I have a 1989 fj 1200 I changed the plugs a couple weeks ago and # 4 plug was black but not wet. I did a compression test and all were 150-160 so I cleaned the carbs put new needle and seats and new pilots and mains synced the carbs. Ran it 150 miles still not perfect so I pulled the plugs # 4 black I checked the others are fine. I played withe the fuel screws the rest are at 2.5 turns #4 after a half a turn it gets black. Ichecked for spark it looks ok. I cleaned the conections on the coil no help. I pulled the plug wire to each cylinder and 1 2 and 3 the rpm dropped but it didnt change much on number 4. I would appreciate any help I'm running out of ideas thanks Flick 250
there could be an issue with the oil control rings on that cylinder.... wouldnt affect compression but could be letting oil get up into the cylinder.
how often do you have to add oil? is the exhaust sooty/wet?
KOokaloo!
First I would put a new spark plug in and make sure the ign. wire and plug cap are in spec. Is the spark produced as good as the in the other cyl ?
Then I would pull the #4 carb off and really clean it, check everything... float height, choke plunger for a good seal, fuel inlet needle valve not binding, float not cracked or leaking, function check diaphragm for correct operation etc.. take your time and check everything. I think in the "files" section there is a real good write up with photo's on rebuilding the carbs.
As stated it could be a oil control ring. But hopefully its just a carb problem. Think simple... It seems natural to think or gravitate toward the most obscure or difficult/expensive solutions. I think its panic :). Black sooty plug = to much fuel, no or min spark, bad plug, oil getting into the combustion area ?
As preventive manit. if I pulled the carbs off I would pull the intakes off and replace the manifold "O" rings. They are cheap and after 20 plus years I would just do it. It is NOT causing your current problem but might prevent a future problem.
Things to think about :)
Ive put 600 miles on it since the oil change and it really hasnt changed much in the oil window. I think I'll try a new cap I'm off monday I'll go get one and try it I think they just unscrew and screw in I'll letyou know how it turns out
I checked the secondary checking between 1 and 4 I got 237 kohms I pulled the cap and cut the end and checked it and I got 23k I checked the cap and I got 10k checked the primary it was 1.9 after putting the cap back on the wire it was 33 I also checked 2 and 3 that was 34k I guess I need caps and plug wires should I get them from the dealer or somewhere else. Do the plug wires unscrew from the coil like the caps do. Thanks for all your help flick 250
The wires are just 7mm solid core wires, I get mine from my local NAPA store as they have it in bulk. They are glued into the coils and will come out with moderate pulling force. There is a needle down inside the coil that penetrates the wire when you reinstall.
Here are the Spark plug boots (http://www.rpmracingca.com/proddetail.asp?prod=Ignition%3ASPB)
You should switch #1 & #4 wires on the plugs and see if the problem moves to the #1 cylinder. If it does that confirms the secondary ignition system for that coil is having troubles.
If the problem does not move then you are back to carbs.
Randy - RPM
thanks randy I will go to napa monday and get those wires what is the right glue for putting them in thanks flick 250
Quote from: racerrad8 on August 11, 2012, 06:21:19 PM
The wires are just 7mm solid core wires, I get mine from my local NAPA store as they have it in bulk. They are glued into the coils and will come out with moderate pulling force. There is a needle down inside the coil that penetrates the wire when you reinstall.
Here are the Spark plug boots (http://www.rpmracingca.com/proddetail.asp?prod=Ignition%3ASPB)
You should switch #1 & #4 wires on the plugs and see if the problem moves to the #1 cylinder. If it does that confirms the secondary ignition system for that coil is having troubles.
If the problem does not move then you are back to carbs.
Randy - RPM
I agree with Randy. Before you spend the time and money do a quick test to verify. Although on an older, bike new wires and caps wouldn't hurt anything I have given some thought about it myself and I have no current problems. To many years working on airplanes.... Always seemed better to time change out certain items. Its embarrassing when they fail in flight :)
Anyone got a pic of these manifold orings?
Quote from: wakdady on August 13, 2012, 08:57:03 PM
Anyone got a pic of these manifold orings?
Sure, you need not look any further...
Intake Manifold O-Ring (http://www.rpmracingca.com/proddetail.asp?prod=Carb%3AIntakeO-Ring)
Randy - RPM
Oh yeah! I got those with my rebuild kit but I have no idea where they go!
Quote from: wakdady on August 13, 2012, 09:47:00 PM
Oh yeah! I got those with my rebuild kit but I have no idea where they go!
On the back side of the rubber intake manifolds between the head & manifold.
Randy - RPM
So I gotta remove those black boots to install them?
I gotta come see you in the next couple weeks randy. Watch a doin this weekend?
Quote from: wakdady on August 13, 2012, 09:52:17 PM
So I gotta remove those black boots to install them?
I gotta come see you in the next couple weeks randy. Watch a doin this weekend?
Yes, pull the heat shield & the allen bolts to remove the intakes.
I should be here, give me a call and let me know.
Randy - RPM
well i put new caps and plug wires I was pretty sure it would fix it but it didnt guess I'm going back in the carbs any suggestions could the float be sinking I put new needle and seats and new pilots and mains I thought they were really clean I took my time I guess I'm pretty bummed I thought for sure the wires and caps would fix it I did switch #4 and #1 the problem didnt switch
Youve got unmetered fuel seeping in from somewhere. Double check the needle seat o-rings, maybe you pinched the one on #4. You did install new o-rings, right? Do the upside down blow test to make sure they are not leaking.
Next check the float/fuel level. If you have some way to measure the float weight, compare them and see if one is somehow retaining fuel. Swap the #4 float to a different carb and see if it follows the float.
Make sure all the choke plungers are sealing. If you blow into the small oval port on the air filter side of the carb, it should raise the slide and slowly leak down. If the choke plunger is leaking, the pressure will leak down faster than the other carbs.
That all I got. Good luck and report progress.
DavidR.
I've been having this issue for a while. Two plugs oily and shitty. Float bowls are at 22mm and everything in the Carb is brand spanking new! I'm beginning to think its mechanical in the motor itself. Won't idle but I'll rev fine after about 2k
Quote from: wakdady on August 15, 2012, 08:47:22 PM
I've been having this issue for a while. Two plugs oily and shitty. Float bowls are at 22mm and everything in the Carb is brand spanking new! I'm beginning to think its mechanical in the motor itself. Won't idle but I'll rev fine after about 2k
"Oily and shitty"? Or sooty ? Are you consumming any more oil than normal ? What is your exhaust color ? (not a real good indicator by the way) are your muffler tips oily or sooty ? How's the plug smell ? Gas or oil ? Get a piece of white paper and smear some of that material off and see if its oily or sooty. I am not sure any of this will help but....
Just for grins, take the seat off and check out the choke rod mech and what you can see of the choke plungers, activate the the chock knob make sure #4 is entering and pulling out the same as the others. You will notice that the brass part of the plunger probably has a lot of wear where it connects to the choke rod via a small "forked" bracket. (Randy will probably have to start stocking choke plungers someday from what I have seen), Is the small forked bracket on the rod tight? I think its an allen screw into a small detent on the choke rod. It's probably ok but hey its an easy check.
After that I would pull the carbs and do more checking.
Blow test the diaphragms. If there is a bad leak then take a real hard look at the choke plunger and diaphragm seal.
Turn the carb upside down and blow into the fuel inlet ( I would think if it was leaking you would notice fuel dripping under the bike out of the overflow hose) but better to check. You are aware that there are 2 different fuel inlet needle and seat valves ? One I think for gravity feed and one for pressurized fuel. Look in RPM online catalog. Make sure the float is real free and no binding. Jet snug, needle clip/washer/plastic spacer in correct position etc, etc. Details....
I don't know if any of this will help but its just a machine and you will get it trimmed out.
Oh, back at the spark plug, did you actually see a good spark at the plug ?? If you have a real good friend have him hold on to it while you crank over the engine :) Give him (or her) a few drinks before hand :)). OSHA would most likely have you put a lot of padding around just for safety's sake...... Better safe than sorry... :sarcastic:
Quote from: wakdady on August 15, 2012, 08:47:22 PM
I've been having this issue for a while...
Henry, Henry, Henry... :unknown:
Quote from: wakdady on August 13, 2012, 09:52:17 PM
I gotta come see you in the next couple weeks randy. Watch a doin this weekend?
Give me a call, this weekend can work for me.
Randy - RPM
Quote from: flick250 on August 15, 2012, 06:43:36 PM
...I did switch #4 and #1 the problem didnt switch
That means you either have a carb or mechanical engine issue causing the plug reading.
Randy - RPM
Changed the #3 and #4 floats and re- synced the carbs runs good now no more sooty plug. Thanks for all the help. Just ordered new handle bars from speigler shuld be here tues cant wait. Again thanks for all the help Flick250
Glad to hear you located the problem :). Thanks for the update. Always nice to read the last page of a mystery ! In the end the problem was simple. Do you think the float was sticking or was it adjustment ?