Not good my friends, not good! MAJOR problems!

So as some people have seen I decided to "Bob" my xj650. I am on spring break right now and about to start a new job; so I've been busting my butt to get this thing running before I get too busy. All I basically did was strip everything down to paint and replaced a few screws/bolts here and there and a Valve Cover Gasket. I chopped the back of the frame off and remounted the fender, put new taillights, solo seat, all semi-gloss paint job. It looks totally sweet (pics to come)!

Last night I rode it around for the first time since last fall. Keep in mind it ran fine last year so I didn't really do any tuning or engine work. New foam filter but that's about it as far as performance. It ran great! And I was so happy to be finally riding again! I filled here up with gas and it started to rain so I covered it and reluctantly retired her for the night.

This morning I was going to ride to my buddy's machine shop to get the brackets for the new solo seat welded up. At this point the seat was just sitting on there, but I assure you the bolts on the bottom of it lined up with the frame as to not let it slide off or anything.

Here's where the problem began:

I noticed that around 4500 RPM it would kinda bog down. If I laid on the gas a little more it would smooth out. So I'm thinking "Crap, I guess I should rebuild the carbs." Almost to the shop and in a little bit of stop and go traffic, I slowed to a stop and noticed a moderate cloud of white smoke blow around me. I looked the bike over as much as I could on it and didn't see/smell anything but was worried it was coming from the bike. Get to the shop and park it. Fine. Really stoked to be riding!

So, I walk out to the bike after much showing off and lots of compliments.
Start it up and it's a little hard to start. It's cranking fine just not starting. Played with the choke a little bit and it starts. Immediately smell gas! Really bad! Look down and gas is pouring out from the bike onto the ground! Killed it with a quickness and find gas coming out of the airbox drain. Pulled the air filter and cranked it (after letting it cool down a bit) and see a solid stream of fuel shooting back into the box! Not good and already totally bummed! So I go inside to get more tools and get online and check XJBikes.com. Thinking it's a carb issue for sure; I go out to pull the carbs since I'm not gonna be riding it home. I notice that the "fuel" spot was still on the concrete and pretty wet with the sun shining full force down on it the whole time. Turns out it's not just fuel but a fuel/oil mixture. So I crank it over with the carbs removed and hear this horrible sloshing, pumping sound and the stream is still shooting into the airbox! How could this be? Well OIL was pumping out of the breather hose into the airbox!

I left it at the shop. I know it didn't have too much oil in it b/c I filled it yesterday with 5.5 pints ( 2.5 quarts) after the drain and filter. Besides it ran fine all the way there and the day before. Thinking back to the smoke I saw... did I narrowly escape a fiery death? Maybe it was leaking fuel through the carbs into the airbox when I was riding it? But then why was there no fuel on the ground when I came back out to start it, and only after I started it? Maybe it was filling the crankcase while I was riding it, and finally reached full up when I started it, then blowing it all back out? I don't know but I'm ready for some help or I'm parting it out!

 

5.5 Qts? Thats way too much oil for that bike. The oil level should be only up to the top line in the sight glass window on the RH side behind the clutch cover.

 

oops sorry i meant pints. I put less than 3 US quarts in it.

 

oops you posted correction.

If It's oil and gas could be needles still.

 

Carbs are flooding. One or more float needle(s) are stuck open. Give the bowls a solid whack with a wooden hammer handle and see if that doen't solve it (for now).

Of course, change the oil first! Before you ride it again! In fact, change it twice!

 

Well like I said at first it was just gas. I mean it was pouring out of the little tiny hole in the airbox. And it was pretty light colored like fuel. After I took the carbs off is when I noticed it was oil as well. I'll be going back to the shop first thing in the morning with the tool box (rubber mallet included) hopefully I can get her going!

Thanks Everyone!

 

i had mine do that ... stuck float needle will fill the cylindar with fuel ... it will leak down into the crank case filling it with fuel. when you start the engine it will run but when you rev it puts pressure and shoots the oil gas mix out through the crank case vent tube into the air box which has a drain hole to let you know when things go wrong.

Drain your oil / gas from the crank case, flush and re-fill while looking at your floats, needles etc.

 

The really bad part of this whole experience is you get REALLY paranoid about a possible reoccurance even once everything is fine and it causes you to check your oil before and after every ride.

For this to occur BOTH the petcock and the floats have to be passing fuel when they shouldn't. If all was indeed well last fall, then you probably need to install an inline fuel filter pronto. Crud can cause both floats and petcock to not shut off properly.

 

Mine did that, but it was due to me setting the floats incorrectly.

Same symptoms, oil/gas shooting into the airbox when I started it.

Gave me quite a scare.

 

Yup - I'm also in with the stuck float valve crowd -- pretty sure MidnightBlu nailed the description on that one.

Drail & refill, give the carbs some gentle but firm whacks with a wood handle, and schedule a cleaning & rebuild soon. Oh - and new plugs are likely in order too!

 

I ran into the same problem. Still paranoid as I check regularly for leaking gas.

I had a combination of things contributing to my problem. Sticky floats, incorrect float heights, and dried out float valves. Replaced the float valves, reset the float heights, and knock on wood, have been leak free so far.

 

So today I changed the oil twice. Put the carbs back on and installed a new inline fuel filter. Everything is great except now there is fuel kind of spraying out ( just a mist ) around the petcock whenever I give it throttle! So what do you guys think is better? Rebuilding, or replacing with the manual gravity feed one that chacal sells? I mean it would be nice to eliminate the possibility of leaking while in the run position and to have an actual "OFF" position. But I guess its only good if you remember to turn it "OFF!" Any experience with either?

 

My Norton has manual petcocks and IF the one time you forget is also the one time a float sticks... it has happened to me.

Sounds to me like you need to rebuild (or replace) your petcock.

If all the mating surfaces inside are clean and smooth, rebuilt petcocks can be perfectly reliable.

 

You pretty much forget to turn a manual petcock to the OFF (or the ON) position about once........and then you "learn to remember"!

 

I like the "set it and forget it" of the vacuum petcock, but I like the reliability of the "on/off" - So it comes down to what do I trust more my memory, or my petcock and in my case the petcock wins every single time :S
Like fitz said, a rebuilt petcock is perfectly reliable and no worry about memory lapses either

 

after you get the float situation settled, you are going to want to change your oil. The gas in your crankcase will dilute the oil and basically thin it out making for hard starting...someone should be along to better explain this in detail...but it isn't good to start it like that.