800 mile round-trip; had fuel line/ carb problems

Ok,
My bike is an 85 XJ 700, 13k miles, and this past weekend I took it for a hard ride on mountain roads with lots of switchbacks.. About 150 miles into the ride it started to run like shit and died on the side of the road.. After about 30 mins it started back up but still ran shitty so I pulled over again and let it sit for a while.. I fired it back up and made it to the next gas station and it started to run good when I left.. So I pressed on for another 60 miles till it did that BS again, so I pulled over and took the tank off.. I noticed the small vacuum line from the petcock had a pinhole in it near the #2 carb, so I cut it off and pushed it down further onto the nipple.. The bike ran fine for another 500 or so miles until it began doing the same thing on the way home.. I stopped in a town and got some 5/16" fuel line from oriley's, and I found some zip ties on the ground in the parking lot that I used for hose clamps. The 5/16" fuel line is a little loose on The petcock and nipple on the #2 carb, so I had to cinch it down as best and cheap as I could (adventure motorcycling on a budget lol). The bike fired right up and ran fine for another 80 miles but started acting doggy again and like it was flooding.. I could roll on the throttle and it had no power, but the bike seemed like it was jerking and revving with the throttle in a fixed position.. If I pulled the clutch in it with the throttle open it would rev up, if I let the clutch out it would bog down and loose power. I pulled over (again) and put the petcock on prime. I could see a tiny drizzle coming through the inline filter, and then it would taper off to nothing.. After that I took the main fuel line off of the petcock with the prime on and gas flowed out freely. Confused, I hooked it all back up, choked it and started it up.. The bike ran at a low idle for a few minutes, if I took it off choke it would die. The idle increased after a while, but the engine seemed out of time and wanting to backfire... Finally, the bike backfired and the rmp's shot up and the motor smoothed out.. The bike ran fine the rest of the way home.. Today, I took it to the grocery store and it started in with that same BS again-- the loss of power and whatnot... Any help or suggestions would be appreciated...

 

Here is a picture of one of the few stops I made while wondering if I was gonna make it home..

 

Is your gas tank cap not allowing air in may cause that problem of fuel starving
There is a little check ball in the cap that can get gummed up.

 

oops pushed the button twice

 

• Ill check that out in the morning... I know I've topped it off before and gas leaked out from the cap when I made a hard right turn... I think it may need a carb sync / cleaning.. Just had that done in December though and I've put 3000 miles on the bike since then...

 

This. This is your smoking gun. Going by what you wrote there, there is a clog in your line between the petcock and the carbs. Replace the filter, plus it's a pretty short piece of fuel line- can you blow/see light through it? If fuel flows freely at prime, did you try running it on prime?

 

have you put the proper vacuum line in the bike yet? use clamps not zip ties.
test your petcock, put on run and apply vacuum to the vac nipple does fuel flow?
the clean or replace the in line filter.
could be you got a dirty intank filter on the petcock.
make sure all fuel clamps are tight could be sucking air

clean air filter

do your carbs have filter screens on the needle valve bodys?

with all the switch backs you could have knocked any tank crud loose

rebuilding the gas cap
Your Gas Cap and You

ohm out your ignition system and then when it runs poorly ohm it on the side of the road

 

Another suggestion...if you still have this problem...go for a ride, when the bike start to acting, stop and check the mufflers just from the carbs and check which one is hot and wich one is cold. If you find a cold one, take the spark plug off and check it for signs of overheat or oil, or too much gas. Any way replace it. If that solves the problem, is not so easy, you have a valve clearence problem, have that check.

 

So, I replaced the vacuum line on the petcock with the correct size line and it fixed the problem.. Actually, Im not exactly sure if its the right type of vacuum hose but I used windshield wiper vacuum line from NAPA.. also changed my fuel filter and cleaned my air filter as best I could (sprayed it out with carb cleaner and hit it with an air compressor).. I had to choke it and mess with the on/reserve/prime to get it back to normal... even the tiniest air leak and these bikes wont act right..

 

Imo buy a length of oe vac line from Len. That vac line might collapse due to heat over a period of time.


Gary H.

 

I'm glad you made it home. There's only two things I can think of that we don't attend to until "it happens"...the starter chain guide (if equipped) and the starter clutch. Everything else is pretty much accessible. I'd make certain all the scheduled maintenance items are in good nick prior to riding those kinda distances.

Gary H.

 

Vac line is Vac line. What you got has the wall thickness for the job.

 

It is depending on what it's being used for.

Gary H.

 

The old one that was on there must have been stock; it was Sun-beat and much "floppier" than the replacement.. I'm sure that there are some more hoses and such that I should replace as well...
I think it is certainly an improvement though, the bike runs like a champ.. Sometimes it's hard for me to believe that my bike is 31 years old!!