it has almost no tension. What did I do wrong, or is there something I am missing?