Hi! This all started in another post but I think it's time for a new one.
I have (or had) perfectly running 1985 FJ. Then to fix a leaking carb I changed float valves and seats, at first only in that one but then in all four. And I messed a bit with floats to set them according to manual. I set the mixture screws to 2 turns out and floats to 21.5 mm. It starts good on full choke and idles but when I open the throttle it first stumbles then revs. And a backfire follows. When I constantly rev it around 2-3 k RPMs it backfires constantly through the exhasut. Searching here told me it is lean so I turned mix. screws until 3 turns out, same thing. Also tried lowering the float to as low as 20 mm and getting it higher to 24-25. Same thing. All jets are clean, carbs are clean. This is killing me.
One of the fuel pilot jets is a bit messed up, though. But orifice is intact, only top part of it where screwdriver slot is is bad. Do you think that could be the issue? I also changed the fuel and vacuum lines. Hoses have the same inner diameter but are a bit different looking from the outside. I really don't think that is an issue.
Float valves and seats are from Keyster and they do look a bit different in hight, but measuring it total, it is the same like OEM. And they are 2.3 mm in dia. I'm thinking now to give it a last try and change the O-rings on old ones to put them back in.
Carbs are not synched, but since the bike rode well before carb disassembly I didn't think it is necessary. Am I wrong?
YES.. re-sync the carbs... any time you touch the carbs.
A trick I was told by Randy.. for a starting point when setting your mixture screw, with filters off, (set mixture screw all way down.. lightly) reach inside thru air intake with a finger nail contacting the very tip of the needle, back off on the mixture screw until you lose contact with the needle tip. This compensates for manufacturing tolerances . I found carbs 2 and 3 where out by a half turn each, this way.
Good luck
Tony
Quote from: Antonn3 on September 08, 2015, 01:07:13 PM
YES.. re-sync the carbs... any time you touch the carbs.
A trick I was told by Randy.. for a starting point when setting your mixture screw, with filters off, (set mixture screw all way down.. lightly) reach inside thru air intake with a finger nail contacting the very tip of the needle, back off on the mixture screw until you lose contact with the needle tip. This compensates for manufacturing tolerances . I found carbs 2 and 3 where out by a half turn each, this way.
Good luck
Tony
Thanks Tony!
I did that with finger nail on the screws while the carbs were down. Mine are also different. So I'm sure now they are set the same. I'll try with synching.
Ivan
Sooo, still with the same issue. After your reply Tony I was off to synch them just to find out they are perfectly aligned. Difference at most for thickness of the needle on the gauges. I got them down again and tore them to pieces. Thoroughly cleaned, seems like air gets out everywhere it should when I blasted them. In the mean time I checked the compression in the cylinders. Almost perfectly the same in all four. Although a bit lower from the minimum value, measuring around 7 bar. But I'd say that's faulty gauge more then the engine since bike rode perfectly. got minimal compression increase when I poured some oil in a cylinder. So I ruled out engine as a cause definitely and now I'm focusing only at the carbs.
There is still the possibility that one or more is so heavily clogged that i couldn't clean it, but I doubt it. Problems started when I put new valve seats and needles in. They do look a bit different, but the hole size is correct at 2.3 mm. So I somehow doubt it's their fault, maybe the float height thingy and I will try to give it more fuel, measuring the fuel level in the bowls today since only float height measurement gave me nothing.
I'm still suspecting that striped pilot fuel jet is giving me the headache and this is where I would like to hear your experience. It's screwdriver slot is messed up, with the orifice intact and clean. Could that be the sole cause of low (and rough) idle (air/fuel mix screws are 2 turns out, floats at 21.5 mm) and stumbling on opened throttle? Diaphragms are intact. Same happens with/without the airbox. So I'm guessing if the fuel level measuring gives me nothing it could only be that pilot jet or heavy clogging that I can not fix. Thoughts anyone?
Did you manage to get anywhere with this?
I had an overflowing bowl after the bike had been stood for a good while, so decided to strip the carbs. I am no expert, but no idiot either, and I have taken days over them. I replaced the needles and seats with parts from Yambits UK, cleaned everything to the n'th degree, blew everything out with a compressor etc.
I rebuilt them, then fitted them today - It's awful.
At first it wouldn't start at all, and then, after jumping the battery (as I had flattened it) I managed to get it to run of a sorts, but it will only do so with the choke on. It fires up and revs hard to around 3500/4000 momentarily, then comes back to 2k-ish, but is hunting, spluttering etc, not idling really. If I take the choke off, it dies immediately.
I thought I had bench synch-ed OK, and thought I'll just go for it and try a vacuum synch, even with it running so bad. Problem is, there is NO suction registering on my Carbtune! Now that had stood for years too, but is mechanical, and I can raise the bars by sucking on them, so wtf have I done so wrong?
I am bamboozled.
Now I have got a second hand old tank on it, (the old one rusted through, which was the start of my woes), and whilst I had no issue with the fuel filter when it was flooding the bowl before, could this be the issue, fuel starvation? I am gonna test it off the bike tomorrow, but I'm getting fed up now.....
Any ideas as to the symptoms?
JohnnyW, what year is your FJ? How far down did you strip the carbs down? If you did not strip all the way down and use an ultra-sonic cleaner then you might need to clean them again. Sitting will cause all kinds of problems for these carb bikes. The new gas is crap!!!
Yeah, I did the full strip, the complete dismantle, carb cleaner and compressed air. I didn't use an ultrasonic, but did steep the parts for hours in the cleaner, then blew them out methodically,
I do have a few theories having gossiped with my brother tonight (a racer), so back to the drawing board tomorrow. I will report back......
It's a '93 3XW
You can't sync them when the choke is on. Air coming through the choke opening ruins the vacuum signal at the intake vacuum port.
You've got to get it to run with the choke closed to sync.
Quote from: FJ_Hooligan on October 26, 2015, 06:17:32 PM
You can't sync them when the choke is on. Air coming through the choke opening ruins the vacuum signal at the intake vacuum port.
Sorry... What?
As far as I know, the "choke" on Mikuni carbs is an enrichment circuit, plungers open into a fuel circuit and add fuel to the mixture.
Where is this openening the air would come from?
Thru the choke vents....those 4 little hoses on your carb's are vent hoses. When the choke is on, they draw in air to mix with the fuel thru the choke circuit.
This air/fuel mixture bypasses the throttle plate.
The choke circuit dumps out on the engine side of the throttle plate. The majority of the air for the choke (I refuse to type enrichener multiple times and everyone knows what I'm talking about when I say choke) passes underneath the slide diaphragm. The air Pat is referring to is a small amount of bleed air added to the fuel side of this circuit.
If you pull the diaphragm out and look at where the plunger is, you'll see that the plunger acts as a sliding throttle plate that controls the amount of air from the airbox that is allowed to mix with the air/fuel. The needle tip of the plunger is metering the amount of air/fuel allowed into the circuit. It's really like a mini carb circuit that's jetted very rich.
Anyway, if the choke is on lots of air is flowing through it and that will spoil the vacuum seen at the sync vacuum port.
Quote from: FJ_Hooligan on October 26, 2015, 06:17:32 PM
You can't sync them when the choke is on. Air coming through the choke opening ruins the vacuum signal at the intake vacuum port.
You've got to get it to run with the choke closed to sync.
Yeah, I know that. Was just a bit desperate. That explains my vacuum gauge not working correctly! Got up at 4am this morning with it all wooshing around my head, and have been in the garage ever since. Have got it all off again, and have checked my work. I cannot see any obvious mess-ups.
I do seem to be having a problem setting No2 butterfly at a 'needle's width' gap. Even with my throttle stop adjuster fully wound in, it needs to be a couple of mil more to achieve a gap that would allow a sewing needle through (as suggested by some). How much of the little holes above the butterfly would you expect to see at bench synch to be a starter for a decent idle speed? How much an initial gap? Weird how stripping it down has affected the throttle stop!?
Sometimes when they are close, but not quite, synced, it works better if you take them (all of the butterfly's) way out of sync, and bring them back in.
Nope, no joy when I re-bench synch'd it and fired it up again.
Weird thing this time is that downpipe 2 and 4 (looking from seat) got hot, but 1 and 3 didn't, so that kind of eliminates a coil problem (clutching at straws here), but I suspected my new plugs (*clutch, swipe*), so put my old ones in 1 and 3. Tried again, and this time 1 and 2 stayed cold, so didn't fire at all. Not electrical I think.
What the heck can I have done during the cleaning to f**k this up so!?
We have a great word here in Scotland to sum up my mood today after countless hours wrestling this bugger back in, airbox etc.
Scunnered I am. Scunnered.
Quote from: JohnnyW on October 27, 2015, 10:55:31 AM
Nope, no joy when I re-bench synch'd it and fired it up again.
Weird thing this time is that downpipe 2 and 4 (looking from seat) got hot, but 1 and 3 didn't, so that kind of eliminates a coil problem (clutching at straws here), but I suspected my new plugs (*clutch, swipe*), so put my old ones in 1 and 3. Tried again, and this time 1 and 2 stayed cold, so didn't fire at all. Not electrical I think.
What the heck can I have done during the cleaning to f**k this up so!?
We have a great word here in Scotland to sum up my mood today after countless hours wrestling this bugger back in, airbox etc.
Scunnered I am. Scunnered.
Hi Johnny!
I'm still nowhere with this problem. After changing the seats and needles with Keyster ones and new pilot fuel jets, thorough cleaning with carb cleaner, cooking the carbs, compressor cleaning etc., nothing. When I spray the cleaner, it comes out everywhere it should. I ruled out starvation problems by eliminating the tank when testing, giving it the fuel right into the line. New plugs just in case, but I don't think it's electrical since bike ran great before removing the carbs. Strange thing happened last time I took the carbs off and put them back on. It ran pretty good and reacted well when I opened full throttle from idle, but I needed to sync them with gauges since they were all striped down to bits. And I managed to sync them perfectly in less than 2 mins. Then it started all over again. First my idle got higher to 2.5k, I got it back down and same shit happens. It idles but when I open the throttle it sputters, chokes and usually dies. But if I manage to get it to about 2-3k RPMs, it backfires through exhaust and runs badly in general.
I'm thinking that maybe the rubbers or only O-rings between carbs and head are leaking. But I don't know how would I be able to sync them perfectly if that's the case. I also changed fuel and vacuum lines with the new ones with same inner diameter. Hoses are a bit thicker in general since the walls are thicker than the old ones. But I don't think this is an issue. I actually gave up on this and found a good mechanic. I lost a ton of nerves and it's better to give it to someone with far more experience than I have. Next I could do is to push the whole bike into the sea. :ireful:
Quote from: balky1 on October 27, 2015, 11:36:24 AM
Next I could do is to push the whole bike into the sea. :ireful:
Yep, that's how I'm feeling.
Quote from: JohnnyW on October 27, 2015, 10:55:31 AM
Weird thing this time is that downpipe 2 and 4 (looking from seat) got hot, but 1 and 3 didn't, so that kind of eliminates a coil problem (clutching at straws here), but I suspected my new plugs (*clutch, swipe*), so put my old ones in 1 and 3. Tried again, and this time 1 and 2 stayed cold, so didn't fire at all. Not electrical I think.
Johnny, if you changed the plug on #3 and now it gets hot, it sounds like you are on to something.
Just so our terminology is correct:
Sitting on the bike the #1 cylinder is on the left, #4 is on the right.
The left coil should be connected to #1 and #4 plugs, the right coil goes to #2 and 3.
So if you changed any plug, and now that cylinder is firing, you have an electrical issue.
Thanks Pat, but I'm not convinced that's the issue, as each pot was on an individual coil, and why would this suddenly fail - Coincidence? Nah, I reckon I have done something wrong.....
To back-track a little, I embarked upon this as my bike is rarely ridden, and it's a miracle it has never given me any trouble in the 22yrs I have had it, given how often it is sitting idle. My bubble burst a few weeks ago, when I got fuel pissing out of the overflow over my feet, suggesting a stuck float/needle, and no amount of banging it would coax it free. After coming home on the recovery truck, I decided to do the strip/rebuild of the carbs.
I have never had any issue with anything other than the tank rusting through, which I have replaced with an ugly but functional one for the time being. I replaced the spark plugs and changed the oil and filter whilst doing this job, but as I say, have had no running problems previously.
So, what might I have done wrong? I may have mixed up different carb parts, but I put new needles and seats in, so surely everything else is really not carb specific? I checked the float heights. I cleaned everything with carb cleaner, soaked the jets, and blew it all through with a compressor. I took my time. I followed the instructions on the sheet from Mr.Rafforth, along with a few other tutorials on the web.
Soooo,
What I am noticing now is that she fires first push, revs relatively high, then dies, and won't respond again until I have left it a while. I have an auxiliary fuel supply, gravity fed. but it does suggest that fuel 'gets through' somehow, burns off, then it doesn't get enough after that? When I could get it to kind of run previously (I have had the carbs off three time now!), it was very lumpy, and would only run on choke.
I am loathe to just take them off again, and do it all again, as it's such a wrestle to get the airbox etc back on, and mainly because I am just going over old ground. I suppose my question is what can I have done to make it so bad?
Where did you get the carb parts? Did you get the correct float needle assemblies for your fuel pump carbs? http://www.fjowners.com/index.php?topic=9836.0 (http://www.fjowners.com/index.php?topic=9836.0)
If you are sure it's not a spark problem (with a plug swap, why would #3 start working?) the only other thing I could think of is that your idle circuits are not clean.i
Quote from: JohnnyW on October 28, 2015, 10:40:09 AM
What I am noticing now is that she fires first push, revs relatively high, then dies, and won't respond again until I have left it a while. I have an auxiliary fuel supply, gravity fed. but it does suggest that fuel 'gets through' somehow, burns off, then it doesn't get enough after that? When I could get it to kind of run previously (I have had the carbs off three time now!), it was very lumpy, and would only run on choke.
Reading this part of your problem description sounds to me like the carbs are feeding too much fuel. It is really hard to diagnose this way so this my stab at it. Having to wait "won't respond again until I have left it a while" is my primary reason for thinking of flooding. The other reason is only running on choke, but that could be that the engine won't run long enough to warm up. Before this gets too frustrating you might consider sending the carbs to RPM. Everyone that has reported the bike running really well after the carbs got some RPM mojo...
FJMonkey and Pat...... I checked that I had got the correct carb set crk062, as provided by Yambits UK, covering models 1988-92, but what I haven't done is compare them to the ones I took off. My 3CV has a fuel pump, not gravity feed Pat, so I need the smaller orifice.
This would explain my issues wouldn't it, if I had the wrong size ones, but I am not sure it's likely, else everyone else who bought the kits off Yambits would be wrong. I am going to get them to check tomorrow, saving me having to strip them out again, but I reckon I may end up having to do it again anyway, and start from scratch.
Thanks for your help - It's nice to just get out of the garage and talk to people!
Quote from: JohnnyW on October 28, 2015, 01:52:12 PM
I checked that I had got the correct carb set crk062, as provided by Yambits UK, covering models 1988-92, but what I haven't done is compare them to the ones I took off. My 3CV has a fuel pump, not gravity feed Pat, so I need the smaller orifice.
That looks like the K&L kit sold here in the US. Look at the side of the brass seat and there should be the size (1.5 or 2.3) stamped into it.
Randy - RPM
Quote from: JohnnyW on October 28, 2015, 01:52:12 PM
.... My 3CV has a fuel pump, not gravity feed Pat, so I need the smaller orifice.
Yea, I saw that. that's why I went back and edited my post to you.
My mistake was that I went to the first post in this topic by a different member (balky1) and thought we were talking about his "85.
I you have the larger float needle set (gravity flow) you will be flooding your bike.
Quote from: racerrad8 on October 28, 2015, 02:58:26 PM
Quote from: JohnnyW on October 28, 2015, 01:52:12 PM
I checked that I had got the correct carb set crk062, as provided by Yambits UK, covering models 1988-92, but what I haven't done is compare them to the ones I took off. My 3CV has a fuel pump, not gravity feed Pat, so I need the smaller orifice.
That looks like the K&L kit sold here in the US. Look at the side of the brass seat and there should be the size (1.5 or 2.3) stamped into it.
Randy - RPM
Thanks guys - Yeah, I can see the size on my old seats, 1.5mm, but obviously the new ones are in the bike, and I don't want to take them out if I don't need to, i:e They are correct. I have mailed Yambits to see if they can confirm it before I strip 'em yet again. That said, if they are wrong they need to come out, and if not, I am gonna have to go back over everything again anyway, aren't I, so it looks like they'll be out again tomorrow.....?
Just to confirm you set the float level, properly and not compressing the needle spring, when you replaced the N&S.
Randy- RPM
Quote from: racerrad8 on October 28, 2015, 04:29:09 PM
Just to confirm you set the float level, properly and not compressing the needle spring, when you replaced the N&S.
Randy- RPM
Well I thought I did Randy, but that's the sort of thing I am going to double check when I get them back off again. Thanks
Quote from: JohnnyW on October 28, 2015, 04:35:36 PM
Quote from: racerrad8 on October 28, 2015, 04:29:09 PM
Just to confirm you set the float level, properly and not compressing the needle spring, when you replaced the N&S.
Randy- RPM
Well I thought I did Randy, but that's the sort of thing I am going to double check when I get them back off again. Thanks
Having the UNI pods makes the carb removal much less of a :ireful: task
Having the UNI pods makes the carb removal much less of a :ireful: task
[/quote]
I thought I might, but having read another FJ site, this chap felt the lack of support from the air box meant the carbs vibrated more, could lead to the manifolds splitting, and also you need to rig up a crankcase breather filter too, and that gets very oily. Thoughts? Experience? I am all for improvement, but I don't want to create myself some more problems.
I have unipods on my FJ. As short and stiff as the rubber manifolds are I don't forsee any problems with them supporting the carbs. In the old days before air boxes, manifolds supported the carb and an air cleaner as with singles and twins. If your manifolds are cracking it is time to replace them. Heat and old age make them brittle. They are rubber to reduce the heat and vibration from the cylinders to the carbs. Dave
Quote from: JohnnyW on October 29, 2015, 03:13:14 AM
rig up a crankcase breather filter too, and that gets very oily.
The breather is quite easy. A hose just long enough to put the breather filter in between and just under the two pods. When the engine is running the oily air is in the air flow and sucked back in, much like the air box connection. When I get a chance I will pull the seat and take a photo, and see how oily it is under there.
Crank Case Breather (http://www.rpmracingca.com/proddetail.asp?prod=Engine%3ABreatherFilter&cat=39)
(http://www.rpmracingca.com/prodimages/large/Engine%20BreatherFilter-1.jpg)
Quote from: JohnnyW on October 29, 2015, 03:13:14 AM
I thought I might, but having read another FJ site, this chap felt the lack of support from the air box meant the carbs vibrated more, could lead to the manifolds splitting, and also you need to rig up a crankcase breather filter too, and that gets very oily. Thoughts? Experience? I am all for improvement, but I don't want to create myself some more problems.
Quote
I sell a more than five hundred RPM Dual Pod Foam Air Filter (http://rpmracingca.com/proddetail.asp?prod=Carb%3ARPMPod) a year and I have never heard from a single customer of any intake cracking or breaking problem.
I also sell a ton of these, which work perfectly on the breather hose; RPM Breather Filter (http://rpmracingca.com/proddetail.asp?prod=Engine%3ABreatherFilter)
Also, every Legend car running in the world today and over the last 22 years has never has an airbox to "support the carbs".
Finally in closing, the airbox offers minimal "support" to the carbs as the boots between the carbs & the air box are very thin and are a means of absorbing the movement/flex between the engine and the sub-frame for which the air box is rigid mounted.
Randy - RPM
Quote from: JohnnyW on October 28, 2015, 10:40:09 AM
So, what might I have done wrong? I may have mixed up different carb parts, but I put new needles and seats in, so surely everything else is really not carb specific? I checked the float heights. I cleaned everything with carb cleaner, soaked the jets, and blew it all through with a compressor. I took my time. I followed the instructions on the sheet from Mr.Rafforth, along with a few other tutorials on the web.
What I am noticing now is that she fires first push, revs relatively high, then dies, and won't respond again until I have left it a while. I have an auxiliary fuel supply, gravity fed. but it does suggest that fuel 'gets through' somehow, burns off, then it doesn't get enough after that? When I could get it to kind of run previously (I have had the carbs off three time now!), it was very lumpy, and would only run on choke.
I am loathe to just take them off again, and do it all again, as it's such a wrestle to get the airbox etc back on, and mainly because I am just going over old ground. I suppose my question is what can I have done to make it so bad?
So, an update -
I have completely stripped them down again, twice, and in fact the float bowls three times
I have checked the new valve seats, they are 1.5mm as per a fuel pump model
I have checked, double checked and bloody triple checked the float heights - 22.4mm give or take 0.5mm
I have checked the floats aren't cracked
I have cleaned with carb cleaner, blown and dried every orifice I could with compressed air, ditto the jets
I have checked my new plugs are firing
I have cleaned and re-oiled my K&N standard replacement filter
I have checked both the airbox and inlet manifolds for leaks, at least visually, and can see none - The rubbers seem pliable and in good condition
The only progress I have made is that it runs for longer, but still requires the choke. As I let the choke in, it now revs spontaneaulsy to 4-5k before faltering, dropping back to say 1500 on choke slightly open, but kind of hunting/lumpy really. It will not really run without some choke.
I did think me being more careful with the float heights seemed to have helped a wee bit, but only thus far.
When I bench synched it, the butterflies were only a mil or so open
So I have checked the float heights, and have blown out the pilot/idle circuits. I have fuel, I have a spark.
What can I have done that is causing this?
The bike was running perfectly fine until the over-flowing carb led me to this strip down.....I just cannot see what I can have done, undone, re-done again?
I don't have the option of Randy at RPM, living in Scotland, (let alone the cost).
I am really fed up, and have spent over a man-week working on this. I am at a loss.
Quote from: balky1 on October 27, 2015, 11:36:24 AM
I actually gave up on this and found a good mechanic. I lost a ton of nerves and it's better to give it to someone with far more experience than I have.
So did you let someone have a look at it Balky1? I am starting to think I will need to, but I wonder what thy're going to do differently?
Quote from: FJmonkey on October 28, 2015, 07:55:02 PM
Having the UNI pods makes the carb removal much less of a :ireful: task
:rofl2: Which it really isn't... I like the airbox. Mainly because I don't have to spend the money on jets and new filters. :smile:
Quote from: JohnnyW on November 03, 2015, 02:18:17 PM
So I have checked the float heights, and have blown out the pilot/idle circuits. I have fuel, I have a spark.
When you measure float heights, are you measuring both sides of a float? If they are not even, you are going to have a ton of grief, as the actual level won't be what you think. I accidentally bent mine and found this out the hard way.
Yep, measured both sides. Three were fine, but there was a small difference in one of the carbs, but I didn't want to bend it for fear of breaking it. One side was maybe 1mm higher than the other, but I set it at mid-way between the two, my reasoning being that the tolerance would cope with that. In hindsight, it may lead to a skewed lifting of the tang, but would that cause such an issue that I am having?
You measure the float correctly http://www.fjowners.com/index.php?topic=9560.0 (http://www.fjowners.com/index.php?topic=9560.0)
I just want to make sure you are measuring the floats level properly. If they are twisted, like you mentioned then you should straighten it out by gently twisting it back to flat and then setting the float level.
Here is some photos I have taken from my GYSM I posted many moons ago but I can't find them right now.
(http://i1215.photobucket.com/albums/cc517/racerrad8/FloatAdjust012.jpg~original) (http://s1215.photobucket.com/user/racerrad8/media/FloatAdjust012.jpg.html)
(http://i1215.photobucket.com/albums/cc517/racerrad8/FloatAdjust011.jpg~original) (http://s1215.photobucket.com/user/racerrad8/media/FloatAdjust011.jpg.html)
(http://i1215.photobucket.com/albums/cc517/racerrad8/FloatAdjust010.jpg~original) (http://s1215.photobucket.com/user/racerrad8/media/FloatAdjust010.jpg.html)
(http://i1215.photobucket.com/albums/cc517/racerrad8/FloatAdjust009.jpg~original) (http://s1215.photobucket.com/user/racerrad8/media/FloatAdjust009.jpg.html)
(http://i1215.photobucket.com/albums/cc517/racerrad8/FloatAdjust013.jpg~original) (http://s1215.photobucket.com/user/racerrad8/media/FloatAdjust013.jpg.html)
It might be worth check to see where you float level is externally to see if it is running out of fuel.
(http://i1215.photobucket.com/albums/cc517/racerrad8/FloatAdjust008.jpg~original) (http://s1215.photobucket.com/user/racerrad8/media/FloatAdjust008.jpg.html)
(http://i1215.photobucket.com/albums/cc517/racerrad8/FloatAdjust007.jpg~original) (http://s1215.photobucket.com/user/racerrad8/media/FloatAdjust007.jpg.html)
(http://i1215.photobucket.com/albums/cc517/racerrad8/FloatAdjust006.jpg~original) (http://s1215.photobucket.com/user/racerrad8/media/FloatAdjust006.jpg.html)
Now, I have to ask...You have completely disassembled the carbs; every jet, pilot screw, emulsion tube and everything else have been removed from the carb body with the exception of the throttle plate & shafts?
You have the new o-ring on the pilot mixture screw?
What are the mixture screws set to?
What jets are in the carbs now; Main, pilot & air bleed?
Just looking for an answer to your issue and that information will be the first stop.
Randy - RPM
EDIT: I see copper beat me to the float measuring part
Make sure you measure from the correct spot on the float.....the upper curved surface. See post #4: http://www.fjowners.com/index.php?topic=9560.0 (http://www.fjowners.com/index.php?topic=9560.0)
Quote from: racerrad8 on November 03, 2015, 04:06:56 PM
I just want to make sure you are measuring the floats level properly. If they are twisted, like you mentioned then you should straighten it out by gently twisting it back to flat and then setting the float level.
I realise I should have tried to have done that with the one slightly-off one now. I am pretty sure I did everything else as per your and various other tutorials
Now, I have to ask...You have completely disassembled the carbs; every jet, pilot screw, emulsion tube and everything else have been removed from the carb body with the exception of the throttle plate & shafts?
That's correct
You have the new o-ring on the pilot mixture screw?
Yes, except I have now taken them out and put them back twice more
What are the mixture screws set to?
3 turns
What jets are in the carbs now; Main, pilot & air bleed?
Whatever was standard FJ1200 3XW, I have had the bike since new. 110 main I know, not sure with the others
Just looking for an answer to your issue and that information will be the first stop.
Sure, I really appreciate the assistance
Randy - RPM
EDIT: I see copper beat me to the float measuring part
G'day,
I read over the various posts and all the problems you are having. I have an '85 FJ1100 with high mileage. I did notice with mine that I had alot of trouble early on with idling etc. I bought some nice cond. choke plungers and replaced my old ones. Doing this improved the idle no end.
My old choke plunger's rubber grommets had hardened oval, and when I reassembled the carbs after numerous attempts to clean them properly, I had placed the choke plungers back in differently, causing air leaks into the circuit. thats when i bought better condition ones and it solved my problem.
A good way to see if you have a similar problem is look at the plungers when you disengage the choke at the handlebar, if they stick out or do not seat properly, that may be causing your odd running.
Also, RPM sell a replacement:
https://www.rpmracingca.com/proddetail.asp?prod=ChokePlunger (https://www.rpmracingca.com/proddetail.asp?prod=ChokePlunger)
Also, fuel hose routing, mine was a bastard to get right! I created easier pipe routing for my FJ.
(http://fjowners.com/gallery/2/1121_08_07_11_5_24_22.jpeg)
(http://fjowners.com/gallery/2/1121_08_07_11_5_25_08.jpeg)
Good tip on the carb plungers :good:
Looking at the pictures of your fuel line routing, it appears that the right side branch line has a slight pinch where it joins carbs #3/4.
If you make those branch lines longer they will have less of a bend to them, resisting a pinch when the lines heat up. Then you could run the single fuel line (to the petcock) under the 2 branch lines like the oem route.
Worth a try on the plungers. The collars didn't seem overly perished, but I am desperate now.......will let you know how I get on!
G'day,
Yeah, after I took the pics I remember having to buy more pipe for a better fit. The main reason I did it that way was to get more lift when removing the tank, it worked well with the pipe over the junction and not under.
JohnnyW: The rubber collars may not seem perished, but if they are rock hard, the brass plungers may have worn oval, using your finger slowely rotate and push in and out to find where the most resistance is, if any.
Also, on my bike the choke actuation rod that runs down the length of the carby bodies had worn into the carb body aluminium, making it difficult to actually use the choke. maybe not a prob with yours, but a prick to fix.
Good luck, Gareth
Quote from: JohnnyW on October 29, 2015, 03:13:14 AM
Having the UNI pods makes the carb removal much less of a :ireful: task
I thought I might, but having read another FJ site, this chap felt the lack of support from the air box meant the carbs vibrated more, could lead to the manifolds splitting, and also you need to rig up a crankcase breather filter too, and that gets very oily. Thoughts? Experience? I am all for improvement, but I don't want to create myself some more problems.
On allusions :i_am_so_happy:
My web is done for the use AND abuse of the FJs. I know personally 5 owners that go regularly on closed race tracks aboard their FJs, and in Mainland Spain still you can travel all day long between 160-200 km/h without too hassle in secondary roads (named "General roads" here).
By other side, in Spain the level of familiar incomes are not like on the US, Australia or UK. So it means that only a minority of us are owners of multiple motorbikes, and the typical FJ owner uses his only bike for everything: from daily workhorse to play races on weekends with more modern machinery, and in any kind of weather, from very hot in summer to snow in winter
For that kind of abuse I cant recommend individual filters. Test on yourself: without the air box support you can move the carbs up & down simply by hand. Imagine the forces with riding hard!
And with the airbox manifolds greased with red rubber grease the time to get out the carbs is near exactly the same that with individual filters
And like reliability is a must, I cant recommend to suppress the secondary oil circuit that go to the head (pic taken from Yamaha workshop manual)
(http://i1133.photobucket.com/albums/m589/fj1200alf/Oilcircuit.jpg) (http://s1133.photobucket.com/user/fj1200alf/media/Oilcircuit.jpg.html)
In my favour, Practical Sportsbikes mag recommend like a general rule in 70-90 bikes fitting OE airbox if you want everything going sweet
Cheers Alf. I had already been on your site, and had the same thoughts myself anyway, hence my comments above.
As I live in Scotland, and the weather is awful right now, the poor beast is sat in my garage looking very sorry for itself, awaiting me to get the energy to start to tackle it again.
I am still at the 'what the hell have I done wrong' stage, as I have checked, double checked, stripped and rebuilt countless times now, but still have the same problem.
Quote from: JohnnyW on November 03, 2015, 02:23:29 PM
Quote from: balky1 on October 27, 2015, 11:36:24 AM
I actually gave up on this and found a good mechanic. I lost a ton of nerves and it's better to give it to someone with far more experience than I have.
So did you let someone have a look at it Balky1? I am starting to think I will need to, but I wonder what thy're going to do differently?
Hi JohnnyW!
Yes, I drove my bock to a repair shop, hopefully they can find out what happened. Sorry for a late reply, for some reason I wasn't informed by e-mail about new posts in this topic.
Best of luck!
Ivan
Johny
You have checked every possible issue regarding to carbs, I see. So I think its time to look to other places. You say you have spark and your coils are perfect and the connection between wires and spark plug caps are fine. I supposse the fuel petcock is working properly and that you have tried to sync the carbs when refitted
Well, I am going to speak with another 2 competent mechanics (FJ owners both) and I hope to have any suggestion
Thanks Alf.
The issue is that the bike was working fine before I had the sticky float/fuel overflow. That prompted the strip/new gaskets/new needles & seats/clean. Only then, when I put the carbs back on has the high revving/rough running happened. I have done the usual checks on the coils/plugs/HT leads, but really had no reason to suspect them anyway.
I suppose the symptoms suggest the inlet manifold is leaking, but they all look sound to me, no cracks obvious.
Stupid question: after reassembly the carbs on the bike, have you sync them?
I have bench-synched them, yes, using a sewing needle as the guide on the butterflies, but cannot vacuum synch them as it won't run on idle without the choke, and therefore there is no vacuum.
The only questions that are stupid Alf, are the ones we don't ask ;)
I asked it because after much discussions my friends and me think that your problem is simpley due to incorrect sync. My friend Mingo and myself, both have had this problem years ago, Mingo in his bike and myself in another 86 1TX.
In my case, only after a lot of tries and screwing the idle to 3.000 rpm. I could have the bike running enough time to start to sync the bike. When stabilized, it was then a doddle to finish the correct sync procedure and having the bike running without problems
Dont rely on the stactic idle measure. You need a vacuum
After re-reading the posts, and imagining the enormous frustration at not being able to think of what was done wrong, try from the start again, but keep it really simple. I have messed up quite a few attempts to get a bike running properly, only to discover I installed something incorrectly.
Here is a sampling of some easy mistakes to make: (some I have done)
-installed diaphragms reversed -doing this really messes up things
installing something upside down -it happens...
not taking care when putting stuff back together, and bending something -this is a real bastard!
crimping choke or accelerator cable -this does interesting stuff
blocked hoses -blow up 'em, should be clear.
electrical -did you bump wiring, dislodge something, wiring to the coils? very important...
coil leads -check the resistance, a bad lead will wreck things for tuning.
in other words, try to re-check on how you assembled the carbs, it is hopefully something really simple. I always dis-assemble carbs one by one, that way I have a good reference if I am unsure of something. Maybe bench synch with a bigger object, a drill bit for instance.
Anyway, just some thoughts, good luck
Gareth
Hello there.
I had exactly the same symptoms after leaving my FJ11 for 9 months, in the corner on it's own.
Terrible.
Carb cleaner. Two cans. Fuel additive (Wurth) two cans. Eventually I took the advice of a Brit FJ bloke and took the carbs off. It's horrible, I know...the daft airbox etc. But I took my time and the carbs came off. I cleaned all I could see on the outside.
Then I unscrewed the float bowl screws and the top screws. All slow and careful.
Diaphragms looked OK ( but who am I?). Then I got to the emulsion tubes. 4 of them.
Two were full of crap. One contained an insect. I am amazed that the bike ran. I have the pictures.
I left the emulsion tubes in carb cleaner (after removing the fly) and made sure they were completely clean....all the little holes. I even used a Jewellers loupe to see if they were clean.
Carefully reversed the dismantling and slowly put them back together.
Remember I only cleaned the emulsion tubes.
She started and runs as well as she did before. That's good enough for me. And now I ride her every day, to buy er...milk, beer, cigs, pizzas or wine.
Best wishes
Tony
The other option I would try, if you haven't already done this, is to put the original needles and seats back in and try it.
I have heard some iffy stories about keyster stuff and Yambits supplied parts. Nothing to lose.
Aye, not a daft idea.
I am scunnered* with it at the moment, and just keep squeezing by it in the garage, all forlorn. It is going to have to wait until we get the odd day of blue skies and my thoughts turn to the road, rather than wind, rain, ice and snow which is the Scottish situation right now.
I will not be beaten, though I am 2-1 down in extra time right now...... ;)
* Scots for absolutely pissed off!
Haha!
My bike is finally returning from the shop. There was a problem with the rubbers that hold the carbs and with carb tunning and my lack of experience.
But, another problem! I never had it before! Guy says he can't open the fuel cap! One of the pinions works fine, but the other one won't loosen up! Any ideas?
Ivan