86 fj 1200 running issue

[00davemag]

 Hi. I am new to the forum and have a question. My 86 fj1200 usually run fine but recently it has had problems. It will die for know reason at any rpm and with any level of fuel in the tank . Hot or cold ,freeway runs or just sitting in my garage warming up. I removed the carbs and reset the floats and cleaned the needles & seats . But it still does it. The only thing I found was the fuel petcock vacuum diaphragm was bad. Any ideas guys? I hope it is not the CDI ? Could it be coils or a bad voltage regulator? Can you test a cdi?   

[jack02]

Hello from a fellow newboy! A few years back I had exactly the same problem on my '89 3CV. One day it packed up and flatly refused to start again. So fortunate to be just half a mile from home,pushing a conked FJ any distance is no fun. Don't know about the potential problems you mention,but mine turned out to be a corroded cut-out switch - the one wired to the clutch and activated by the sidestand. I pulled it out and bypassed it -problem solved forever.

[Arnie]

Knowing that your petcock diaphragm is bad, I assume you're using the "prime" position when running, right?
CDI's are almost always either working or not, very rare to get intermittent functioning.
Could be a weak sidestand spring allowing the cut-out switch to chop spark.
Do you know if its dying from lack of fuel or lack of spark?

Cheers,
Arnie

[00davemag]

I am not sure if it is lack of fuel or spark. It will run but only with the choke partially on. But if you give it any throttle it will die. I am going to open it up this weekend.

[00davemag]

I also found the kick stand switch does not work. How do you by pass it?

[jack02]

I also found the kick stand switch does not work. How do you by pass it?

It's going back a while now,but if I remember rightly I just removed the switch completely and binned it (it's a sealed unit,nothing you can do with it). Then spliced the wires together which lead to the ones going to the switch. I should add to what I wrote earlier that I'd been having misfiring and intermittent cutting out for weeks before that final failure. Just a thought,but before you start ripping stuff apart why don't you get the bike idling on the mainstand and try jiggling the sidestand to see if that causes anything to happen? As for the clutch switch,can't remember doing anything to that. Course,if I engage gear now with the sidestand down,the motor keeps on running...

[SlowOldGuy]

I am not sure if it is lack of fuel or spark. It will run but only with the choke partially on. But if you give it any throttle it will die. I am going to open it up this weekend.

This is confusing since your first post said "usually run fine but recently it has had problems."  From the wording of your first post, I got the impression that you're running up and down the highway.  If you can't get out of your garage then your problem is significant.

Is this "it will only run with the choke partially on" behavior what you're describing as the "recent problems?"

If so, then I would think you've got a carb problem.  Especially "if you give it any throttle it will die."  That sounds like a carb problem to me.

If it only runs with the choke on then that's usually an indication of clogged idle jets. 

The sidestand switch should only be a factor if it was dieing in gear.  If it dies in neutral, then it's probably not the switch.

DavidR.

[fj1289]

Good chance too it could be battery related.  The FJ ignition system gets real testy without a good battery!

So, a little more info is needed for any "internet troubleshooting"!

Is this a sudden problem?  Or one that has gotten progressively worse?
Have you done any maintenace or mods recently?
Is it rideable at all now? 
Has it been setting for a while?  When was the last time you cleaned the carbs?
Does the battery hold a charge?
What have you tried so far to fix it or troubleshoot it?

[00davemag]

It started cutting out 2 years ago but it only happened a couple of times. It would happen on the freeway at first and now it does it is continuous. It will idle ok with the choke partially on and idles really low with the choke off. If you role the throttle it only goes up to 3 or 4 k rpm and then it starts to sputter and die. It pops out of the exhaust a little when you try and run the rpm's up. This is all with the bike out of gear in my shop. It has a new battery and it reads 14.5 to 15V at 3k rpm. I just got done testing the ohms for the ignition coils and checking for spark and it reads good. I tested the rectifier and it also shows good. I did an ohms test on the pickup coil and it reads at 185 the book shows it should be 108 to 130 . I pulled the carbs and cleaned them out and went through and checked all the electrical connections and did those test, that's all I've done so far     

[Dan Filetti]

It will idle ok with the choke partially on and idles really low with the choke off. If you role the throttle it only goes up to 3 or 4 k rpm and then it starts to sputter and die. It pops out of the exhaust a little when you try and run the rpm's up. This is all with the bike out of gear in my shop.      

I'm thinking you still have a carb problem.  The "idle ok with the choke partially on" is a clue -I'm assuming the bike is warmed up enough and that you've tried the obvious stuff, AKA adjust the idle screw.  Please confirm.

Not taking any real throttle is another reason I think you may need to pull the carbs again, and re-double your cleaning efforts.  This all sounds like symptoms of a clogged/ obstructed jet.  Have you downloaded and consumed David R's cleaning/ rebuilding instructions -they are quite useful.  I'm pretty sure they're in the files section...  Others may chime in with different opinions, but I'd bet $1. that it's a carb issue.

Good Luck,

Dan

[VMS]

Assuming you've checked fuel pressure? If it's not getting to the carbs...

[ren-dog]

Pops out exhaust indicates either:

faulty timing,
sticky valves, or
too much bloody fuel 

Needs choke to idle indicates:
faulty timing,
poor spark,
vacuum leak, or
too litlle bloody fuel 

Won't rev over 4K rpm indicates:
faulty timing,
poor spark,
huge vacuum leak,
sticky valves, or
too much bloody fuel 

Check/replace plugs,
Check for arcing plug leads,
Check coil and lead resistances when HOT,
Check for vacuum leaks,
Check valve operation and clearances,
Overhaul carbs.

Given the 'dies at any time' scenario,
I'd be betting on faulty coils, or wiring
plus a whole heap of other tune issues.

Hope that helps.
ren-dog out

[Pat Conlon]

Sounds like gas related to me, therefore;
1) Check the routing of your fuel lines, make sure they follow the oem route with no pinching and no added aftermarket fuel filters which may impede flow.
2) Check your carb vent lines (2) if a line is kinked, then your float bowls will not fill with gas.
3) Check your gas cap to make sure it's allowing air into the tank and not creating a vacuum as gas level drops while being fed to the carbs.
With my '84, I was losing vacuum intermittently at my petcock and the petcock was shutting off fuel to the carbs....What a pisser that was...Took me a while to figure that one out....

Let us know what you find...

[ren-dog]

3) Check your gas cap to make sure it's allowing air into the tank and not creating a vacuum as gas level drops while being fed to the carbs.
With my '84, I was losing vacuum intermittently at my petcock and the petcock was shutting off fuel to the carbs....What a pisser that was...Took me a while to figure that one out...

A vacuum lock inside the fuel tank
Is this common on the 84?

[Harvy]

I can't remember if this applies to '84 FJs.
On later models, the fuel cap has 2 little rubber valves in it......one to allow air in as the tank is emptied, the other to allow pressure out as the fuel vapourises when it gets hot.

They can stop working with age and require surgery.

Harvy