Bike shut down

[DCW]

I know this was just talked about but here is what happened to me.  Had been riding my 86 most of the 90 degree day and it had been running great.  All off a sudden started losing power like it was running out of fuel.  Light wasn't on,  it does work,  switched to reserve still nothing.  Got off the road and checked my gas and I could see fuel above the tank divider so I had plenty.  Tried to start several times and nothing.  After sitting 30 to 45 min.  it fired right up.  No choke not even a sputter. Rode it home another 45 min. and it never missed a beat. Didn't have a tank bag on this time.   Don't know if the cap has been done like you guys are talking about or not.  Can I tell by looking at it?    I was thinking electrical, something getting hot and cooling off, Now I wondering about this vent.      I just bought the bike this spring and it has about 10k on it and this was the longest ride I've taken on it. Don't know if it has ever had this problem before or not.    Tell what you think. 

[Dan Filetti]

If you tried to start the bike after opening the cap, and it still did not fire up, and it sounds like that is the sequence you underwent, then it's not the flap.  The flap fails to vent the tank properly so a vacuum condition builds up in the tank which eventually results in fuel starvation.  Opening the cap equalizes the pressure, so it should fire right up after that.  Or at least a few seconds later, after the float bowls are filled back up.

Check the vacuum line to the petcock (I think the '86 still had this) for cracks or wear, loss of vacuum there could close the petcock and give you your symptoms.

Also, if you've had your tank off recently, check carefully, the fuel line routing, it's very sensitive to improper routing.

Keep at it, you'll figure it out.

Dan 

[FJmonkey]

FLAPECTOMY!!!! Just do it.

Is this the third one? I hope they only come in threes........I am so done with the flap....

No ill wishes DCW, thank you for asking the question. It seams like it is hailing tank vacuum issues from the ill fated flaps. Klavdy did a nice rite up with his toads on how to remove the flaps. If you choose to accept this mission them get a bucket or large plastic bag to work in. A gnat size ball bearing will fall, or shoot out. Don't loose it!!! Members have lost vision, have oily discharge (not the bike), and decided they enjoy being audited by the IRS. You were warned...

[FJmonkey]

Or what Dan said.....

[Kopfjaeger]

 

[DCW]

Ok,  sorry I brought up the flap again.   If this was a vacuum line would it start and run again.  No I havent had the tank off .  Now I'm back to thinking electrical.  Since we known it not the FLAP.  Darn, I brought it up again   Thanks guys for the help

[FJmonkey]

Ok,  sorry I brought up the flap again.   If this was a vacuum line would it start and run again.  No I havent had the tank off .  Now I'm back to thinking electrical.  Since we known it not the FLAP.  Darn, I brought it up again   Thanks guys for the help

DCW, FWIW, I did not intend to intimidate you for posting. I encourage all to post and ask questions (for some a quick search would really help before posting). I was venting as it seemed like the world was having an epidemic of Flapper issues. I had my rant at your expense and hope to really help you solve your issues. I am really better as an introvert and hiding in the shadows, solving engineering/mechanical type issues. It really does seem like the fuel starvation issues I had when running at 75+ on my 400+ mile runs. It got worse when the tank bag pad got wet from the rain, it sealed the fuel cap and made the flappers seem like a small problem. It really sucks to be on the side of the road in the rain when you have over 350 miles to before you can see your kids. Hugs and Teddy bears right? 

[TRoy]

OK, opening the gas cap is NOT an instant fix.. the carbs don't refill as fast as you think. I've been here dozens of times (back in the day)

...even after filling the tank, it may sometimes take a couple minutes (with the engine RUNNING) for things to get back to normal.

remember on 87 and older FJ's the engine has to be running for the petcock to open. it operates off vacuum.

take out the fucking flap(s), go ahead and take the cap assy apart further and make sure the vent system is not plugged like mine was.

not only are there flaps, there are also little ports & channels going to and from these flaps, make sure they are clear