I posted this in the yahoo forum also.
I thoroughly cleaned the carbs on my '86 FJ and have installed them back into
the bike. The bike has 12K miles and sat for about 16 years in a garage unused.
I used Carb Dr. David Rathforth's kit with the new float valve seat o-rings and
stainless allen screws.
I got the engine idle stable and synced the carbs. There is a K&N filter, jet kit
installed and a 4 into 1 V&H pipes. Idle/air screws are 4 turns out.
The problem i am experiencing is a high idle situation. I can get the bike to
idle smoothly around 1100 RPM in the driveway by adjusting the idle screw BUT as
soon as i get down to the corner of my street, the tach reads a steady 2,000
RPM. Blipping the throttle does not bring the RPMS down. I have tried
readusting the idle down to 800 RPM, idles fine in the driveway, take it down
the street and same prob 1900-2100 RPM steady.
I took the bike out on a main road and it pulls strong with no stumbling or
misfiring, jumped right to 75 MPH in a hurry!
Any good advice would be greatly appreciated with this prob. I did notice a
tiny amount of fuel seep out of the the number 2 carb choke circuit hose. I took
the carbs out and made sure the float needle valve was closing before the float
hits the top of the carb body. It seems to be adjusted properly, but there
still is a couple of drips coming out of the hose.
The bike fires right up without any hard starting problems.
Thanks
Ozz
(Glen)
UPDATE*
I went to put the bike on the center stand this morning after letting it sit in the garage all night. Fuel started to flow out of the #2 carb black choke circuit tube pretty heavily for a few seconds. I am assuming now that the float/needle are sticking or leaking?
Ozz
(Glen)
Have you checked the Float LEVEL? Apparently the floats sometimes need to have thier tangs bet some to ensure the correct level. Also, I've heard where smaking the offending carb with a screw driver can, occasionally dislodge a stuck float.
Just a though,
Dan
Glen,
sometimes ya gotta rough up the needle and seat a little bit with some 800 grit sandpaper and then it will seat properly.
4 turns sounds too far on the mix screws. most of us start at 3 turns and go up or down from there.
Quote from: Mark Olson on August 25, 2009, 02:54:23 PM
4 turns sounds too far on the mix screws. most of us start at 3 turns and go up or down from there.
Yes you are right Mark, i adusted that to about 3 turns out right now and i think they can go in a little bit more. When i blip the throttle the tach shows the RPM's coming down slower than I'd like to see. Seems anytime I take the thing past 3K rpms, it takes a while for things to come down to the 1K rpm. Sort of like the throttle is stuck open, but its not.
I also disconnected and plugged the vacumn line going to the spark advance box, thanks to a suggestion an FJ Yahoo group member gave me. That seemed to help big time. What exactly does that box do??? On the test drive the bike seems to run perfectly normal, I never really took it over 4500 RPM without a problem occurring.
This morning I changed out the float/valve and seat on carb #2, and the leak looks like it has stopped. I did not see any overflow out of the carb choke circuit tube while tuning the carbs today. That was a plus. I have bent up the tabs on the other floats which seem to be okay. I checked the amount of gas that was in each bowl and it appears to be about 50-55cc each.
Rechecked the sync and that is pretty much on the money.
Appreciate any further advice.
Thanks
Ozz
(Glen)
Today I pulled the tank and backed the idle/air screws out to around 2.5 turns. I was able to get the bike to idle but anytime i went to blip the throttle the engine would shut down. So i increases the idle screw a little bit and set the I/A screws out to 2.75 turns. Bike idled okay and I synced the carbs.
Then i decided to spray some brake cleaner around the intake boots and noticed the RPM's jump way up when #3 cylinder was sprayed. Turns out the clamp wasn't on tight enough. So i snugged up all the clamps and double checked everything. Checked the sync again, all is good. At this point the bike is idling around 1200 rpms. When i rev it up to 3K RPM and let off it seems to drop steady till about 1600 rpm, then takes it time to settle back down to 1200rpm.
I took the bike for a very small ride down the block. It seemed that when I accelerated (3-4K rpm) and let off the throttle or pulled in the clutch to coast to a stop the engine wasn't "racing" as high like in the past around the 2K rpm mark. Tomorrow i will do a more thorough road test and report what results i get.
Take care
Ozz
(Glen)
Another update:
Well today i started the bike and i thought it seemed to run fine. Idle dropped down pretty smoothly from above 3K RPM. The tach still slowly drops down from 1600 to 1200 rpm. Then it idles okay for about a minute at 1100-1200 and then suddenly drops to about 900-1000 for about another minute. If i dont blip the throttle at that point and bring the rpm's back up, then the engine will just shut off on it's own.
If i hit the starter button the motor fires right back up no problem. Then we start the whole cycle over again.
SO this made me think the idle was to low. I adjusted the idle screw and it idled nice and steady at 1200 RPM. Well.......... then I went for the test ride and i'm back to a high reving engine that wants to stay in the 2,000 RPM range for awhile until slowly coming down to around 1500rpm!!! Ouch, this problem is driving me nuts! Then it wouldnt come down below 1500, so i turned the adjustment screw back. Now it will idle at about 1100-1200 but eventually stalls out on its own if i dont goose the throttle after a minute or so. Idle/air screws are still out about 2.75 turns each. Should i turn them in and raise the idle screw??
Any new ideas? George i did not run wire through those 3 or 4 little holes above the butterfly plate in the carb body...its about the only thing i haven't tried but i'm considering it if no other easier solutions come about.
Thanks
Ozz
How did you sync the carb? Are you sure you did that correctly?
Yes, cylinder 1 to 2 , then 3 to 4 , then 2 to 3. I use a mercury sync tool.
If it's reving up then air is somehow sneaking into the intake. You won't fix it with the idle mixture screws. Jacking the idle mixture screws should not cause this kind of behavior, there's just not enough air volume involved.
How do the rubber tips on the choke plungers look? Is the choke cable and plunger rod allowing the plungers to fully seat? It would be very easy for air to get in through the choke circuit if the plungers are leaking.
That is sometimes why the choke air intake hoses leak fuel. A sticking choke rod can allow enough airflow to pick fuel up from the float bowl, but the vacuum is not enough to deliver it all the way to the intake. Therefore it will fall back down and find its way out the hose.
Either that or you've got a sticking throttle cable.
DavidR.
Correct me if I'm wrong David R.
Carb #3 is static, the only way to adjust #3 is with the idle screw. This is why idle should be roughly correct before you start.
Sync #4 to #3. The right bank is now correct.
Sync #1 to #2. The left bank is now correct.
The screw between #2 and #3 balances the left bank to the right bank.
Everything goes off of #3.
When your idle changes after all of this bring it back to about 1k rpm.
Repeat until all is good.
This all needs to be done with the bike warm i.e. operating temp.
I do my sync'ing with the rpms around 1200-1250 rpm because that is where I get the best sync on my carbs.
Jason,
You are correct!
DavidR.
Synch can cause these symptoms of a hanging high idle as you describe.
I synch at 3k, from some old guru's advice (at a third of redline, half of peak torque, or near the revs you normally ride at if there's a nasty vibe spot there).
If you take the bike down the block and it hangs the idle high when you're coming to a stop, try this: Put the bike back into gear (1st) at the stop, hand off the gas, and gently feed clutch until you pull the motor down to the regular idle. Pull clutch back in. If the idle stays low, your synch/air is bad. If it revs back up, you have a fuel leaking added fuel someplace (check the orings around the needle seat assembly and the needles/seats themselves).
Also make ABSOLUTELY sure that the motor is fully hot when you're doing the sync. As it heats up, valve tolerances change among other things, and it's rough to get things right.
Worked for me in the past (my sync was bad and it drove me NUTS until I figured it out). Gluck!
Quote from: andyb on August 29, 2009, 03:12:02 AM
Synch can cause these symptoms of a hanging high idle as you describe.
If you take the bike down the block and it hangs the idle high when you're coming to a stop, try this: Put the bike back into gear (1st) at the stop, hand off the gas, and gently feed clutch until you pull the motor down to the regular idle. Pull clutch back in. If the idle stays low, your synch/air is bad. If it revs back up, you have a fuel leaking added fuel someplace (check the orings around the needle seat assembly and the needles/seats themselves).
YES! That is exactly what happens, i can bring the idle down by doing the first gear 'trick'. It will not rev up on its own. So good chance my sync sucks. Hmmmm, thought i was doing it right. I need to figure out how to get the sync correct. Suggestions?
I have been warming up the bike before syncing, and having it idle around 1200 rpm.
Quote from: SlowOldGuy on August 28, 2009, 09:04:13 PM
If it's reving up then air is somehow sneaking into the intake. You won't fix it with the idle mixture screws. Jacking the idle mixture screws should not cause this kind of behavior, there's just not enough air volume involved.
How do the rubber tips on the choke plungers look? Is the choke cable and plunger rod allowing the plungers to fully seat? It would be very easy for air to get in through the choke circuit if the plungers are leaking.
That is sometimes why the choke air intake hoses leak fuel. A sticking choke rod can allow enough airflow to pick fuel up from the float bowl, but the vacuum is not enough to deliver it all the way to the intake. Therefore it will fall back down and find its way out the hose.
Either that or you've got a sticking throttle cable.
DavidR.
The throttle cable is definetly not hanging up..that works fine. The choke plungers look good and seat closed. I don't think any air is getting in there. The bike won't tac up on its own, it just doesnt like to come down off of high idle after taking it down the street. I am certain now that all the carb intake boots are sealed properly by spraying brake clean around them and not noting any RPM fluctuation.
Quote from: Ratchet_72 on August 28, 2009, 09:57:03 PM
Correct me if I'm wrong David R.
Carb #3 is static, the only way to adjust #3 is with the idle screw. This is why idle should be roughly correct before you start.
Sync #4 to #3. The right bank is now correct.
Sync #1 to #2. The left bank is now correct.
The screw between #2 and #3 balances the left bank to the right bank.
Everything goes off of #3.
So i should adjust the idle air screw on #3 until it is equal to number 4? I thought turning the screw on the right bank adjusted 3 to 4? Confused :scratch_one-s_head:
Quote from: ozzstar on August 31, 2009, 09:26:31 PM
So i should adjust the idle air screw on #3 until it is equal to number 4? I thought turning the screw on the right bank adjusted 3 to 4? Confused :scratch_one-s_head:
WHAO! You aren't using the IDLE MIXTURE SCREWS to adjust sync are you? If so, then you need to consult a parts list or manual to find the SYNC SCREWS.
Adjusting the idle mixture screw will not affect sync. Sync is purely a measure/adjustment of air passing the throttle plate. If the follow the correct procedure, you will end up bringing all the carbs to read the same as the #3 carb. Then, when you turn the IDLE SPEED adjuster, the vacuum reading on ALL the carbs will change together. Hopefully it all changes the same amount, but there could be a slight tweak required when adjusting idle speed.
Confusing? Clarifying?
DavidR.
Quote from: SlowOldGuy on August 31, 2009, 09:40:31 PM
Quote from: ozzstar on August 31, 2009, 09:26:31 PM
So i should adjust the idle air screw on #3 until it is equal to number 4? I thought turning the screw on the right bank adjusted 3 to 4? Confused :scratch_one-s_head:
WHAO! You aren't using the IDLE MIXTURE SCREWS to adjust sync are you? If so, then you need to consult a parts list or manual to find the SYNC SCREWS.
i was responding to the earlier statement by forum member Ratchet: "Carb #3 is static, the only way to adjust #3 is with the idle screw." There is no confusion to me what screws open and close the butterfly valves for the sync.
There are more than 2 ways to skin a cat and sync carbs? right? I use a carb sync tool which has 4 vacumn hoses. David please clearify this for me.... if i connect all 4 tubes at once to the carbs, have the engine warmed up and idling at 1200 RPM, and have all 4 levels of mercury even at the same level... is my sync correct? This is how simple i think it is...am i correct? Otherwise i must be missing something.
Thanks everyone for your help so far, i want to get this puppy running correctly!
The idle screw refers to the LARGE knob below the center of #2-#3 carb, only accessable from the float bowl side of the carbies. I typically adjust mine with a flat blade screw drives, used as a pushing tool on either side of the knob to change idle speed higher or lower.
Hope that clears things a little.
My 2ยข
Quote from: ozzstar on August 31, 2009, 10:04:38 PM
i was responding to the earlier statement by forum member Ratchet: "Carb #3 is static, the only way to adjust #3 is with the idle screw." There is no confusion to me what screws open and close the butterfly valves for the sync.
There are more than 2 ways to skin a cat and sync carbs? right? I use a carb sync tool which has 4 vacumn hoses. David please clearify this for me.... if i connect all 4 tubes at once to the carbs, have the engine warmed up and idling at 1200 RPM, and have all 4 levels of mercury even at the same level... is my sync correct? This is how simple i think it is...am i correct? Otherwise i must be missing something.
If you have accomplished the same reading on all 4 carbs, then they are synced. Sorry for my confusion, you are correct, there are several ways to explain the process and achieve a proper sync. It sounds like you're on the right track.
I still can't believe your sync is off enough to cause the high idle. I'm not sure the sync can be far enough off to even cause this symptom. Then again, I wouldn't really know since I've never had a sync that far out. Still seems like an air problem to me. One way to test the choke plunger sealing is to blow into the choke air intake on the carb and see if it raises the vacuum slide. I know, you said you thought this was good, but it may still be worth eliminating.
If you have the 2-piece throttle cable, have you ever lubed the upper cables?
DavidR.
Keep in mind that the idle screw positioned in FRONT of the carbs adjusts ALL of the butterfly openings on the 4 carbs and is the only way to adjust #3. None of the other screws will adjust #3. This is because one of the carbs must be a reference point for the OTHER 3 carbs,
I know this is semantics but must be stressed. You'll just confuse the issue if you say "adjust 3 to 4"
Everything adjusts off of #3.
4 to 3
1 to 2 OR 2 to 1 doesnt matter
L bank to R bank OR R bank to L bank doesnt matter
If I had my extra bank of carbs handy I'd take photos but I don't.
Still confused? Is your Choke releasing fully? That may be the cause of a high idle. Maybe the choke cable is adjusted too tight and isnt allowing the plungers to fully release.
Quote from: Ratchet_72 on September 01, 2009, 10:22:52 AM
Still confused? Is your Choke releasing fully? That may be the cause of a high idle. Maybe the choke cable is adjusted too tight and isnt allowing the plungers to fully release.
Yes, i believe the choke is releasing all the way, i have watched the cable and the amount of tension/slack in the cable. If i pull out the choke knob when the engine begins to slowly loose idle and stall, the RPMS will jump right up w/o a problem.
Quote from: SlowOldGuy on August 31, 2009, 10:59:56 PM
Quote from: ozzstar on August 31, 2009, 10:04:38 PM
If you have the 2-piece throttle cable, have you ever lubed the upper cables?
DavidR.
No I have not lubed the upper cables since i got the bike. The throttle cables could stand to be lubed but are not binding or sticking. The throttle grip snaps back sharp. As i mentioned earlier when the RPM's come up after going down the street for a quick ride, and then it hovers around 2000 RPM, at a stop sign, i can put the bike in first gear, let out the clutch (without any additional throttle) and the RPM's drop down, and tend to stay down, but eventually the idle will drop low enough to cut off.
I still need to get some clear tubing and do the float level check. Currently there is no more fuel coming out of the choke circuit hoses.
Having the tank off to check things over i noticed that the tank petcock i have now is leaking. It has a slow drip out of the main fuel supply nipple. What can i do to correct this? Rebuild kit? Seems when the tank is hooked up on the bike i don't have any gas leaking out overnight, so i assume the floats are working properly. Is this something to be concerned about?
Thanks
Quote from: ozzstar on September 01, 2009, 07:57:17 PM
Having the tank off to check things over i noticed that the tank petcock i have now is leaking. It has a slow drip out of the main fuel supply nipple. What can i do to correct this? Rebuild kit? Seems when the tank is hooked up on the bike i don't have any gas leaking out overnight, so i assume the floats are working properly. Is this something to be concerned about?
I'm waiting for Dan to answer this question in firey, gory detail, but I'll just preview the answer with a YES! Definitely glue the outlet pipe back into the body of the petcock. I have a tiewrap around mine to prevent it from falling out.
DavidR.
I guess it's time I get back up on my personal soap box.. and what a nice lead in...
To David's point, that little $.50 piece of poorly designed petcock fitting cost me my '85. She burned to the ground, with nothing left that you could even recognize as an FJ (well, some folks on THIS list may be able to discern that it was what was left of an FJ, but not many...) In the end, the tow truck driver dragged the charred hulk up onto a flatbed, like the piece of lifeless, never to go again, metal that it was. Just 30 minutes earlier it had been my shiny FJ, with whom my wife was certain, I was having an affair somehow.
Like you, I noticed that it was loose. I tapped it back in with a small hammer. I was foolish to assume that was enough. It worked itself loose while I was riding and when she went up, with me on it, the fire ball was I'm told, 8 feet in diameter. In all seriousness, and I just can't stress this enough:
Seal and Twist-Tie those Fittings
It's one of the few serious design flaws of the FJ, and there are potentially dire consequences for not addressing. :bomb:
Climbing back down off my soap box now...
Dan
Quote from: Dan Filetti on September 02, 2009, 09:02:49 PM
To David's point, that little $.50 piece of poorly designed petcock fitting cost me my '85. She burned to the ground, with nothing left that you could even recognize as an FJ (well, some folks on THIS list may be able to discern that it was what was left of an FJ, but not many...) In the end, the tow truck driver dragged the charred hulk up onto a flatbed, like the piece of lifeless, never to go again, metal that it was. Just 30 minutes earlier it had been my shiny FJ, with whom my wife was certain, I was having an affair somehow.
Like you, I noticed that it was loose. I tapped it back in with a small hammer. I was foolish to assume that was enough. It worked itself loose while I was riding and when she went up, with me on it, the fire ball was I'm told, 8 feet in diameter.
Well, if that tale didn't shiver me timbers! Actually went looking on a parts fiche to see what an '85 petcock looks like -- just like the petcock on almost every bike I've ever ridden.
There's nothing like a story like that to remind us all that every time we let out the clutch we're balancing a 5-gal. Molotov cocktail between our knees, right over the ignition source...
Sorry about your loss, Dan. Thanks for sharing your experience!
Quote from: SlowOldGuy on September 02, 2009, 07:54:37 PM
I'm waiting for Dan to answer this question in firey, gory detail, but I'll just preview the answer with a YES! Definitely glue the outlet pipe back into the body of the petcock. I have a tiewrap around mine to prevent it from falling out.
DavidR.
[/quote]
I will have to check the outlet pipe a little more but i thought it was dripping out of the pipe. It didn't seem to be an external leak. When i connect the fuel line there isn't any drip. I am speaking of an 'internal' leak in the petcock itself. Is this possible and what are the options to repair it? Thanks
Sounds like the internals aren't sealing. You should be able to take the petcock apart and replace the o-ring and whatever else is in there...
Sorry, my bad. Your shut off o-ring had probably deteriorated. Replace it with a 5mm ID X 2mm Cross Section o-ring. You might want to also beef up the spring behind the diaphragm. Take the one that's currently in the petcock to the hardware store and find a slightly stiffer replacement. Don't go too much stronger, or the vacuum might not open it.
And while you've got the tank off, check the tightness of the outlet just for the heck of it. Tugging on the fuel hose tends to loosen it. Put a tiewrap around it anyway.
DavidR.
Quote from: SlowOldGuy on September 03, 2009, 08:22:10 PM
Sorry, my bad. Your shut off o-ring had probably deteriorated. Replace it with a 5mm ID X 2mm Cross Section o-ring.
DavidR.
Any ideas where to find a metric O-ring thats is of good quality. I don't trust Harbor Freight with there quality, I know they sell metric oring kits.
How do i get to the shut off o-ring/spring? The petcock looked liked it was riveted. Do i need to drill and replace with bolts? If you could please give me a little more info on the repair process I would appreciate it. Thanks
Ozz
Local ACE Hardware should have metric o-rings.
Remove the petcock and you should see (2?) screws that hold the diaphragm assembly together. Remove the screws and GENTLY pry the diaphragm cover open. You will remove the spring, and the diaphragm/plunger assembly. Replace the o-ring on the diaphragm plunger, install the new spring, and carefully reassemble.
Remember to check the fuel outlet for tightness adn install a tiewrap.
DavidR.
Hello folks,
My '89 has developed this issue. :shok: However my idle will creep back up to 2K no matter what I do. :scratch_one-s_head: Anything different that I should be looking for than what I have read in the thread so far? Thanks,
james
Quote from: SlowOldGuy on September 04, 2009, 07:08:49 PM
Local ACE Hardware should have metric o-rings.
Remove the petcock and you should see (2?) screws that hold the diaphragm assembly together. Remove the screws and GENTLY pry the diaphragm cover open.
DavidR.
Thanks David!
Finally took a some time away from the bug project to get this sorted out. :mad: Found a split in the vacuum hose connected to the #2 carb just before it connects to the restrictor. Cut the hose back reconnected, idle settled back to normal. :good2: While I had things open I resynched the carbs. They were only slightly out and it's been over 2 years since done last. I also repaired a broken scoop tab and found that my collector is broken where the #3 head pipe attaches. It's just floating in the collector opening. I begin looking for a replacement starting, well, now. :dash2:
Also a huge THANK YOU :yahoo: to the contributors to this thread for the suggestions on what to look for. :drinks:
Quote from: jamesearthdrum on September 26, 2009, 12:20:59 PM
Finally took a some time away from the bug project to get this sorted out. :mad: Found a split in the vacuum hose connected to the #2 carb just before it connects to the restrictor. Cut the hose back reconnected, idle settled back to normal.
Glad you found the problem.
Once again (for anyone having a similar problem), the only way an engine will increase it's idle speed is if it's getting air from somewhere. You can't dump extra fuel into the intake and get more speed, it takes extra air!
DavidR.