carb issues

[movenon]

+1 on the needle. Looks like the ones on my original set up.  Also check the slide spring it to would probably be also Dyno jet. I took all that out and went back to a full stock set up from RPM when I rebuilt the carbs. Well almost full stock. I ordered the adj needles from RPM. Replaced the slide springs with stock units.
Here is a pic of the spring. Stock one is on the left.

George

[Flynt]

The tip of the shroud of the emulsion tube will hold up the flat bottom slides.

Pat - you've said that several times, but I don't think it is true.  My '84 came with flat bottom slides and shrouded emulsion tubes (PO had swapped them in I guess).  No mechanical interference issues and the bike actually ran well.  My guess would be the shroud was added later to further increase vacuum seen by the main jet at high velocities in the carb body.  This might have evolved (along with curved bottom slides) to increase main jet flow at or near WOT and improve performance after the FJ had been out for a while with the small main jets required by emissions testing...  speculation I know, but I think it makes sense.

I returned my carbs to the proper unshrouded e-tubes and tuned them via the Factory Pro procedure...  they work well now, but have MUCH bigger mains largely to keep from going lean at near WOT.  I think the shroud would help with this (based on above conjecture) and allow smaller mains, but haven't spent enough time to prove or disprove.  

Frank

[Tuneforkfreak]

 I sure am learning allot about these carbs watching you guys diagnose this issue.

[FJ_Hooligan]

Having the wrong jet needles would explain why it's so rich.  That needs to be addressed.

Going back to your previous comment about spitting and farting, I think you have one or more idle circuits that are not in good shape.

You could chase your tail for many months on this.  Get with RPM and get a quote on what it would take to get your carbs sorted.  If you enjoy riding your FJ then whatever he quotes is well worth it.

Randy and Robert are good people.

[FJ_Hooligan]

I returned my carbs to the proper unshrouded e-tubes and tuned them via the Factory Pro procedure...  they work well now, but have MUCH bigger mains largely to keep from going lean at near WOT.  I think the shroud would help with this (based on above conjecture) and allow smaller mains, but haven't spent enough time to prove or disprove.  

Frank

I remember working on an early '85 model FJ that had the flat bottom slide.  It had an early Dyno Jet kit installed.  The jet needles were these HUGE blunt rods and the DJ main jet was a 180!  Totally different than what my '85 had with the curved slides and shrouded emulsion tubes.  My Dyno Jet kit was way different using 110 DJ mains and the 144 air pilot jet.  I bumped the idle jets to #40 and the thing is absolutely perfect.

[Pat Conlon]

Hello Frank, my experience was different than yours.
At the 100k mile mark on my bike I felt it was time to replace my e-tubes. Unknowingly I put a set of new shrouded tubes on my flat bottom carbs and I could never get her to idle right. Idle was just ok, a bit rough, definately not as smooth as it was with the old (unshrouded) tubes.
Yes, there is interference with the shroud and the bottom of the (flat bottom) slide.
I ran my bike this way for another 35k miles until it became time for some top end engine work.
Randy noticed this condition with the shrouded e-tubes when he rebuilt my engine. He called my attention to it. He also could not get my old carbs to idle right.....and if he can't, nobody can.
I've since converted over to the later carbs and all is well.

Yes, yes, yes, Randy knows his stuff on these carbs, as many satisfied customers will testify, inc. myself.
I agree 100% with Hooligan.

[ergojack]

You are correct that they are D.J. needles. What puzzles me is that those needles (according to receipts & records) were installed nearly 20 years ago and the bike ran
very well for all those years. I see and ride with the P.O. often, but he is a tinker who loves to mess with things.  The last time I rode this bike was probability 2 or 3 years
before he stored it.  He doesn't remember doing anything to it, or remember any running issues before he stored it. That being said, he is old and cursed with CRS so
there is just no telling. It is also possible that the P.O. replaced the D.J. needles with some others sometime before he stored the bike and created this slow running problem.
 

[Tuneforkfreak]

I think you have got it in your mind that a dirty pilot circuit can only cause a lean running issue, like if its clogged then it can only lack fuel and that can be the only outcome. I'm not a master tech mechanic but I do have a general idea of how that fuel gets pulled from that jet, its not pushed out, its not pumped out, its pulled out by way of vacuum/suction from the piston. Now, if those circuits are dirty BEFORE the air reaches the jet, would it not decrease inlet air thus pulling more fuel by default? Ever since I started reading this thread I couldn't accept that your carbs had problematic wrong parts installed, the bike ran for many years on those same parts.The only variable that ties your issue to other known issues is that those carbs sat for many years.  I know you soaked them carbs for 24 hours, did you run them through an ultra sonic cleaner afterwards? My thoughts are this, you don't have those carbs clean enough yet, you only think that you do. If you ran them through the ultrasonic with vinegar/water mix,  I'd suggest atleast two or three more cycles through the ultrasonic with maybe straight vinegar this time. Its been said several times in this thread by many different guys that dirt is more often than not the main culprit for your issue, you as a master tech mechanic know this as well. I can tell you this, I think you have one of them carbs cleaned properly. You're focusing on the 3 carbs running rich when you should be asking yourself, why does the one carb run perfect? After all,it has the same parts as the other three that are rich.

[ribbert]

I understand that is a no-no. Putting different slides into the bore of a carb. The slides are closely mated to the bore. That's why when rebuilding you need to track which slides come out of which carb, just so you are sure not to mix them up and put different slides into different carbs...

.....and the issue of slide vs carb bore mating

Pat, why does this matter?

Noel

[Pat Conlon]

Hey Noel, this is something I've been taught and the best I can figure is to prevent or reduce the rattling of the slide.
When the slides rattle, the needles also rattle causing wear on the needles and emulsion tubes.

[Flynt]

Yes, there is interference with the shroud and the bottom of the (flat bottom) slide.

OK...  I'll check it when I'm in there next.  I'm pretty sure mine didn't touch the slides, but whatever.  The shrouds go with the curved bottom slides by design and no argument there.  That's why I got rid of the shrouds.  I will say that tuning the flat bottom, shroud-less carbs is a bit of a bitch, very finicky at 3/4 WOT.  The curve/shroud design is an improvement in ease of use at least (for some reason)... 

Frank

[Pat Conlon]

Yeppers Frank, I'm sure the curved bottom slides and shrouded e-tubes are a superior design.

What I'm unsure of...are there also internal differences in the carb body? Different air/fuel/choke passages?

[Pat Conlon]

You're focusing on the 3 carbs running rich when you should be asking yourself, why does the one carb run perfect? After all, it has the same parts as the other three that are rich.

^^^ That is a very valid point, why indeed?

[ergojack]

If you go back & look at the plugs, you will see that in low speed test #1 with all fuel levels set low, (floats set high) cyls. 2 & 4 were running clean, #3 was badly carbon fouled & #1 was slightly carbon fouled.
Low speed test #2 with all float levels set to 23mm (fuel levels at normal), cyls. 2,3 & 4 were badly carbon fouled and cyl. #1 was getting fouled, but not as bad as the others.  There is no perfect running cylinder.  I have no doubt that if I went back & set the fuel levels low again, it would run as it did in test #1. I also believe that in test 2, #1 would have fouled out also if the bike had run long enough. As it was, I barely made it back to my shop.  It seems obvious to me that the problem is across all 4 carbs.

[Tuneforkfreak]

OK lets go back to some things you've said then. You replaced the float needles, you did not mention changing the seats along with the needles, so one would have to ask, did you change them as a set? I know you're gonna come back and say "every mechanic knows you change needles and seats together" but you're on a forum trying to diagnose an issue with the help of multiple people and the tiniest bit of info cannot be left to the imagination. You've said adjusting the float level has changed rich/lean conditions somewhat so lets just stick to that area for now. Do you have the needles installed on the floats correctly? If you have them backwards the retainer spring can drag on the float lever ( or at least on my 90 carbs they can).  You said yourself that your eyes are not what they used to be and your issue with these carbs, at least in my mind, has to be some little over looked step giving you fits.

1) Needles and seats installed correctly

2) Floats adjusted properly

3)Pilot screw has 1) O ring , 1) washer and a spring then is set

Outside of everything being spotless clean, the proper jets installed and the slide needle being set to proper height, these are the variables within your control to get that fuel into that cylinder properly. 99.999% of the time a guy would put these together after a thorough cleaning and never look back. What did you do differently that puts you in that rare .1%?