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General Category => Yamaha FJ1100 / FJ1200 Running Problems => Topic started by: stroscoach on May 06, 2011, 07:37:39 PM

Title: gas tank venting
Post by: stroscoach on May 06, 2011, 07:37:39 PM
Hi everyone , I know there has been a lot of talk on gascap venting , BUT I would like to ask a couple questions before I take my cap apart again. 1. My 86 fj 1200 runs great until a stop for  15 or 20 min starts right up and as I'm riding feels like its running out of fuel and engine quits I have tried opening the cap and restarting but the only way it will restart is if I set the petcock to prime. Does this sound like a venting problem 2. If so when I take the cap apart do I take the whole valve out or just the orange rubber pieces (the Toads weren't specific enough ) Thanks  In advance
Title: Re: gas tank venting
Post by: FJmonkey on May 06, 2011, 07:51:20 PM
Prime??? Not a stock petcock. Remove the orange flapper valves, or cut them off. Once gone the tank vents freely. This is also the case if the bike is on its side. The reason for venting the fuel cap with flappers and not just leaving a hole. Normal riding does not apply as fuel is kept in the lower position of the fuel tank by Centrifugal force.

If choosing to disassemble the fuel cap, search this site for all references to same. There is a very small ball that will shoot out and be lost forever. Line a bucket with a towel and take the cap apart in the bottom of the bucket. I just serviced mine and still have flappers, my FJ sings to me after a ride. And no fuel starvation issues.
Title: Re: gas tank venting
Post by: stroscoach on May 06, 2011, 08:04:42 PM
I took apart the cap following the steps in Andy b troubleshooting , The ball is already missing I just wasn't sure if I should just take out the rubber parts and leave the plastic piece so I just put it back together . Thanks for the info. Interesting on the petcock also
Title: Re: gas tank venting
Post by: FJmonkey on May 06, 2011, 09:24:44 PM
Quote from: stroscoach on May 06, 2011, 08:04:42 PM
I took apart the cap following the steps in Andy b troubleshooting , The ball is already missing I just wasn't sure if I should just take out the rubber parts and leave the plastic piece so I just put it back together . Thanks for the info. Interesting on the petcock also
Maybe you could just drill a hole in the top of the tank near the cap???? that seems like a bad idea, never mind..... let us know if your fix worked for you.
Title: Re: gas tank venting
Post by: Firehawk068 on May 07, 2011, 01:01:09 AM
Quote from: stroscoach on May 06, 2011, 08:04:42 PM
I took apart the cap following the steps in Andy b troubleshooting , The ball is already missing I just wasn't sure if I should just take out the rubber parts and leave the plastic piece so I just put it back together . Thanks for the info. Interesting on the petcock also

Mine used to push fuel up through the key-hole if it got warm with a full tank........was worse if I had my tank bag on.

I removed just the orange rubber parts, and put it all back together with the plastic holder back in place.
It no longer pushes fuel out of the key-hole, with or without the tank bag. :good2:
Title: Re: gas tank venting
Post by: andyb on May 07, 2011, 04:23:28 AM
Read this (http://www.fjowners.com/index.php?topic=2024.0) also, yes?

Title: Re: gas tank venting
Post by: stroscoach on May 07, 2011, 07:31:13 AM
Quote from: andyb on May 07, 2011, 04:23:28 AM
Read this (http://www.fjowners.com/index.php?topic=2024.0) also, yes?


Thanks Andy this was the pdf I used to take it apart the first time nice work putting that up ,Do you think this valve is causing my problems I got this bike from a guy who gave up trying to fix this problem.