12003cv idle is no longer smooth

[ELIMINATOR]

My bike seems to be not running smoothly on the idle, and up to about 2,000rpm on low throttle. Open it up and it's as smooth as ever.

I've looked at various threads, and I'm praying I don't need to remove the carbs, that just frightens me.

A while back I fitted new silencers, although I don't think the problem is connected.

My fuel consumption seems to have got worse, although, I can't say if I'm riding it the same way.

I also noticed that occasionally the rev. counter doesn't move from start up for about a second or two, I know??? I assume that the rev. counter works via one of the coils, could this be related. Although the bike still seems to be not running correctly even when the rev. counter is working properly.

One other thing, when I turned the engine off the other day, when the sun was low. I noticed that a heat shimmer could be seen dropping out of a breather pipe, this is not one of the carb, overflow pipes. it's on the L/H side of the bike ( although at the bikes age, who knows if anything is routed correctly.) I put my finger on the end and sniffed to see if it was petrol, it wasn't.

Bike now shoved to the back of the garage.

[FJ111200]

What'sthe air filter like?   Blocked?  Holed?

Don't be frightened of taking the carbs off if need be.    Everything is part of the learning process, and a shed load cheaper than going to a bike shop.

[ELIMINATOR]

Air filter is less than 4,000 miles old.

[ELIMINATOR]

Needle seat O rings seem the likely culprit to me, see here.

http://www.fjowners.com/index.php?topic=46.0

Ah, I forgot to say, the bike pops and bangs on the overrun when rolling off the throttle.

[ELIMINATOR]

I'm sure it never used to, that would hint at too much fuel on idle?

[Pat Conlon]

When was the last time you sync'ed the carbs?

[ELIMINATOR]

About 4,000 miles ago. It is just the idle and up to about 2,000 rpm.

The popping and banging on the over run would probably remove the possibility of the carbs being out of balance?

[Bminder]

If it were my bike I would first guess would be that one or more of the idle jets (also called pilot jets) were plugged.
It's not that tough of a job to pull the carbs and clean those jets. I've done it so many times this summer I could probably do it blindfolded like a soldier has to clean his rifle. My bike sat for 3 plus years and was gunked up bad.
You can do it.

[ELIMINATOR]

Mate owns abike shop, so Ican use his sonic cleaning tank. Just a question of getting a round to it then.

[Bminder]

Once you get the tank to him, pull the carbs and clean the idle jets.

[Bminder]

If the idle jets are plugged, they wont' unplug themselves with a clean tank and carb cleaner in the gas. The holes in them are too small, you have to you take them out and clean them... ask me how I know 

[ELIMINATOR]

Just ordered four carb. gaskets and FJ11-12/XJ12/XJR13 S/S Screw & O-Ring Carburetor Kit    
FJ11-12/XJ12/XJR13 S/S Screw & O-Ring Carburetor Kit from Randy, well, I have to start somewhere
   

[RichBaker]

Onbce you get them apart, you'll be kicking yourself for waiting so long to do it.... These are MUCH simpler than the old Q-jets and such. No check balls or other little parts/pieces to go missing on ya....   

[ELIMINATOR]

Interesting...................... Parts arrived, I put them in the garage after showing them to the bike. As the tank is full, I used it to commute to work. Bike running normally, obviously the threat of me removing the carbs knocked some sense into it.

[Bones]

Yeah, even though these things are machines, I'm sure they've got a bit of human DNA in there somewhere. As soon as you say how good it's running to someone, it'll play up something shocking, and in your case with it running rough threaten to pull it's heart out and operate... it runs properly. It's happened to me several times and I'll just look at it and go" You Bastard"