FJ 1200 rebuilt carbs.. works for a few miles then stops...

[BristolFJ1200...]

anyone able to help me get my fj running?

I rebuilt the carbs and it ran perfectly... i go out for about 4 miles and then its craps out.. wont pull.

I have rebuilt them 3 times. Each time same thing.. runs fine then no good.

its not a temp issue as after the first drive its just the same. I thought it was the float levels in the carbs but i adjusted them and still the same issue?

tearing my hair out here.. .any suggestions?
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FJ1200 3CV

[nowhere.elysium]

Flush the tank a few times and try an inline fuel filter. Bear in mind that said filters often have a preferred direction of flow.
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'10 SV650SF, '83 GS650GT (it lives!), Questionable DIY dash project, 3D Printer project, Lasercutter project

[jaffa90]

What happens when it CRAPS OUT?
What happens when you give it choke after throttle off?
Does it have a fuel pump and is the tank breathing?
It`s a pity you can`t remove a spark plug due to fairings / tank.

[BristolFJ1200...]

yeah so i put fresh petrol in, new filter and new set of coils and plugs.. plus the local motorbike garage said it was too old for them to work on
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FJ1200 3CV

[BristolFJ1200...]

so choke makes it worse.. makes me think its running to rich but i dont know why. i might pull carbs one more time to check float levels and see what the plugs look like.. any home mechanics want to come take a look? any one that gets it going can borrow her anytime!
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FJ1200 3CV

[WD Forte]

[BristolFJ1200...]

yeah im in Bristol.. BS4 and about a bricks throw from Fowlups. Its paining me but they might get all my biscuit money if I dont solve this msyelf!
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FJ1200 3CV

[Evil Hans]

There's a reasonably priced FJ specialist up in Cromhall, just north of Bristol.

https://www.fjclub.co.uk/fj-motorcycles/4546500522
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Triumph Sprint ST 1050. And it's Red.

[sickpup]

Why did you rebuild the carbs?

[Nobby the Bastard]

Have you considered the coils?
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[Andy_Pagin]

Fuel pump? I've lost count of the number of times I've rebuilt component A only for component B to miraculously fail just afterwards.
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Yamaha Vity -> YBR125 -> FZS600 Fazer -> FZ1-S Fazer

[Fizzer Thou]

[BristolFJ1200...]

This poor running happened out of the blue.. i bought it and after about 50 miles it started running badly (on three cyclinders). I cleaned main jets and replaced the idle jets. After that it ran perfectly for another 5 miles.. now same problem.

the pump works fine.. ticks away happily and their is no vacuum from the tank.

it seems like its running really rich but i havent touched the mixture scres so cant see why that would change!

im tempted to swop the carbs for some known good ones
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FJ1200 3CV

[andym]

After you stripped the carbs you, did balance them again afterwards didn't you?

I recently had a problem with my fuel pump, where it would run fine for a bit then run like shit, I replaced the pump with a cheap one and it still ran like shit.... replaced the contacts in the old pump and the problem was sorted

[temeluchus]

https://www.fjclub.co.uk

Not far from Bristol and what they don't know about FJ's isn't worth knowing.

I'm thinking perhaps you've kinked a hose or something like that. Pop out a plug and have a look.
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Some shite cruiser. Now with guns and FREEDOM!

[Evil Hans]

[chris-red]

Trying opening the fuel tank cap when it runs crap, it could be as simple as a blocked breather.

After that Find what cylinder is cutting out, ~£10 temp gun aimed at the headers should do it, then switch the coils around and see if that changes which one is dying.
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WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

[BristolFJ1200...]

Well I left this awhile out of frustration but its pointless having a pile of steel outside doing nothing. I cant easily get it out to a garage since I dont have access to a van or the deep pockets needed.

The bike is factory engine wise other than a free flow exhaust.

So far I have:
Changed coils, spark plugs
replaced carb gaskets, float needles, idle jets, main jets,
new battery

Diagnositics
Tried running with petrol cap open and shut (no difference)
Checked pump operation
Checked float levels
checked diaphram for damage
reset mixture setting to factory (+plus 1 turn to take into account the exhaust)
Inspected fuel bowls (clean)

the most recent item was the float needles - i though perhaps it was getting over fuelled. After I rebuilt it all - again, runs perfectly for 3 miles and then i have the issues.

The issues are that it will idle pretty happily but opening the throttle past 3k will result in the engine 'hunting' and dying out. Adding choke just makes things worse.

To me it seems like its got to be the carbs, I just cant tell what difference it is making when i pull it apart and rebuild it. Everytime it purrs after the build and im grinning like an idiot for those 3 miles....

I am a member of the FJ1200 club but they dont seem to have an on onlline forum - just a few pdfs and the occassional magazine. Any last advice before i weigh it in for scrap?
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FJ1200 3CV

[jaffa90]

"""The issues are that it will idle pretty happily but opening the throttle past 3k will result in the engine 'hunting' and dying out."""

Ok so it`s dying out, will it run again up to 3k afterwards?

Free flow exhaust ! Don`t live near me.

[BristolFJ1200...]

[jaffa90]

Ok, you cannot check the plugs for being wet with fuel or dry due to the plastics & the tank, so when it starts to die out did you try to give it more throttle and then stop to smell the end of the exhaust for neat fuel?

[WD Forte]

Op dont say what year but will guess post 1988 as some fudgies have this odd reserve switch arrangement
where a low fuel sensor sends a signal to the igniter box and this makes it run like a bag of shit until it 'senses' it's been switched to reserve.
Whether it interrupts fuel flow or sparks to remind riders to switch to reserve appears to be a debatable topic

Erratic sensor signals from old sensor and connectors could give it all manner of conniptions.
so....
Assuming the carbs are there or therabouts and it isn a choke stuck on
and bearing in mind its circa 1990,
I'd be giving the electrical side of the fuel system a feckin good look over not just listen to a brief buzz/click from the pump and assume it's all tickety boo.
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bikers smell of wee

[jaffa90]

Also after reading WD Forte reply, i found this.
https://www.motorcyclenews.com/new-rider/choosing-kit/2011/june/jun1411-yamaha-fj1200-fuel-cut-off-woes/

[BristolFJ1200...]

[BristolFJ1200...]

Just as an update - i checked the fuel line for kinks and its fine. I used a petrol can as a temporary fuel tank - direct to the fuel pump - by passing the fuel filter (fuel filter is transparent and looks clean)

I also checked the reserve solenoid and it is working.

starts up easily and idles, sounds healthy - no popping, even idle - all cylinders but at 3k rpm hunts and dies out again.
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FJ1200 3CV