Running woes

[Plug]

 This might be a bit long but please bear with me.

Bought a 91 FJ1200a in April. Was a non-runner but with the addition of another bty, managed to get it going, but with the carbs pouring out fuel. Fine thought I, take off and clean and while I'm at it, put some new plugs in.
Run it up, no fuel leaking out. Great. Went out for a ride and guess what. Leaking fuel.
Gets it home and parks it up for a few days.
Went out to start it, no play.
Carbs off, blocked idel jets in 3 & 4. All cleaned up, back on. Still a real bitch to start, but start it did. Balanced them up no probs. Went out, died after a few miles and the motor felt a tad too warm for my likeing (Not sure how hot the FJ's are supposed to run) and a real bitch to start. But no fuel leaks.

Managed to get it home and all I wanted to do was to blow it up.
Thinking it was a fuel problem, sourced another pump. Works as it should.
Still no start. Carbs off again, all seems OK. No blocked jets etc
Next, lets try another CDI.
Great, starts first push when cold, revs fine.
Went for a test ride, 500 odd meters later dies. Opens fuel cap, fires up, dos a few miles no probs.
Took the fuel cap off, stripped and cleaned it (Big thanks for the file on here, a very big help )

Puts the cap back, fires up from cold no probs, gos out, dies (engine warm). Push it home, park in shed and go off in a big sulk.


I haven't pulled the plugs out yet to check what colour they are.
Had a few thoughts as to what it could be.
plugs breaking down already.
Coils going tits up when the engine is warm
Fuel pipe routed badly (had anyone got a diagram of how they should be?)
air filter blocked up. Its on the list of new bits to get on payday

On the subject of air filters, would it be worthwhile putting pods. Its running a Neta exaust system with standard jets at the moment

The thing is, when it has run OK its felt great, really smooth  handles great (compared to my GPZ which is a real handfull) and a real joy to ride.

Any ideas guys as this is really starting to piss me off

[racerman_27410]

check the routing on your fuel line and ,if you have replaced it, that the fuel line is not too long.

its sounds like a classic crimped fuel line.

KOokaloo!

[Plug]

Will have a look at them again.
The fuel lines are the ones the bike came with but they are 2 different types. The line from the pump to the carbs runs underneath the air box and is the armoured type. The one which comes from the tank is a normal rubber type with a spring around part of it which comes from the filter, down the side of the carbs, behind the bracket which holds the air box and into the pump. Should they both be the armoured type?

[Plug]

Just another quick question, while I think about it. Ref the fuel tap, when you take the pipe off, is it supposed to still free-flow fuel out?

[andyb]

That's a pump equipped model, check the filter while you're fooling with it.  

The gravity fed models are supposed to be nastier about fuel line routing, but the pump ones will also get snippy if it's not exactly perfect.  

On the fuel petcock (tap?  attached to the bottom of the tank, ya), it's just an open thing.  The pump itself is supposed to shut flow off for the most part when the bike is off.  No vacuum line actuation crap to deal with, hooray!

[Plug]

I put a new filter in when I cleaned the carbs so I know its not that. I get the feeling the solution is gonna be so simple, its stareing me in the face but I can't see it. Fuel pipe routeing dos seem a firm fav

[SkyFive]

I'm going to throw this out here, for what it's worth;

I just rebuilt a very nice set of carbs I got off of eBay, they appeared to be untouched and original but they had been dry for a while, how long I don't know. I spent an entire day, taking my time cleaning them, installing new jets, float needles and seats and setting the floats to precisely .880. The diaphrams looked like new as did the floats, emulsion tubes and main needles so they just got cleaned with the exception of the floats and reinstall. I set the mixture screws at 2.5 turns and pre-sync'd the carbs with a feeler guage. All of this I knew would at least get me running. Right of the bat I had a fuel overflow, I rocked the bike on the center stand thinking it might be a float needle, it seemed to slow down so I fired up the engine and it runs like crap and it was hard to start also. I pulled the plugs after a few minutes of running and the 1,3,4 plugs were black as soot, this was strange because there is no black smoke from the exhaust at all. Anyhow, after fiddle farting around with it for a couple of hours I'm convinced my floats are either sunk or nearly so becauuse I know everything else is correct because I double and triple checked my work.

I believe you are on the right track Plug, check your plugs and if you have to take the carbs back off check your floats/fuel level.

[mikeholzer]

I put a new filter in when I cleaned the carbs so I know its not that. I get the feeling the solution is gonna be so simple, its stareing me in the face but I can't see it. Fuel pipe routeing dos seem a firm fav

I've had to tow a few cars back to repair shops back in the day due to a fuel filter being installed in reverse during a tune-up. I don't know if that could be such a problem on a low pressure carbureted system as this (in each case, it was a GM truck running CPI - very fussy with their fuel pressure needs), but it's worth taking a quick peek at. Arrow on the filter points away from the fuel tap on the tank.

[Plug]

Thanks for the advice guys. Will let you know how I get on. Might be a few days before I can get round to having  a look

[RichBaker]

I'm going to throw this out here, for what it's worth;

I just rebuilt a very nice set of carbs I got off of eBay, they appeared to be untouched and original but they had been dry for a while, how long I don't know. I spent an entire day, taking my time cleaning them, installing new jets, float needles and seats and setting the floats to precisely .880. The diaphrams looked like new as did the floats, emulsion tubes and main needles so they just got cleaned with the exception of the floats and reinstall. I set the mixture screws at 2.5 turns and pre-sync'd the carbs with a feeler guage. All of this I knew would at least get me running. Right of the bat I had a fuel overflow, I rocked the bike on the center stand thinking it might be a float needle, it seemed to slow down so I fired up the engine and it runs like crap and it was hard to start also. I pulled the plugs after a few minutes of running and the 1,3,4 plugs were black as soot, this was strange because there is no black smoke from the exhaust at all. Anyhow, after fiddle farting around with it for a couple of hours I'm convinced my floats are either sunk or nearly so becauuse I know everything else is correct because I double and triple checked my work.

I believe you are on the right track Plug, check your plugs and if you have to take the carbs back off check your floats/fuel level.

Old, bad, leaky inlet needle seat o-rings......... unless you already replaced them. If not the o-rings, weigh each float individually, a leaky one will be heavier...

[Plug]

Managed to get out for an hour or so today. Took the plugs out and the colour is fine. Right says I, next, have a look at the fuel line routeing. All seems fine.
I've now managed to get another set of coils for the great price of nothing. We like free
Took the fairing off in prep for changing them over (which dosn't take long as there only 8 bolts to undo and it falls off) and thought "I'd better check to make sure all the block connectors are actually connected properly" and what did I find, yep one of them wasn't pushed in fully. Tried firing it up and guess what..............it fired. Took quite a bit of time for it to warm up and settle down.  (might have been me knocking the choke off a bit early). Couldn't take it out for a test ride as by this time I'd had a beer but will do that at the weekend.
Fingers crossed.

[fj11.5]

you took the fairing off to change coils ? i must just have small hands lol

[Plug]

Quick update. Haven't got round to changing the coils yet but it is now starting better but dos seem to take a while to warm up. Is this normal?
When you try to rev it, it seems a bit spluttery and dosn't seem right.
Tried to take it out but as soon as you try and pull off it gos all sluttery.
Now could this be the coils (will change them tomorrow to see if this makes a difference) pick ups or carbs 

[Plug]

Another quick update, changed the coils, no difference. Looking more and more like the carbs. At least I'm ruleing out more and more as I go along

[ktmaha]

I, personally, have rarely seen ignition coils go bad. Check the spark plug caps. They will break down and leak spark along the seem. There is also an ohm spec for them. 5k or 10k, dont recall.
Also make sure the tank vent isnt plugged.