Runs then dies then runs

[huskerrob]

On my 85 fj1100 it seems to have a weird problem. The first time I ride it for the day it runs great no problem. However the next time it starts right up as normal but then as I am going it dies on me. so I sit there and open the gas cap (no clue if it helps) wait a minute and then it fires up and runs like normal. Any ideas on what that could be?

[Pat Conlon]

Lift up your tank and check your fuel line.....

A common problem on the gravity fed 1100's and 1200's is a pinched fuel line which will give the exact symptoms you are describing.
Proper fuel line routing is critical and you should have a picture on your air box or back fender, if not, let me describe:
As the single fuel line leaves the petcock, it should run *under* the 2 branch lines which feeds #1/2 and #3/4 carbs.
If the single fuel line is run over the 2 branch lines, the bike will start and run for awhile, then as the engine heats up the (now warm) fuel line gets soft and pinches, starving the carbs for gas.
So you stop.....wait for awhile, gas slowly flows thru the pinched line, refills the carbs and your bike will start again and run for a short while 'till it happens again.
Also, some folks have mistakenly installed a fuel filter on this gas line. A high flow screen filter is fine, but a paper filter will restrict the gas flow, even when new.
Paper filters are fine with a fuel pump pushing fuel through it, like the '89+ FJ's, but are a problem on the gravity fed "84-"87 bikes.

Hope this helps.   

[huskerrob]

well that is what I thought it might be, but I dont get why it never does it on the first ride of the day. And after it starts from dying it doesnt die again.

[Pat Conlon]

"....... then as I am going it dies on me....."

How does it die?  When it dies....does it seem like it's running out of gas, or is it a sudden shut down, like a ignition problem?

If it seems like it's running out of gas....and your fuel line is routed correctly......the next culprit to check is your vacuum petcock.
Engine vacuum keeps your petcock open and the gas flowing to your carbs, if you lose vacuum to the petcock, it will close, shutting off the gas. Check the vacuum line running from the petcock to the #4 intake to see that it's tight. When the bike dies, try lifting the tank and turning the petcock from ON...to prime (P) and see it that helps. Maybe you need a new petcock from RPM.

If the bike is shutting down electrically, check your sidestand shut off switch. Isolate (disable) the switch by disconnecting the connector and (on the engine side) jumping the wire connector's 2 prongs with a short piece of wire.
Check and clean your shut off rocker switch on your right handlebar. Check/clean your ignition switch, wiggle the key.

Don't give up.

[huskerrob]

It seems to be a gas issue not electrical. However it has not happened for a couple of days now, crossing my finger, maybe it has fixed its self.

[Arnie]

You're welcome to hope, :-) but realize that it is very rare that things fix themselves.
What is much more common is that after giving you fair warning, they hold together until you're somewhere without tools or shelter or help that they suddenly re-appear to stop all forward progress.
If you are lucky enough to get a warning - take advantage of it and spend the time and $ needed to find and fix the problem properly.
Just my opinion, but don't call me at 3AM to save your sorry self when you get stuck back of beyond. :-)

Arnie 

It seems to be a gas issue not electrical. However it has not happened for a couple of days now, crossing my finger, maybe it has fixed its self.

[huskerrob]

IT still has not happened. I was working today and I think I had my gas on reserve. We will see if it happens again. Thanks guys 

[Pat Conlon]

There is no reserve on the '85 FJ, only a red warning light. Best wishes.

[huskerrob]

There is no reserve on the '85 FJ, only a red warning light. Best wishes.

What does the "res"" mean on the petcock?

[FJmonkey]

There is no reserve on the '85 FJ, only a red warning light. Best wishes.

What does the "res"" mean on the petcock?

It means you have an after market or later year petcock.

[huskerrob]

Awesome! When I got this bike I didnt get much history on it, but it appears they took good care of her 

[huskerrob]

Ok I am completely lost. I cleaned my carbs out (which looked fine). The bike ran fine for 120 plus miles and the problem re-occurred. When I went to start it once, it sounded terrible. I tried riding it got a few blocks and it died all together. I have ran with the gas cap open, same thing. I took my coils to the local shop and they tested fine. At first I was sure it was gas related but now I have no idea. Could it be my Ignition box? Do the petcocks go bad? I am open to any ideas. Thanks guys

[fintip]

When you put the carbs back in, did you route the fuel line correctly?

When it was running poorly when you started it back up... Did you give the bowls enough time to fill up, or was it running like the bowls were not being well supplied?

If not, then how was it running poorly?

What color are your spark plugs?

[fj11.5]

Not sure if this is the same issue as ive just sorted on the 84 , , since the guy bought it 6 months ago its always sounded like its either  starving  for fuel or spark, had the carbs apart about a dozen times, replaced  pilot jets, cleaned , blown air through,  changed fuel lines ect ect,,, plugs Looked ok,  just sooty from so much  idling trying to sort it, but today after bolting the carbs back in i thought after once again she wasnt running  right still,  shifted the synch gauges and threw 4 new plugs in, low and behold she now idles smooth, revs cleanly just some fine tuning after a ride needed and its the best its ran,  he had it for 6 months wouldnt ever idle properly