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General Category => Yamaha FJ1100 / FJ1200 Running Problems => Topic started by: ForgottenFJ on July 10, 2012, 02:30:41 PM

Title: Runs with Choke but dies without it.
Post by: ForgottenFJ on July 10, 2012, 02:30:41 PM
I am trying to get my 1986 FJ1200 back together and running after being off the road for 16 years, I took the carbs off and had a Tech here at work go through them.  He completely disassembled them and cleaned everything, I put them on and it will start with the choke but as soon as I shut off the choke it sputters and dies.  I took the carbs back off and checked the connectors, they look great they are still very pliable and have no cracks in them, I made sure the carbs were seated correctly and even used dielectric grease to help seal them, but I still have the same issue. I turned the idle screw on the bottom of the rack all the way in, but still no change. I try to rev it up with the throttle and it spits and sputters, I have no clue what to try next, I was so mad Saturday that I about pushed it out beside the road with a free sign on it.  I started this as a way to try to relax but find more aggravation than relaxation, I guess I will stick with cars at least I understand them (well the old ones anyway) all help appreciated, Thanks  :dash2: :dash2: :dash2: :dash2:
Title: Re: Runs with Choke but dies without it.
Post by: SlowOldGuy on July 10, 2012, 02:35:01 PM
Assuming everything is installed correctly and there's no huge vacuum leak, then it sounds to me like your "Tech" did not get the idle circuit clean.  Very small jets and passages in the idle circuit are easily clogged and sometimes hard to get totally clean. 

Ask him if he removed the idle mixture screws.

DavidR.
Title: Re: Runs with Choke but dies without it.
Post by: andyb on July 10, 2012, 03:45:21 PM
Ayup.  Pilots are pluggered up!

The pilot jets need cleaned, the mix screws need pulled, and the passage between the two needs cleaned.  Assuming nothing major is screwy, that'll sort it.
Title: Re: Runs with Choke but dies without it.
Post by: yamaha fj rider on July 10, 2012, 07:39:35 PM
Andy and David called it right sounds like it needs to go back to your tech for some more cleaning. Sorry for the bad news.  :sorry:

Kurt
Title: Re: Runs with Choke but dies without it.
Post by: RichBaker on July 10, 2012, 08:51:24 PM
Yep... classic symptoms of a clogged pilot/mixture circuit.......
Title: Re: Runs with Choke but dies without it.
Post by: andyb on July 10, 2012, 11:30:33 PM
Well, before blaming the guy who did the cleaning... if you run gas that's full of particulate crap, it'll do this almost immediately to even the cleanest of carbs.

Title: Re: Runs with Choke but dies without it.
Post by: yamaha fj rider on July 10, 2012, 11:59:59 PM
Andy true after sitting that long could have junk in the tank. But either way it will need to be cleaned again.  (popcorn)

Kurt
Title: Re: Runs with Choke but dies without it.
Post by: ForgottenFJ on July 11, 2012, 09:57:12 AM
I don't have the tank on it yet, I have been using a gas bottle hooked to the hose, and the carbs were completely disassembled and cleaned out, all the screws were removed and the passages cleaned. I looked over everything when he had them apart, he left nothing together. I will be taking them back off to have him recheck them anyway. Thanks for all the Help.  :good: :good: :good: :good:
Title: Re: Runs with Choke but dies without it.
Post by: racerrad8 on July 11, 2012, 10:07:05 AM
Make sure he took out the pilot jets...

They are down in the well behind the main jet and look like this; Pilot Jet (http://www.rpmracingca.com/proddetail.asp?prod=Carb%3APilotjet)

Randy - RPM
Title: Re: Runs with Choke but dies without it.
Post by: Derek Young on July 12, 2012, 08:41:28 AM
With carbs there's clean then there's CLEAN! You need the latter. Also, when running without the tank on, make sure to plug the vacuum line that goes to the petcock.

Derek
Title: Re: Runs with Choke but dies without it.
Post by: ForgottenFJ on September 08, 2012, 11:03:13 PM
Well after a very long delay in getting my carbs back, Yes there was junk in the idle circuit like was suggested by many on here. I installed them this morning and it fired right up and purred like a kitten, it was an amazing feeling to see it sitting running after so long, it will need a good sync, but it lives.  I was excited to actually sit on it and feel it move by its own power as I pulled it back in the shed, it hasn't moved on its own since 1996.  My daughter especially loved the part when I throttled it up to pull up over the ledge in front of the door and it spit dirt off the back wheel, it kind of reminded me of the old dirt bike days.  Next project is to get the tank put back on and I need to do some repairs on my upper fairing and of course the reassembly of everything else, it needs a new mirror and maybe a side vent, not to sure mine can be fixed, but at least it runs again. Its been this long I don't think a few more weeks will make much difference, well thanks for all the help I am sure I will need more as this project progresses. :good: :good: :good: :good:
Title: Re: Runs with Choke but dies without it.
Post by: FJmonkey on September 08, 2012, 11:10:12 PM
It is alive!!!! Good to hear, any life brought back is grounds for Kookaloo like celebration. Now get some miles on the beast and some smiles on your face..... 
Title: Re: Runs with Choke but dies without it.
Post by: yamaha fj rider on September 09, 2012, 09:18:52 AM
Congrats on getting it running again. Check out the files section for mirror upgrade cheaper than stock. Keep us posted.  :yahoo:

Kurt
Title: Re: Runs with Choke but dies without it.
Post by: ForgottenFJ on September 11, 2012, 03:52:30 PM
I am curious I found some pieces of what looked like plastic under the bike after it was running, I found some in the shed too. The pieces are kind of reddish brown and are flat and looked like they used to be circular, I don't remember anything that looked like that when I had it apart.  I thought about exhaust gaskets but never seen gaskets that were plastic like that in an exhaust system, I will have to take apart the pipes to see if that's where they came from... :dash2: :dash2: :dash2: :dash2:
Title: Re: Runs with Choke but dies without it.
Post by: yamaha fj rider on September 12, 2012, 08:26:25 AM
Quote from: ForgottenFJ on September 11, 2012, 03:52:30 PM
I am curious I found some pieces of what looked like plastic under the bike after it was running, I found some in the shed too. The pieces are kind of reddish brown and are flat and looked like they used to be circular, I don't remember anything that looked like that when I had it apart.  I thought about exhaust gaskets but never seen gaskets that were plastic like that in an exhaust system, I will have to take apart the pipes to see if that's where they came from... :dash2: :dash2: :dash2: :dash2:
Send some pictures if you can. Hope this helps.

Kurt