Stuck float valve Questions: 1982 XJ650RJ Seca

Just bought my second 650 Seca (sold the last in 1999 and am just getting back into bikes). Bought it on Saturday and am super stoked. Went to ride on Sunday and ran gas out of the airbox. I can see that this is a stuck float but I have some questions. Pardon the detail but I think it's necessary. Took out the air filter, looked down in and turned the petcock to both on, then reserve, engine NOT running. Gas was not coming out of the crankcase breather connection to the airbox, so presumably just out of the carbs. Turned it to OFF, and it stopped.

1 My petcock is labeled On, Reserve, and off. No PRI, and it ran without vacuum, So I assume it is NOT a vacuum petcock as would be stock. Is this correct?

2 It is unclear to me how the gas would go down into the crankcase before it goes out the drain in the airbox. It does not look like it ever would so I don't understand how the oil would become contaminated unless the drain in the airbox got plugged first. It sounds from the forum as if the gas takes a more direct route to the crankcase and then to the airbox. Could someone explain that? Can I pull a sample from the drain plug and smell for gas to diagnose?

3 If filling the crankcase is such a problem then would it make sense to remove the breather hose and install a breather filter of some kind directly on the crank case instead? (I assume plugging the airbox where the breather hose connects would be necessary if this was the case).

Thank you in advance. I believe what I will do is pull the boots from between the airbox and the carbs, turn the petcock to ON, and look at which carb is leaking. I will then tap the float bowl and see if that helps and monitor.

And yes, despite a stuck float, I am still super stoked, because I own a 650 Seca!

 

take another look, the carbs are sloped to the engine. the air box is higher than the carbs. it's usually oil in the air box from too full crankcase because it has gas in it.
that hose is a crankcase vent, remember PCV valves on cars, same thing, keeps the engine clean and the EPA happy

 

Thank you for your response!

So the route is through the cylinder, that makes more sense, though it immediately comes through the airbox if I turn on the petcock. Maybe because my driveway slopes?

I will definitely take an oil sample and have my wife smell it (I have a poor sense of smell) for gas. Should I just plan to change it regardless? This happened while starting (Or perhaps right before shutting down) so the engine didn't run much.

Also shows that my thoughts on removing the airbox/carb boots, turning on the petckock, and watching which carb starts to pour it out isn't a sound method for diagnosis because it might be going through the engine.

I guess this answers the idea about the direct breather on the crankcase!

 

just go ahead and change the oil but your going to need some level ground to check the oil level with the sight glass
there's two places to drain oil, the only one you need is under the filter. the other one, under the engine only drains a few ounces, is hard to get at and tends to strip the bolt or case, so forget about it

 

Thanks for the heads up on that second drain, I would hate to strip a plug. Should I do an intermediate oil change to make sure there is no gas left, and if so can I use any old cheap oil?

 

i think once it's changed there's not enough gas left to worry about, it will turn to vapor and blow out when it gets hot.
a vacuum petcock is the way to go for this kind of thing, it just makes things simpler.
send a email off to info@xj4ever.com
mobil delvac 1300 in case you were wondering

 

Thanks for all your help, I really appreciate it! Looks like that's a semi oil, a cheaper alternative that works as well as the Yamalube I take it?

 

And if you ever get to Minneapolis let me know and I'll pour some homebrew!

 

Any oil that has the correct certifications (in this case, JASO-MA) will work fine. There is active debate about synthetic or not.

Nice to see another forum member from the Twin Cities!

 

Yes, it's an aftermarket non-vacuum fuel valve.

 

Indeed! And thanks for the help!

 

Polock, is mobil delvac 1300 what you run all the time? Looks like it's marketed for semis.

 

shell rotella t4 is also desil truck oil

 

i use it in the yamaha, suzuki, bmw, kia, cub cadet and old push mower. it's worked for a long time

 

I searched the forum after I posted and saw the discussion, shoulda done that before posting, I apologize.

For the record, the oil did have gas in it. I am hoping the overflow was when I parked it and not while I rode home from the purchase, an hour plus ride....

 

if it over flowed when you parked it you still have issues that need to be fixed.

float valves should stay sealed when parked. unless you have a manual petcock the vac petcocks stop flowing too.
so with a good petcock and bad not sealing needle the fuel in gas line will flow into carbs for an overflow at most.

if petcock is bad fuel can flow down vac line into motor and into carbs but only if there is a leaky valve.

 

I know I need to fix the floats. Manual petcock (turned it off overnight, gas overflow from airbox happened when I turned it on and cranked the engine to start the next day.). I was just meaning I hope I didn't ride it with gas in the crankcase.