Bike wont Idle..

[The999Kid]

Hi,

I have a 1986 Yamaha FZ400 (japanese grey import) and i wont sit and idle normally! It runs ok for a bike its age, and will happily see me upto motorways speeds and beyond despite being restricted to 33bhp through a custom made kit. It starts fine and will happily sit and run on the choke... but after i take the choke off and the revs dip below 1K the bike cuts out.

During a jolly jaunt from hatfield to croydon today... i lost count of the amount of times the bike cut out from me letting go of the throttle and the revs dropping off... very annoying especially with angry londoners behind you at the lights!

Any ideas?

Always grateful!

P.I.
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NDB 19/10/1989 - 1/11/2010 |Nowhere.Elyseum wrote: I get the distinct feeling that Tim should be our secret weapon for future trolling. I don't know many people that can rip the piss in Iambic pentameter

[Vincent]

Have you tried adjusting the tickover? Sometimes, instead of the carbs being set by the tickover adjusting screw, they are set by the adjustment on the throttle cable. After time, the throttle cable stretches and the tickover drops. You should only have to turn the tickover screw a very slight amount to make any difference, if you find you have to turn it more than half or a full turn, the problem is elsewhere. When was the last time the bike had a new air filter?
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[The999Kid]

[Vincent]

Not sure on the FZR, on some four cylinder bikes, it's a largish black platic knob coming out of one side, on others it's a small screw on the carb rail, (I suspect this is the case with the FZR). It's usualy within fingers reach wherever it is. Don't mess about with anything else until you know it's the right screw tho. If nobody else can tell you on here, try and find a manual, either service manual or even just a parts manual on line. If you had a pic of the carbs from the parts manual, I could tell you which is the tickover screw.

Air filters get negelected quite often, just like engine oil, fork oil and brake fluid.
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Space Is Deep

[yuri2085]

I neglect fork oil and am likely to continue doing so!

[Vincent]

[The999Kid]

Right, Just had the panels off not 5 minutes ago and the filter is pretty much good as new... its whiter than my teeth so its not going to be that...

as for the idle screw... fuck knows where that is... been staring at the carbs for at least 10 mins at every possible screw wondering if its that one or not... Havent removed the tank as... i dont know how....
could really do with someone who knows there stuff to point me in the right direction...

Pictures can be taken on request... failing that ill run it down the garage and have them sort it for me for an inordinate amount of money.
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NDB 19/10/1989 - 1/11/2010 |Nowhere.Elyseum wrote: I get the distinct feeling that Tim should be our secret weapon for future trolling. I don't know many people that can rip the piss in Iambic pentameter

[ZZR-Souls]

You should try here, if they don't know then you really are in trouble.
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[The999Kid]

[Blue_SV650S]

1k is fairly low anyway, its prolly supposed to be ~1200? You might want to consider getting the carbs balanced, that'll make it idle better/smoother too!!
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The purpose of life is to fight maturity.

[The999Kid]

Right... while im replacing the tank and the bike is tank and fairingless could someone point out to me the vague location of the idle screw... heres some pics of what i can see

Top View
https://i228.photobucket.com/albums/ee190/ProvectusIncurro/My%20Motorbike/Carbs1.jpg

Right Side
https://i228.photobucket.com/albums/ee190/ProvectusIncurro/My%20Motorbike/Carbs2.jpg

Left side
https://i228.photobucket.com/albums/ee190/ProvectusIncurro/My%20Motorbike/Carbs3.jpg
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NDB 19/10/1989 - 1/11/2010 |Nowhere.Elyseum wrote: I get the distinct feeling that Tim should be our secret weapon for future trolling. I don't know many people that can rip the piss in Iambic pentameter

[Stelmer]

On my 1985 GSX, the idle speed is underneath the throttle mechanism. It's a long bolt with a large black knob on it that pushes on the throttle lever where the cable attaches to the carburettor.

Yours could have something similar.

Turn it one way the revs should go up. Do it with the bike at running temp though. I set mine to idle at 1400rpm

Other than that, carb cleaning time.

[Vincent]

Here you go mate, it's the knob under that pipe in the centre:-

https://i77.photobucket.com/albums/j71/Drewskovitch/FZ400Ncarbs.jpg
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Space Is Deep

[The999Kid]

[The999Kid]

Ok.... bike now wont start despite 3 days of fiddling with the idle screw... it gets so close to starting and i can hear the engine trying to turn over but in the end im just draining my battery...

ideas?
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NDB 19/10/1989 - 1/11/2010 |Nowhere.Elyseum wrote: I get the distinct feeling that Tim should be our secret weapon for future trolling. I don't know many people that can rip the piss in Iambic pentameter

[el_oso]

unless you have touched anything other than that screw, then that is where your problem lies.
have you tried with and without choke?
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Car: Jeep Wrangler 4.0L

[The999Kid]

[D O G]

Plugs?

A couple of weeks ago I was thowing my bike down on the road and kicking it because it wouldn't start.

New plugs were the answer.

With a new bike (new to you that is), you never know what is or isn't working, or how long it was since it was last working, have a look at the plugs, do the old spark check - removing plug, holding sparking tip against the engine, turn engine over. Look at the quality of the spark if it is weak or non existant then your plug is likely to be fubard. The spark on mine was weak and 'wandered' about the tip, not bright blue and to the same location.