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General Category => Yamaha FJ1100 / FJ1200 Running Problems => Topic started by: 89fj on June 22, 2014, 12:23:47 AM

Title: Carb or timing?
Post by: 89fj on June 22, 2014, 12:23:47 AM
I had gotten my old fj 1200 89 from the guy who bought it from me rode the crap out of it and then thought the starter was messed up and stuck it in a shed for 10 years. So I got it back and went through everything and got it back up to shape. I went through the carbs and replaced / cleaned the jets. It has a Dana 2000 ignition. Acell coils and 8.8 wires. It is running open Venturi style carbs. (I know I need to get pod air cleaners but I am dreading the rejet process. I had the valves checked and fixed. Dropped the sprocket sizes back to stock. Ect. Ran good but when I got to 4.5 k rpm it would stall almost like hitting a rev limiter.  Buy if I clutched past it to 6k it would take off like a rocket. So I thought raise the needles a notch or two. This helped a bit but made it stumble slightly through the same range but it would push through eventually. (This was today at about 95 degrees outside) on my ride home it would run ok up to 4k but then not make it up over worth a crap under load. It would rev fine if I pulled in the clutch. I am kinda lost on the ignition timing set up. Any advice?

Thank you,

Lucas
Title: Re: Carb or timing?
Post by: 89fj on June 22, 2014, 12:51:10 AM
Dyna ignition sorry for the misspelling.
Title: Re: Carb or timing?
Post by: fj1289 on June 22, 2014, 01:54:58 PM
I'd go ahead and install air cleaners - won't change the jetting that much and it's better to sort it all out as you intend to ride it.

Check all the basics first - set up the Dyna per the directions (available online if needed). Forgot the settings that work well with the stock engine, but nothing should be totally out of the ball park.   Clean the carbs.   Clean the carbs.   Clean the carbs.   Then you're ready to clean the carbs again.  Check for problems like cracked slide diaphragms.   Also expect to have worn out (oval) emulsion tubes.  Those will make a good jetting setup almost impossible.   

Good luck and keep us posted on your progress
Title: Re: Carb or timing?
Post by: 89fj on June 22, 2014, 03:06:39 PM
I am going through the ignition set up again now. I have cleaned the carb well but you may be right about the emulsion tubes. I haven't replaced them yet. I will keep working and keep this up to date with the progress.
Title: Re: Carb or timing?
Post by: fredsone on June 24, 2014, 07:10:54 AM
Back in the day I would sometimes have a problem similar to this.
When I went on the motorway (and tried to have some fun with car etc) the bike would get to somewhere between 4-5k and then just wouldn't pull. Even going down a gear didn't help (it really was like hitting a rev limiter).
I realized it only happened when the bikes (I had 3,1x1100 and 2x1200) had done lot of slow inner city commuting.
I found that what solved the problem was pushing the revs up as high as possible (4-5k) and waiting for the motor to clear itself (it generally took less than a minute), an event usually accompanied by a bit of coughing (a bit like a misfire) then it would clear the crap out and be away and all would be fine until the next heavy commuting period.  

I figured the issue was simply the motor couldn't breathe because it was clogged with mung from lots of running at low revs, is it possible that was the issue?
Title: Re: Carb or timing?
Post by: theLeopard on June 25, 2014, 03:14:49 PM
Quote from: Mark Olson on June 13, 2014, 02:36:01 PMYOU MUST : ride your fj like it is a high performance sports car .  Meaning if you baby it and don't rev it up and floor it (pin it ) it will LOAD UP and run like shit.

most of my city driving is done in 3rd with constant 'celeration.
course I live in Cali so I can shoot the gap, makes life more interesting anyway :drinks: