1986 fj1200 driveability issues

[Pat Conlon]

Weber, when opening the throttle, the needle rises within the emulsion tubes (nozzles) which allows gas to flow out of the little holes, with the lowest holes first, then as the needle rises more, the middle and upper holes last.
If you have a hesitation, look closely at those lower holes.
You must remove the tubes to properly clean them.  You're making progress. Kudos!  Pat

[weber1]

That makes perfect sense. I realized that what I thought was the emulsion tube wasn't. I was looking at the small brass tube with the one pin hole in it that went into  the float bowl housing. I will not be surprised to find those lower holes restricted Pat. The bottom of the bowls had jellied fuel in them and a hardened calcium type residue also. It's been awhile since I've played with carbs. Thanks for the help.

[SlowOldGuy]

As Ed said, be VERY sure the idle circuit and components are clean.  You should also check the fuel/float level.

DavidR.

[flips]

When you take the fork caps off, be quite careful.  The fact there's "preload spacers" under them should be a tipoff... they're spring loaded, and you can quite easily shoot yourself in the face with them if there's enough tension.  You'll need a very good grip on your tools and a bunch of downforce while unscrewing them to prevent surprises.

+1 on that!....nearly knocked out a couple of teeth the first time I did it...

Cheers

Jeff P

[weber1]

OK here's the update. I cleaned the carbs again, removed the emusion tubes and cleaned them well. I ran a thin wire thru the pin holes and cleaned the housings and the needles.  I'm at 95% running correct. Still still have a slight tip in concern and by that I mean it feels like a miss, throttle up and it is a rocket. Now, I did notice that the second Carb from the left did not have the same amount of pinholes as the other three. I'm wondering if this Carb kicks in at a higher rpm and this is the reason for the feeling at low rpms. I have a mercury outboard that has a cam on the throttle linkage that kicks in two carbs at a certain throtlle angle for fuel economy and power need, like secondaries on a Carb. I also have to sync carbs. I will say that if I pull the choke out just a little the throttle snap response is perfect. Also  would like to know correct ngk plug number and gap, I have new ones and want to make sure they are correct.

[racerman_27410]

all emulsion tubes have the same number of holes..... i think you are going to have to revisit the inside of the carbs again.

third times a charm 


Dont feel bad ... it wont be the first time that it's taken someone more than a couple of attempts at cleaning the FJ's carbs.

ultrasonic cleaning is the best method but if thats not available then you are taking the only path thats left.

do you also have a way to balance the carbs?

KOokaloo!

[cyclenutk75]

Also  would like to know correct ngk plug number and gap, I have new ones and want to make sure they are correct.

NGK plug is DP8EA-9, gap is 0.8-0.9mm (0.031-0.035").  Good luck ironing out the issues.  It'll be worth the time invested.
GT

[weber1]

Again huh? OK, I have it down now! I went over that emulsion tube the other night and it was symetrical and I could swear there were only about six pin holes. I will look at it again. Any chance it may have been swapped? Someone else was here before me I can tell. I do have a way of syncing carbs and will do after I solve this emulsion tube issue. Thanks for all the inputs.

[Arnie]

While you're in there again cleaning the emulsion tubes.... you may want to inspect them very critically for 'ovalness'.  Over time, the needles rattle and reshape the emulsion tubes from round to oval.  You may want to just replace them all.  (not too expensive, from rpm or other mikuni sources)

Arnie

[weber1]

Thanks. I took the carbs off again and checked the 2nd carb from the left because of difference in emulsion tube. Cleaned and reinspected and found it only has 6 holes at upper portion. It has 4 stacked at 180 degrees from each other and 2 more lower at 90 degrees from prior 4. I took a 1/16 drill bit and put one hole near base of tube and one more 1/4 inch higher. On road test after a quik adjust it is alot better. still have a flat spot on a hard snap. I am going to order all  new tubes and see how it goes.

[weber1]

OK-Here's the update. Put a new nozzle in all four carbs. Set gap on all 4 plugs adjusted carbs (still have to sync them) set idle and went. Almost perfect still alittle miss on initial go from stop but barely noticable. Thanks for all the help, you guys are great. Next will be the front forks, bottoms out bad. Thanks again, Rob.

[racerman_27410]

i would go ahead and synch the carbs so you can fully enjoy the fruits of your labor.... it does make a huge difference in how the engine feels and performs.



KOokaloo!

[weber1]

So-I take the bike out for a ride this morning. A few passes up and down the street and things were good,then, I lost a cyinder. #4 lost spark. removed the coil for the #1 and#4 , no broken leads. any common problem or is the coil bad, anyone know how to test it?

[andyb]

You sir, need a shop manual. 

Probably the most important thing in the toolbox!

[Pat Conlon]

If it was the coil, and you lost #4 you would also lose #1. FJ's use a wasted spark. I suspect its a plug wire or a plug cap, not the coil.
As Andy mentioned in another post, switch #4 and #1 plug wires. If the problem moves from the #4 cylinder to the #1 cylinder then you have your answer.

[edit] to check the coil's primary resistance, set your multi-tester to the x1 ohm scale and measure across the leads, it should read ~2.7 ohms.(+/- 10%) To check the coils secondary side (spark plug) resistance, set your multi-tester to the x1k ohm scale and measure across the 2 plug leads and it should read ~12k ohms (+/-20%)

I really think that you have a bad plug wire or plug cap.