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Running issues after acceleration

Started by Lofty1990, February 17, 2022, 04:43:27 PM

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Does anyone know why my fj1200abs 1991 runs rough and dies after acceleration

Fuel
1 (33.3%)
Carbs
2 (66.7%)

Total Members Voted: 3

Lofty1990

Hi guys/ladies...... took my fj out today as it was a lovely day for a morning ride, I thought I would get myself on a nice open road and blow the cobwebs out... sure enough that's exactly what I did- however!  The second I got to the roundabout the engine spluttered like I'd blown it up then died, thought it was a big problem, but after pulling the choke up and finally getting it to run again it sounded like a bag of spanner's until it cleared and went back to normal???  Anyone else had this or any ideas of what could have caused it??
Many thanks in advance Carl..
If it ain't an FJ it ain't worth riding!!

FJmonkey

The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

Lofty1990

Truth be told the bike had done 8k miles in the past 20years, it runs fantastic 99.9% of the time, idles lovely goes through rev range nicely but the second you open it up hard it's like it's not getting enough fuel, sounds rough then dies
If it ain't an FJ it ain't worth riding!!

Sparky84

Quote from: Lofty1990 on February 18, 2022, 02:50:27 AM
Truth be told the bike had done 8k miles in the past 20years, it runs fantastic 99.9% of the time, idles lovely goes through rev range nicely but the second you open it up hard it's like it's not getting enough fuel, sounds rough then dies

Sounds like you're right with the fuel, possibly crap in your carbs with only 8k for 20yrs, too much sitting around maybe.
1984 FJ1100
1979 Kawasaki Z1300
1972 Honda CB750/4 K2

jono

try bypassing the fuel sender i had a problem with my 91 after hard acceleration it would run like shit for a while so after asking the guys here and re jetting etc it still did it .then i read about the fuel sender which bought back memories of my old fz750 which used to cut out completely and so we wired the pump straight to power and no more problems so i did the same thing to my fj and no more problem but after a couple of thousand km my rev counter gave up so Ive gone back to running a sender unit again ,so you could try running your pump directly from power to see if it is the sender but i would recommend replacing the sender unit if it does fix the problem and not leave the fuel pump hot wired indefinitely

jono
1991 fj1200

Dads_FJ

Maybe the tank isn't venting.  Easy test - ride it with the cap unlatched.
John S.

'84 Yamaha FJ1100
'89 Yamaha FJ1200
'94 Yamaha WR250
'80 BMW R100S/Sidecar
'39 BSA WM20

fj1289

While we are all throwing out WAGS (wild assed guesses) at what we cannot see, feel, or hear, mine is carb slides sticking.  Especially with the history of sporadic use and relatively sporadic symptoms. 

Lofty1990

Really appreciate the input guys I'm off tomorrow so going to have a little play with her and see if any of this things you have mentioned help, I'll give an update tomorrow afternoon thanks so much
If it ain't an FJ it ain't worth riding!!

fj1289

Most suggestions are fairly easy and straightforward to try so you should be able to get through most of them!

fj1289


Lofty1990

Hey guys, sorry it took me a while to get back in here, weather been not so good!
So what I did was popped in a few new plugs and filled tank up with premium unleaded and gave it a good 100 mile run..... all seems ok at the moment I'm starting to think maybe it was a bit of nastiness from bottom of tank maybe, I'll be giving it another few runs hopefully this week and I'll update again... really appreciate all of your comments, you've really helped me.... Thank you so much
If it ain't an FJ it ain't worth riding!!