My FJ is got what I think is a genuine carburetor issue, but I'd like a couple of second opinions before I tear em' down.
Mid range seems to be bucking me all over the place while going down the road approx 45-60 mph. If I roll on the throttle, it smooths out and acceleration it good, but still with an occasional stutter. It seems the worst when I'm trying to maintain an even speed, while not increasing or decreasing the throttle input more than a little either way. My guess is I have a dirty carb.
I synced them about 2 months ago and everything was dead on at that time. Fuel filter, plugs, cables inspected, air filter cleaned (K&N), chain cleaned/tensioned, drive gears checked and oil/filter all done within last month (spring tune-up!). I even tried a 1/2 bottle of Techron to see if it would help, but no change.
Opinions? Special areas to check first or things to look for when taking carbs apart? (Already have all the info from this forum on carb rebuild, parts and cautions)
Thanks in advance.
It sounds like you may have a problem with low voltage or no voltage to the ignition coils. Pull the tank and check the voltage at the ignition coils with a DVOM. If its lower then the voltage at the battery, install a power relay. You need to clean the contacts in the kill switch too. They are prone to corrosion.
This is a good how-to on the relay.
http://www.wgcarbs.com//index.php?option=com_content&task=view&id=12&Itemid=26 (http://www.wgcarbs.com//index.php?option=com_content&task=view&id=12&Itemid=26)
If there were "no voltage to the coils" wouldn't the bike just cut off? Low voltage would still be a likely issue if it idles and acceleration is fairly smooth? Plugs seem to be burning excellent is the confusing thing....
Quote from: Scooterbob on April 01, 2011, 01:37:53 PM
If there were "no voltage to the coils" wouldn't the bike just cut off?
Yes, this type of problem normally presents as intermittent. Engine vibration can cause the problem to come and go.
Low voltage would still be a likely issue if it idles and acceleration is fairly smooth?
Yes, the only way to know is to check the voltage at the coil.
Plugs seem to be burning excellent is the confusing thing....
Yes, if the plugs look good, it makes me think that the carbs are good too. Are the clamps on the rubber intake manifolds tight? Are the manifolds fresh?
Clamps are tight and intakes are in good condition. I will know voltages later tonight or early tomorrow morning.
Other opinions?
Ok. Tested at coil plugs this morning. Got 10 volts at each. Battery reads 12.9. Looks like a relay wouldn't hurt. I will install later today.
Think I should even bother cracking open the carbs at this point? Fairly certain they could use a cleaning but fixing stutter issue is my priority.
It wouldn't hurt, just to see what inside looks like. They can't be to clean.
But does sound like your coil voltage, now I will have to go check mine. Great thanks. :rofl2:
Bob W
Sorry to start a coil voltage riot. :greeting:
Since the connected link shows only one relay, would it be best to install two separate ones? Wasn't there a write-up somewhere for our bikes specifically for this?
Quote from: Scooterbob on April 02, 2011, 09:49:31 AM
Sorry to start a coil voltage riot. :greeting:
Since the connected link shows only one relay, would it be best to install two separate ones? Wasn't there a write-up somewhere for our bikes specifically for this?
Just read this!
http://www.wgcarbs.com//index.php?option=com_content&task=view&id=12&Itemid=26 (http://www.wgcarbs.com//index.php?option=com_content&task=view&id=12&Itemid=26)
I did! Did you read my questions?
Why in the world would you think that 2 relays are better then 1?
Bob, I think you are recalling the headlight relays where you need 2 separate relays, one for low beam and one for high beam.
You only need one coil relay which supplies power to both coils. Jon's link shows 1 relay for 2 coils.
However if you have not done the headlight relay mod yet (it's highly recommended) why not kill 2 birds with one stone? Do all the relays at once, all three. That way you just add a third relay to your (unswitched) 12v home run, to power your coils. You need 3 relays for this mod. You can not use the power taps off your 2 headlight relays to power your coils because, do you notice when you thumb the starter button your headlight shuts off? You would lose power to your coils if you used your headlight relays when you pushed your starter.
Clear as mud?
THAT'S the mod I was thinking of! Thanks for helping me with my cerebral rectalitis problem (head in ass).
I will proceed with doing all three as you mentioned.
Thx again all.
Quote from: JCainFJ on April 02, 2011, 02:01:00 PM
Why in the world would you think that 2 relays are better then 1?
I think there is a write up/ post about adding a relay to the coils awhile back. I think Bill(the fan) may have posted it. I am planning on do this mod and cleaning up all of my past relays and wires I have done.
LA Mike
Quote from: LA Mike on April 02, 2011, 02:30:26 PM
I think there is a write up/ post about adding a relay to the coils awhile back. I think Bill(the fan) may have posted it........
Yep, it's in the Files section under Modifications
Problem. Got carbs all done finally and now the damn fuel pump isn't getting voltage! Manual says "check voltage at back of fuel pump relay on Red/white. That's good. Reconnected harness to relay and still nothing on Black/blue wire going from relay to the pump. Grounds good and checked every plug possible. Even tried battery straight to pump and pump is good.
Ideas? I cannot even see if my carb cleaning helped anything...... :sorry:
Ok, day number two (and final day because I must drive this to work tomorrow). Still no fuel pump cycle. Checked as many connections as possible. Also threw the battery on the charger overnight, so I can start fresh again.
The only thing I have done between when the pump cycled fine and now is clean the carbs and change some gauge lights. Didn't even get to putting the relay on the coil circuit yet. Any ideas as to where to check again?
SOMEONE PLEASE HELP!!! :cray:
Killswitch, sidestand switch, etc.
Unplugged harness connections, or corroded/crappy connections. No power at the pump itself? Go from the pump and work backwards... Wonder if you forgot something when you had the dash to bits?
Turn the key on, what lights up, and where do you have and not have power? Got a wiring diagram to work from?
Killswitch, sidestand switch both check good from what I can tell.
Turning on the the key lights up my green neutral light and all dash lights, headlight, taillights come on normally. Starter turns over smooth.
No power at the pump itself, correct. Have good voltage going in to the fuel pump relay, but nothing coming out on the blue wire that goes directly to the pump (when key is turned on). Possible that I could have bumped something when doing the dash lights, but I only took off the speedo cable and two main connectors to the gauges when I worked in that area. Those are all reconnected good, but I will check again.
Yes, I have a diagram to work from, and the manual tells how to very basically check this problem. Says I should have 12 volts at red/white wire on harness of pump relay (and I do). Then it says to plug harness back in to relay and probe blue wire from back of it to check for voltage when key first turned on (I have nothing, like I mentioned above). Checked all connections in the area, but still nothing.......
Bob, If you have voltage going to the fuel pump relay and no voltage at the pump the fuel pump relay might be bad. Since you say the pump works fine when connected to a 12 volt power source the relay is the only item sending voltage to the pump from the wiring harness.
Eric M
Just found something interesting. When checking connections at the pump relay, I found that the ground wire shorts to the positive......I think. Let me explain.
When I put my meter on the "beep" ohms setting, it shows that I have connectivity from the black wire on the back of the relay harness (unplugged) to the negetive terminal on the battery. Ok, good. But as soon as I turn on the ignition switch, it drops out. Next, I took off the negative terminal on the battery. I then connected meter between black wire on back of relay harness (ground) and the other lead to the bare negative battery terminal (disconnecteD) and I still show connectivity. Odd.
Soooo, my thoughts are to (for now) take the black wire from the relay harness and then run a new wire from the negative ground spot to the connector where I removed the black wire. Basically reground the relay, but not using the original wire. Hopefully that will shed some more light, BUT NOT SPARKS!!!! :biggrin:
Does any of that make sense?
IT'S ALIVE!!!! :yahoo:
Traced back to the reserve switch. Found that was what was shorting everything out. Flipped and wiggled that switch a couple of times, and fuel pump fired right up. Switch has always been kinda fragile looking and half hanging on. Could use a new/good condition one, but for now I will see how I can bypass or stabilize this switch, since I've never had to use it anyhow.
Thanks all for the help and input. If nothing more, confidence that it can be done is all I really needed I suppose. I humbly grovel at the forums' feet.
Way to go Bob. I wonder if the dad gum fuel reserve switch was the cause of your bucking?
This fuel reserve switch is a good item to add to the list of culprits to check, after the usual sidestand switch, etc, etc.
Congratulations on fixing it.
Now you can go to work. So even when you win, you kinda lose... :)
Good Work!
Quote from: Scooterbob on April 03, 2011, 10:12:41 AM
IT'S ALIVE!!!! :yahoo:
Traced back to the reserve switch. Found that was what was shorting everything out.
Quote from: Pat Conlon on April 03, 2011, 10:37:57 AM
Way to go Bob. I wonder if the dad gum fuel reserve switch was the cause of your bucking?
Although my throttle response is waaaaay better now, I am almost positive that the bucking was coming from this switch cutting my fuel pump off and on (while vibrating) when going down the road. Now I know. Definitely a good thing to check in the future. Would have been nice if I hadn't had to strip the entire bike naked to figure it out though.
Quote from: andyb on April 03, 2011, 10:52:49 AM
Congratulations on fixing it.
Now you can go to work. So even when you win, you kinda lose... :)
Got no problems with going to work. Keeps the moto wheels turning. :biggrin:
Quote from: Pat Conlon on April 03, 2011, 10:37:57 AM
This fuel reserve switch is a good item to add to the list of culprits to check, after the usual sidestand switch, etc, etc.
Yeah, and it is a good thing to immediately disable upon getting your FJ. I know a lot of us have done that. I don't need my motorcycle cutting off my fuel mid-corner to remind me that I'm getting low on gas - but that's just me!
It also makes a nice switch for something else - mine controls a cigarette lighter socket which turns my GPS on and off and also powers on a voltmeter for the battery.
How did you bypass? Just unplugged it?
Dunno Bob.
Just do a continuity test on the reserve switch when the switch is set in the reserve mode. See if the switch is open or closed. That'll tell ya if you just need to:
1) disconnect the switch or 2) disconnect the switch and tie the wire leads together. You want the fuel pump in the reserve mode 100% of the time.
Marsh, we know that there are times that, lifting off the throttle is not a good thing to do.....I never thought of the stumble/loss of power when the tank goes on reserve...yea, mid corner in a 80mph sweeper on Hwy 36. That would suck. I'm gonna bypass the reserve switch on my '92 asap. Thanks amigo!
Photos for all who agreed that carbs may have been dirty. Relay mod going on tonight.
(http://fjowners.com/gallery/2/661_04_04_11_12_08_41.jpeg)
Before teardown.
(http://fjowners.com/gallery/2/661_04_04_11_12_07_20_1.jpeg)
Side view of exterior dirt.
(http://fjowners.com/gallery/2/661_04_04_11_12_11_39.jpeg)
Dirty bowl!
(http://fjowners.com/gallery/2/661_04_04_11_12_12_09.jpeg)
Just a little dirt.....
(http://fjowners.com/gallery/2/661_04_04_11_12_12_53.jpeg)
Don't forget these little guys.
Wow, those look nasty.
Just a little. But they all good now. :good:
Its amazing the amount of crud that comes out of a gas tank and accumulates in the carbs and the bike still runs, isn't it? I just replaced my tank with a clean one and you should have seen the crud and rust on the sending unit. I was afraid to look inside closer. All better now though. :good2:
Your FJ is gonna love you for cleaning the nasties out of there.
Cheers...Jake
Just finished the relay install on the coils. Even synced the carbs again. Holy Batshit Batman!!! What a difference!
Now I gotta do the clutch spring mod, cuz it slips like a mutha-lover with all the new torque. But not complaining. :good:
If you can get the oil light to come on during hard acceleration then it will be tuned right. :good2:
you are on track with the clutch spring ,almost there.
Seems to be one ongoing detail I cannot figure out though.
My idle is set at 1000 and the "blip" test show the rpm drops correctly, but when I drive it continually likes to hange around 2000-2500 and then slowly come down. Sometimes it stays there until I bring it down by holding the brake and letting the clutch out a little. Then it idles fine. Also, when I give full throttle around 5000 rpm it pings a little.
Cable has free travel and has the recommended 5mm of slack. Mixture screws at 2 1/2 turns and carbs balanced beautiful with carbtune guage.
I was thinking maybe too rich, but would that explain the ping and throttle hanging? All else seems really good and power is excellent.
Ideas?
Bob, sounds like a vacuum leak that pops up when the bike is hot. I assume that there are no leaks (cracks) on the carb boots.
Check the o rings on the idle mixture screws. When you pulled the idle mixture screws out for cleaning did you put new o rings on, along with remembering to put the little washers and springs back on the needles, before you put the needles back in the carb bodies?
Now that the carbs are clean, review for us your carb settings:
Idle mixture screws: How many turns out?____________
Main jet #:__________
Pilot jet #:__________
Needle clip position (from the top):__________
I did not put new o-rings on the mixture screws. Could not find them in a timely manner. But I did inspect the old ones and put the washers/springs back in correctly.
Mixture screws set at 2 1/2 out. All jets are the stock ones that were already in there. I merely cleaned everything really good and changed the other o-rings. Boots all looked good, but are old. Did not touch clip. Only washed that part (diaphragm assembly) with warm soapy water and inspected.
if you are running a 4/1 pipe you may want to go out with those pilot screws another turn or so and give that a try.
KOokaloo!
Quote from: racerman_27410 on April 05, 2011, 09:11:56 PM
if you are running a 4/1 pipe you may want to go out with those pilot screws another turn or so and give that a try.
KOokaloo!
Does a lean mixture cause the hanging high idle? I thought it would be the opposite.
I'm running totally stock system.
Update: Adjusted mixture screws last night to 3 1/4 turns out. It seems to have fixed the hanging rpm problem, but need more driving. Since this morning was a FREEZING 62 degrees coming to work, I'm not sure if it will act different on my 80 degree ride home in stop and go traffic. I will let you know.
By the time it gets to 62 degrees, I've started using my mesh gear.
Quote from: carsick on April 06, 2011, 09:49:53 AM
By the time it gets to 62 degrees, I've started using my mesh gear.
The mere thought of you in all "mesh" is a little disturbing. :bad:
Ha ha ha.
Quote from: Scooterbob on April 06, 2011, 10:13:48 AM
Quote from: carsick on April 06, 2011, 09:49:53 AM
By the time it gets to 62 degrees, I've started using my mesh gear.
The mere thought of you in all "mesh" is a little disturbing. :bad:
Ha ha ha.
Oh no, I don't wear ALL mesh. Just the chaps.
Quote from: carsick on April 06, 2011, 08:36:15 PM
Quote from: Scooterbob on April 06, 2011, 10:13:48 AM
Quote from: carsick on April 06, 2011, 09:49:53 AM
By the time it gets to 62 degrees, I've started using my mesh gear.
The mere thought of you in all "mesh" is a little disturbing. :bad:
Ha ha ha.
Oh no, I don't wear ALL mesh. Just the chaps.
Do they have "Harley-Davidson" stamped on them? :lol:
No, that would be redundant since the prison tat reads the same. I'm dying here Bob, it snowed last night and again today. But good job on the carbs and switch diagnosis!
Just thought I'd post a little sunshine for ya.
(http://fjowners.com/gallery/2/661_07_04_11_5_57_56.png)