Hello, I recently bought an 86 fj1200 which had a hesitation on accell from stop unless choke was slightly pulled. Even then it sputtered and bogged unless I throttled it and then it would come alive. Rough idle with backfires thru exhaust. Drained fuel tank and found fuel breaking down. Removed carbs and found jelled fuel in bowls. I used Carb cleaner and light air pressure to clean any ports and fuel pick up tube to bottom of bowl, I did not take anything apart or adjust. I replaced fuel hose from tank to split off. I also replaced plugs. After reassembly the bike barely runs. Ran OK at first with a slight bog on take off but had to walk bike back after 3 mile ride. Feels like it ran out of gas. Will start but has very little if any throttle responce. Stalls on any type of accell. Low choppy idle. I inspected hoses to air box and intakes. All good. Any ideas? I definitely feel its a fuel issue or lack of. Plenty of volume thru hose to carbs. Same problem with fuel tank cap open. Thanks for any help, Rob.
its very common for people to replace the fuel line from the gas tank to the carbs and leave the line a bit too long.
it will cause the line to kink once the tank is bolted back down ... making the carbs run out of fuel.
also it would be best to thorougly clean the carbs and all jets.... just rinsing out the float bowl is not going to be good enough.
there is a great carb cleaning/tuning doc right here.....
http://www.fjowners.com/index.php?topic=655.0 (http://www.fjowners.com/index.php?topic=655.0)
KOokaloo!
Yep, +1 what Frank said, a pinched fuel line.
On the gravity fed FJ's ('84-'87) fuel line routing is most important.
There should be a diagram on your air box showing the correct route.
If you don't have this diagram, let me try to explain: As the fuel line leaves the tank petcock, this line should run *under* the two branch lines which feed each pair of carbs. It seems weird, but when the tank is installed the line will route properly.
What happens if you run the fuel line above the two branch lines is this, it forms a kink in the fuel line. When the bike is cold (on start up) the fuel line is still hard and it lets a little bit of gas flow thru to the carbs and the bike runs.... but when the bike warms up and things get hot under the tank, the fuel line softens up and the kink closes off the fuel flow. If you replaced the single fuel line before the 'Y' then chances are the new harder fuel line is pressing down on one or both of the softer oem Yamaha fuel lines.
Again, run this single fuel line *under* the two branch lines and I suspect all will be well.
It's a right of passage for the owners of the older gravity fed FJ's to figure this out.... It has happened to a lot of us.
Also check your vacuum line which opens the petcock, the same thing could be happening to the vacuum line. A pinched vacuum line will close off the petcock. This happens only rarely, most often it is the fuel line that's the culprit.
If pinched fuel line(s) are not the problem (doubtful) then it's time to once again remove your carbs, disassemble them, and properly clean them. Pay particular attention to all those little holes on the main jet nozzles (aka emulsion tubes) and your pilot jets and tiny air jets.
Oh yea, safety wire that petcock while you are under there! http://www.fjowners.com/index.php?topic=3265.0 (http://www.fjowners.com/index.php?topic=3265.0)
Hope this helps. Pat
Hi weber1
+1 to what Frank and Pat said.My oem fuel lines were in pretty poor condition and I replaced them with thicker 5/8 stuff from my local auto shop and off course ended up with kinking problems.I found this thread which cured my kinking woes.Getting rid of the oem airbox and fitting uni pod filters also helps.(more room and easy carb servicing :biggrin:)Thanks mr blackstock...... :good:
http://www.fjowners.com/index.php?topic=4411.msg38941#msg38941 (http://www.fjowners.com/index.php?topic=4411.msg38941#msg38941)
Hope this helps
Cheers :drinks:
Jeff P
An interesting item I found on my parts bike was the fuel lines. The previous owner used copper tubing for the curved bend. So off of the T-joint he had a small piece of hose that lead into a curved copper tube that wound around that bracket and then another piece of hose clamped onto the end that would attach to the petcock.
It looked hokey but it I like the idea after all the issues that I've had in this area ( not only kinking but cracks too that go undetected ).
Thanks guys, I will check all the things mentioned out. I did replace the fuel line with a harder line and cut to same length but on reinspect i found it kinked and not routed as mentioned. I will remove the carbs this week and do a thorough cleaning. I did not notice any vacuum line to petcock or fitting for one. I removed petcock assembly and inspected screen, all good. The amount of responses and the knowledge shown is greatly appreciated, Thanks. Rob.
On the petcock issue, it may have been replaced. It's just a basic 3 position valve, off-reserve and on. Also,after I get the bike running correctly I will be changing fork seals. Until then, is there a way to check oil levels and add if needed add without removing front suspension? It feels strange asking asking what are probably basic questions. I have been in my field for 25 years as a senior tech with Ford Motor Co. but this is a new area for me. Used to ride alot as a kid and when I lived in Florida. Now that I'm older and a few of my friends ride I decided to go for what I like instead of the typical Harley guys my age are buying. I wanted aircooled inline 4 long low and mean. Thanks again.
Weber1,
The fork oil height (or amount of trapped air) is one of the variables used to adjust fork action.
While the manual gives you only a volume measurement for fork oil, the better and much easier way is to set fork oil height. This is with the springs (and preload spacers) out and the fork fully compressed.
Standard is about 160mm from the top of the fork tube. Having the oil higher will give you a more rising spring rate as the fork approaches bottoming due to the trapped air being compressed. I have my fork set at 130mm, but that is personal pref.
You can check fork oil height with the fork in place, but you'll have to remove the handle bars, and the fork caps to remove the springs and preload spacers. So, find a way to support the front of the engine first. Then remove the bars, caps, spacers, and springs. Have a helper raise the front wheel fully and use a dipstick to measure the distance from the top of each fork tube to the oil.
A 20mm hypodermic syringe with a tube on the tip and an O-ring around the body can be used to set the height quickly and accurately.
HTH,
Arnie
Thanks Arnie, I noticed alittle oil on left side fork. Suspension feels alittle soft to me. I will do it all the right way when I replace the seals. Back to the driveability issue. I put the right hose on and routed it the correct way. Plenty of fuel going to carbs now. After letting it warm up for a few minutes I have a dead spot on an accel off of idle,will stall. I have to feather up the throttle. On road test it goes from nothing to warp drive, no real medium. I am taking the carbs off tonight to thoroughly clean them. Is there anything else I should look at while I am there? Thanks, Rob.
Quote from: Arnie on February 22, 2012, 08:32:57 AM
The fork oil height (or amount of trapped air) is one of the variables used to adjust fork action.
While the manual gives you only a volume measurement for fork oil, the better and much easier way is to set fork oil height. This is with the springs (and preload spacers) out and the fork fully compressed.
Standard is about 160mm from the top of the fork tube. Having the oil higher will give you a more rising spring rate as the fork approaches bottoming due to the trapped air being compressed. I have my fork set at 130mm, but that is personal pref.
You can check fork oil height with the fork in place, but you'll have to remove the handle bars, and the fork caps to remove the springs and preload spacers. So, find a way to support the front of the engine first. Then remove the bars, caps, spacers, and springs. Have a helper raise the front wheel fully and use a dipstick to measure the distance from the top of each fork tube to the oil.
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.
As for the latest in drivability, clean the carbs quite well before you start making too many adjustments. If it keeps doing this most recent behavior after they're known to be good and clean, you could try adjusting the float height / fuel level a bit. Also before making carb adjustments, do check the stupid easy stuff, like the condition of the spark plugs and air filter(s).
Will do. Hopefully the cleaning will do the trick. Plugs are new as is the airfilter. Thanks.
when you pull the carbs apart dont forget to remove the emulsion tubes and clean all the little holes out (the main jets screw into the emulsion tubes)
a proper balance (synch) is also going to be required for the carbs after you clean them.
KOokaloo!
I cleaned the carbs last night, jets and float screens. I only saw one pin hole in emulsion tubes. Cleaned every hole, port, you name it. I installed the carbs with each adjustment screw at 3 turns from fully seated. After warm up the bike runs 90% better. It still has what feels like a miss or stumble on initial snap of throttle. I am going to sink carbs friday. I did not feel comfortable trying to remove the tubes so I cleaned them best I could. I would like to know what the spark plug gap should be set at and if, because of age, should ignition wires be changed? Thanks, Rob.
Weber. the emulsion tubes are a piece of cake to remove. After you have the tops & float bowls removed, along with the slides. Loosen the main jets 1-1/5 turns, then tap them. This will force the tubes up from the carb body. Reach inside the carb throat & remove the tube. Clean until spotless, reassemble. Also make 100% sure the pilot system is clean. I use carb cleaner, sprayed into the air jet in the inlet side of the carb, then remove the adjustment screw, and spray some more, making sure that the cleaner exits from the air jet, the pilot jet and then the downstream hole in the carb body (after the throttle plate). Next, make sure the pilot jet is 100% clear. I had 1 jet that was perhaps 10-20% blocked, and it effected the running. Reassemble and sync, adjust mixture and you're done.
Well, I will probably pull carbs again Saturday and clean the emulsion tubes as recommended. Runs alot whole lot better already, just don't think that hesitation is safe. Thanks for all the advice.
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
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.
As Ed said, be VERY sure the idle circuit and components are clean. You should also check the fuel/float level.
DavidR.
Quote from: andyb on February 22, 2012, 09:53:48 AM
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 :drinks:
Jeff P
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.
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 :good2:
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!
Quote from: weber1 on February 25, 2012, 05:18:25 PMAlso 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
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.
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
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.
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.
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!
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?
You sir, need a shop manual. :)
Probably the most important thing in the toolbox!
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.
ok- here we go. Put new caps on wires. cut back wires about 1/4 inch for fresh wire and now have strong spark on all four. What I have now is a fuel concern. The bike runs so rich it misses and smokes. Great. AND-I noticed a small amount of paint suddenly missing from forward lower corner of tank,thought maybe I scratched it. when I was cleaning it for touch up I saw it was wet and leaks fuel. At this point I want to take bike and drop it in the bay. Carbs were spotless with new emulsion tubes and correct float levels. believe it is only one carb and probably #4. The tank was sealed once so I have to look into that or another tank. Really ashame because the bike is absolutely beautiful but I have enough projects and am losing confidence in the bike for fear I'm always gonna break down.
Quote from: weber1 on March 09, 2012, 11:54:01 AM
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.
Then...
Quote from: weber1 on March 11, 2012, 05:29:41 PM
ok- here we go. Put new caps on wires. cut back wires about 1/4 inch for fresh wire and now have strong spark on all four. What I have now is a fuel concern. The bike runs so rich it misses and smokes....... Carbs were spotless with new emulsion tubes and correct float levels. believe it is only one carb and probably #4........
Rob, what the hell is going on? Is all this is happening to the same bike, or do you have 2 different bikes?
You get it almost dialed in.... and then put on new plug caps... and this shit happens??? I'm getting pissed off just reading your posts.
I can't imagine what you are going thru.... Pat
HAHA! Same bike Pat. Tonight I will take tank off and have it sealed by a guy who does the diesel truck tanks for us. Then I will drop it off at the body shop we use to have them reshoot the top and touch up the lower corner. I think I missed diagnosed the spark concern. I think one carb has an issue and caused the miss, possibly causing the spark issue when I pulled the wire off of the plugs while running to find which cylinder was dropping. I am going to pull carbs again and see if anything changed. Maybe debris in float needle seat. It's a pretty basic engine and carb set-up so shouldn't be to difficult. The bike sat and I think the guy who had it had a hack for a mechanic. I'll get it.
I feel your pain! Get the tank taken care of before you keep chasing the same gremilins through your carbs. As long as the tank has that much rust and crap in it, it won't matter how much you clean the carbs - you're still going to be getting debris into them - even with a filter it seems!
I'll bet once you get the tank right, the rest will fall in line with just a thorough cleaning and adjusting.
Good luck!
Thanks-spoke to guy who is going to do the tank. He says may be a concern since it was sealed once before. He may do an external repair then off to the body shop. I never noticed any rust in carbs. Maybe a piece of sealer, won't know untill I get into carbs. Question-what would be the sympton if a diaphram in a carb went bad? I inspected all 4 and they looked good under light. Maybe I left something loose, who knows. On the bright side I can R&R the carbs real fast now!
With as many times as you have had those carbs off, are you still struggling with the oem air box or have you converted over to Unipods?
R&R'ing the carbs are a snap with Unipods.
Something is getting into those clean carbs, so your tank may be the culprit. Let us know what you find.
Quote from: racerman_27410 on March 09, 2012, 02:12:07 PM
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.
You have sync'ed those carbs...right?
Hey guys, took carbs off after determining #4 carb is pouring fuel into cylinder. disassembled said carb and found the float needle seat brass housing cracked. Any body ever seen this? Well, I will be replacing that. Dropped tank off for sealing then repaint. Very possible small crack in carb was causing problems for awhile and finally expanded and made itself clear. Does this part come in a rebuild kit? Thanks for all the inputs, Rob.
The float needle seat, you mean?
Looks like this?
(http://fjowners.com/gallery/2/medium_10_18_05_11_2_06_15_5.jpeg)
There's one in this (http://www.rpmracingca.com/proddetail.asp?prod=Carb%3ARebuildkit2&cat=24) kit, and they're individually available like this (http://www.rpmracingca.com/proddetail.asp?prod=Carb%3AFloatValveG&cat=24), also.
Yep-however,on further inspection it was not a crack, a small piece of debris stuck to outside. cleaned and when i picked up assembly found idle jet on bench! Apparently I left it loose and it fell out. So I am going to climb out of my skin and kick my own ass tonight. I took float balls off of all carbs and double checked for debris and correct assembly. No more working on bike at 1am. Thanks for all the inputs, Rob.
bowls that is.
At this stage, it is perfectly acceptable to call them float balls.......sync those carbs.
Will do. I have the tank being serviced now at the Radiator shop. Then off to paint. I may redo the forks in the meanwhile. I went to a Kawi-Yami dealer and looked at the new Ninja while I was there, just to kill time. I couldn't get into it-the bike is too short from front to rear. Almost all were. Felt like I was on a unicycle!
The Ninja-1000 is a nice bike, but it's nothing more than the Z-1000 with full bodywork. The seat-to-peg distance is too cramped for me, but otherwise a nice bike.
DavidR.
A ninja 1000 is only an inch shorter than an FJ. Not much in it, there.
It's remarkably silly looking, overprice, and for many other reasons not something I'd want, but stubby isn't the word.
Only an inch? seems shorter and you're right about the leg position. I'm 6'1" and they were cramped. The bike is considered a sport touring. I don't see it. Still stay it seems short, Like riding a pumped up mosquito! Also, does anybody have a fuel sending unit they wanna sell?
Picked up the tank and the repair was minimal, touch up was a breeze and the body shop wasn't needed. Put carbs on and ran it. Smoked like a cropduster because of fuel in exhast and rings in #4 cylinder being washed out. After a ride around the block the bike was an absolute blast to ride! The acceleration was insane and the turns were alot of fun. Now I know why you guys are passionate about these machines. Love it.
Good deal Rob! Kudos for sticking with the problem and working through it.
Be sure to let that bike warm up, and the oil get to 160+ before you flog her. It takes longer than you think.
Put many a mile on her this spring. The more you ride her the better she will run. Cheers!
Thanks Pat. I did notice that it does take longer then I thought to get the bike to the best operating temp.This summer I am going to enjoy it and next fall do a strip and restore. One of my best friends' has a dyna glide and took my Fj for a spin and had a blast. Next are the fork springs.