Xj550 dies after a few minutes

My 83 maxim 550 will start but as it warms up the idle will race up high and then after a few minutes of that the throttle goes "spongey" and the bike putters out. Then it won't start back up for an hour or so. The carbs were recently cleaned well and tuned. The valves are in spec. Does anyone have any ideas?

 

Had a similar issue a couple years ago. What setting is your petcock on? Mine needed a full rebuild... PRI would sometimes work, sometimes not, ON worked, but it only trickled gas... enough to make it around the block. RES worked fine.

 

I replaced my petcock with a manual one about a year ago. When I pull the tank off and open up te petcock it flows out fine in the on position and the reserve position and shuts off fine in off.

 

pull the spark plugs and see what they look like. if they are black, you have a flooding issue. if they are white, you are not getting enough fuel. you may also want to check the plug wires and ends for shorting to ground.

FU

 

Did this develop immediately after doing the carbs? Could also be an issue with float heights or needles. When it dies out, crack the bowl drain screws, bet they are dry

 

Check for the smell of unburnt gas at the exhaust. A overly rich condition worsens as the bike warms up, causing it to sputter and die. Sounds like the idle might be racing to use up that excess gas until it finally floods. Could be a float pin leak, a stuck enrichment circuit plunger, or something else but it sounds like a fuel issue. One issue with manual stopcocks is they don't prevent gas from leaking by a bad float pin if they are left on after the bike is shut down. If gas runs out of the carb or airbox if you leave the stopcock open, you have a bad float pin or seat.

 

open the gas cap when it starts sputtering out

 

It was running perfectly for about 2 months after the carb clean. Then suddenly one morning it was hard to start and died when I got about 2 miles down the road. I just ran it again and couldn't get it to die but the idle was up high. I'll check the plugs.

 

Also check your fuel line for bends, soft spots, internal collapse

 

Fuel line looks good

 

I did (roughly 3 weeks ago) accidentally flood the carbs by leaving the petcock on and leaving for a hike. But after just waiting about half an hour it started back up and ran fine up until about 3 days ago.

 

I guess the other thing that is going on is I know the clutch is totally shot. I'm going to replace the plates but could the clutch have anything to do with this? Please forgive my ignorance. Haha

 

Have you checked the valves shim clearance?

 

Possible failed petcock diaphram. Fuel is being sucked through the diaphram, through the vac hose and into the head. That's why the petcock works proper when it's not running. Imo rebuild the petcock and gas cap, replace or add a filter and replace the fuel and vac line if you haven't already.

Gary H.