Dies after 80 miles or so...

Here is one for you guys. Mine is an '82 xj650j (Maxim) in my first season with it. Earlier this year I took it on a long-ish ride, and at about 80-90 miles is started to run very roughly, and within 1/10th of a mile she died. After it rested 3 - 4 minutes, I could bring it back to a weak, very poor running, very under-powered life for a minute or so before she died again.

I had the carbs redone and balanced by a very reputable mechanic. The compression checks fine, and I replaced the plugs (with NGK). It seemed to run pretty well again.

Today, I took it out for its very next long-ish ride, and wouldn't you know, the same thing happened at 80 or 90 miles.

I am running 89 octane unleaded fuel with a touch of sea foam.

Thoughts?

 

This is silly ... but, -- What's the range on a 650's fuel tank. You don't say anything about the possibility of FUEL STARVATION.

And ... take a close look at your Petcock Vacuum hose. If the hose isn't vacuum hose -- (I've seen some guys swap the Black vacuum hose for the clear, new, vinyl hose that comes with a new battery) -- when the hose gets heated-up just right ... the engine's vacuum causes the hose to collapse on itself ... cutting-off vacuum to the Petcock ... which shuts-off the fuel supply causing the bike to lose power and die.

 

Thinking along Ric's lines myself. Keep an eye out for the 79 mile Gas station.

My 550 with a slightly smaller tank than the 650 will get around 100 miles before reserve. Also look for kinks or raised fuel lines. My 1100 has the fuel line going from the taps up and over the airbox rubbers before going down to the carbs. This means it starts running a bit rough when the tank is getting low due to not enough "head" pressure to feed the carbs over the bump.


Just fill her up every 70 miles and ride, ride, ride.........

 

My 81 650 had a range of about 90 miles too.

 

You might want to check the charging system. If it's not providing enough current, you may be running on battery power until the battery's reserve drops below the point where the ignition system will function. The short run time after a wait may be the battery recovering a bit of its charge.

 

BINGO ...

Another victim of alternator brushes beyond the service limit???

 

Could be... or a faulty rectifier/regulator.

 

Great. I have a few places to start.

It seems to have fuel still sloshing in the tank, and I tried to switch it to reserve and it would not start there either.

After sitting a few hours last night, I had to let it crank for a bit and then it started and seemed to run fine. It does seem like maybe the fuel got cut off, but I will definately look into the electrical issues as well.

Meanwhile, I will be refueling every 60 miles or so.

Thanks again for your help.

 

see if it will run on prime. just don't leave it like that unattended.

 

I was having trouble with my bike when I first got it.turns out the main glass fuse had a break in the holder area.I changed em to a newer style and no more problem.

 

also try checking the screen on your petcock to see if it has crud built up on it on the lower portion???!
Who Knows, but the suggestions given sure look like good places to start!
Good Luck