Ran fine, but now....

Hi everyone

Mostly a lurker, but now that I have an XJ again, I'll probably be more active here.

Bought an 83 XJ750 Maxim from a friend

Was stored properly (other than the front tire sitting directly on the floor) for about 5 years in a sea can

Bike fired up and ran perfectly after draining the old gas out of the tank, putting some fresh gas in, and installing a brand new AGM type battery

Fuel Tank is very clean on the inside, very very little rust, MUCH less than you would expect for a 39 yr old tank. Just a tiny bit of "flash" rust.

Bike has an external fuel filter

Bike ran perfectly

Took it for a spin around the block, ran perfectly, shifted fine, handles fine

Rode it across town to get it to the shop for its provincial safety inspection, and it ran perfectly. It wanted to go and I really had to restrain myself, lol
Emgine was gone theu by a reputable shop the last season it was ridden. Clutch assembly was rebuilt the year before.

So, it only needs a front tire (sidewall is dried and cracked where it was in contact with the ground for 5 yrs) and the safety switch on the clutch lever assembly (physically broken) in order to pass the inspection

Go to bring the bike home from the shop last night to do the work over the weekend

Bike wouldn't start properly, and when it would try to start, it was only running on the two lefthand cylinders. Both right hand exhaust pipes were cold whilenm the left two were warm

Bike was parked at the shop on the side stand since dropped off there, petcock was in it's normal position while parked

It started and ran fine the day following the night I dropped it off as well, as they thought there was a clutch issue (they didnt know about the safety for the side stand and it was stalling on them when they'd put it in gear with the stand down)

Before I start ripping into the carb rack, I just wanted some additional input to see if I'm on the proper course here, as I'm thinking fuel issues, hopefully simple float valve issues or other blockages in the two rh carbs

I Dont think its a spark issue, as it's two cylinders on one side affected, not one on each side

Any input would be appreciated

TIA

Travis
aka Short Circutz

 

If it ran fine the LAST thing you want to do is tear into the carbs!! Check EVERYTHING ELSE FIRST.

 

Before you do any work on the carburettors check the valve clearances first even though it ran fine. Wasted spark system so cannot be a pick up coil or ignition coil or TCI. Did it need choke from cold? If the small jets on the two right hand float bowls are blocked that could be the problem.

On a cold engine you could spray engine start into the air filter intake and see if the four cylinders run. If so definitely a fueling issue. Clean the spark plugs on two dead cylinders in case they are fouled. What do the spark plugs electrodes look like?

 

I feel like a dumbass

Bike is fine

It was parked with petcocknin Pri position and I guess I have an issue with one of the carbs having a float needle not seating properly

It was just simply out of gas!

Got the bike home earlier today just fine!

#imadumbass lol

 

We have all been there lol

 

So make sure you change the oil, that gas had to go someplace. I would guess it is all mixed with your oil. Please don't run the bike that way, your bike will not like that.

Take a look at the oil level window, if it is full check the oil by smelling oil fill hole, if it smells of gas, pls change it. Your bike will thank you for it.