Hi all. Had several cracks at putting this up it keeps becoming a novel so :-) going for the shortest version.
86FJ ex US. Cuzzie (retired bike shop owner//mechanic) had her for 10 years. No major issues. Serviced properly etc...was his pride and joy now mine almost 18 months.
Running issues started about a year ago with the occasional miss at speed. .... then came intermittent loss of power, to the point where I even got passed by a Harley.Long story short, now goes extremely well or 10-15mins...then doesnt. Any request for power (even just a little bit to get over 30mph) is met with stutter and missing, and a hill will result result in death under power almost as if 2 cylinders cut out.....pull in clutch and rev....back to 4.....let' out clutch....dies.. that results in over heating on one and the start to loose clutch (since adjusted clutch) Have done carbs (cleaned checked ... then a reconditioned bank. Plugs, caps, coils, tested and swapped, swapped primary coil ..tested outputs, ( all within spec).
New TDI don't start from cold then but didn't change result after 15 mins.
Initially rode for 30+ ks with Fuel cap open...no difference....
Have access to testing gear from cuzzies time as a mechanic...so it's not guess work. Stumped.
Have you got a vacuum controlled petcock ?
George
Quote from: movenon on January 11, 2014, 02:44:20 PM
Have you got a vacuum controlled petcock ?
George
If his 86' is still stock then yes he has one. And that means he needs to perform the "Suck Test", follow the link.
http://www.fjowners.com/index.php?topic=10019.msg96039#msg96039 (http://www.fjowners.com/index.php?topic=10019.msg96039#msg96039)
Yes he does.
It sure sounds fuel related. The 3 most common issues on gravity flow FJ's (84-87) are
1) improper fuel line routing: as the single line leaves the petcock, this line should run *under* the 2 branch lines which feed the carbs. This is critical. If the fuel line incorrectly runs over the 2 branch lines, when the fuel line warms up and gets soft, the fuel line will pinch, impeding fuel to the carbs.
2) the petcock opens and closes based on a vacuum signal off your #1 cylinder intake manifold. Double check the condition of your vacuum line. Make sure the connections at both ends (petcock and intake manifold) are snug.
3) the petcock diaphragm not holding a vacuum thus causing a interruption of fuel flow. Do the suck test.
Connect a piece of tubing (hopefully clean) to the vacuum port on your petcock. Now lightly suck, you should hear your petcock click open, you should not be able to draw air thru the tubing...if so your diaphragm leaks...also while you suck, block the open end of the tubing with your tongue, you should be able to hold a vacuum in the line, if not your diaphragm leaks.
The solution is a new petcock from RPM.
2 options on a new petcock :
a) a new expensive 86/87 petcock that has the electric reserve or
b) a less expensive 84/85 petcock that has no goofy reserve switch but does have a 'prime' setting which will get you home in the event that, if in the future, the vacuum function stops working.
We have yet to find a suitable rebuild kit for our petcocks. Our only option has been to buy a new oem.
Hope this helps. Pat
Hi Pat ....and thank you. Sadly have tried the suck test.. also replaced the vac line to #-1 just in case.
Cuzzie had replaced the petcock.. has a 1100 petcock with prime. Have tried with both options. And with tank cap open. :dash1:-
Due to the length of the saga and the number of timess I have related the issues I feel like everyboldy has heard the tale of woe....sorry omitted a few such details. The replacement carb bank has required adjustment to fuel Line as there is only one entry point in the centre of the bank. Cuzz has assured me. There was sufficient gas getting to bowl. Metered testing and balancing did tend to confirm that. .....equally everything tends to point back to that area.
Have also enclosed line in "non crush" at critical points to try to alleviate that or kinking as an issue. We have been concentrating on electrical then fuel.....back to electrical....back to fuel.....
Quote from: movenon on January 11, 2014, 02:44:20 PM
Have you got a vacuum controlled petcock ?
George
Hi George. Yes. But it does have prime....:-)
So, just to confirm...
The bike has the missing problem when it is operated with the petcock in the "prime" position as well?
Randy - RPM
It could still be fuel line routing/pinched issue.
Ooooh, this is a good mystery....
Brian, when the bike studders and misses....are the plugs wet or dry?
If dry, then it's fuel...if wet, then it's spark...
Occasional miss followed by a more constant miss could be electrical....if your coils are ok, how about the voltage to the coils? Check the point to point ohm resistance? Have you cleaned and sanded all your electrical connections? Why not try the coil relay mod, it can't hurt.
How about the coil signal from the ignition pickup? Good ohm readings on the signal wires?
Quote from: FJmonkey on January 11, 2014, 05:39:50 PM
It could still be fuel line routing/pinched issue.
If he has the center feed fuel pump carbs (no branch lines) I don't see how the fuel line could pinch.
Based on my experience, I do know that on the fuel pump models (89-94) when the pump fails you can bypass the pump (in a pinch) and run the bike on gravity flow to get you home...but when the tank empties down to below 1/2 full and the head pressure drops on the fuel line, the bike can start running poorly....
Does the center feed carbs contribute to this condition? Could be...
Come to think about it....I'm not sure the fuel pump carbs (center feed, small float seats) and be run reliably with a gravity flow system.
You beat to the 88-93 1.2 Needle and seat fitment Pat :good2:
I don't understand what is being said here. "New TDI don't start from cold then but didn't change result after 15 mins." ?
Does it start every time now ?
George
Quote from: Pat Conlon on January 11, 2014, 06:01:10 PM
If he has the center feed fuel pump carbs (no branch lines) I don't see how the fuel line could pinch.
Based on my experience, I do know that on the fuel pump models (89-94) when the pump fails you can bypass the pump (in a pinch) and run the bike on gravity flow to get you home...but when the tank empties down to below 1/2 full and the head pressure drops on the fuel line, the bike can start running poorly....
Does the center feed carbs contribute to this condition? Could be...
Come to think about it....I'm not sure the fuel pump carbs (center feed, small float seats) and be run reliably with a gravity flow system.
I missed that he changed over to center feed like the FP carbs. So he now has one 6MM hose vs. two 10MM hoses, I don't see how that could be a problem. :sarcastic: If he did not keep the larger needle seats then there is one more restriction that Pat suggested.
Quote from: racerrad8 on January 11, 2014, 05:30:25 PM
So, just to confirm...
The bike has the missing problem when it is operated with the petcock in the "prime" position as well?
Randy - RPM
Hi Randy. Yes. goes fine for the first 10mins either way....... on vac setting or prime....outcome is still the same around the same set test course. Up till 10 mins (15 mins max) will rock up to. 80 mph no issues Then starts playinng up/ when asked to do a hill or accelerate above 35mph.... once that happens the missing and farting is continuous and will eventually die as she feels likes she seems to drop cylinders.
Quote from: movenon on January 11, 2014, 06:06:31 PM
You beat to the 88-93 1.2 Needle and seat fitment Pat :good2:
I don't understand what is being said here. "New TDI don't start from cold then but didn't change result after 15 mins." ?
Does it start every time now ?
George
Yes starts every time with old unit....
The new TDI is a kiwi made replacement that has an electronic advance. It will start the bike if it is warm but not from cold. I had both tdi temp on bike.... the vacuum sys (original) starts her first time and fires up immediately from cold with choke. When warm I switched over to the new electronic version to see if the original was at fault causing the missing when warm.. they both performed the same...... didn't matter what one was used.....10 mins sad face.
Quote from: Pat Conlon on January 11, 2014, 05:45:49 PM
Ooooh, this is a good mystery....
Brian, when the bike studders and misses....are the plugs wet or dry?
If dry, then it's fuel...if wet, then it's spark...
Occasional miss followed by a more constant miss could be electrical....if your coils are ok, how about the voltage to the coils? Check the point to point ohm resistance? Have you cleaned and sanded all your electrical connections? Why not try the coil relay mod, it can't hurt.
How about the coil signal from the ignition pickup? Good ohm readings on the signal wires?
Quote from: racerrad8 on January 11, 2014, 05:30:25 PM
So, just to confirm...
The bike has the missing problem when it is operated with the petcock in the "prime" position as well?
Randy - RPM
Yes Randy....either vacuum or prime...same result
Quote from: Pat Conlon on January 11, 2014, 05:45:49 PM
Ooooh, this is a good mystery....
Brian, when the bike studders and misses....are the plugs wet or dry?
The plugs have fouled and was told that suggested flooding.....that goes directly against the heating up by leaning out..... on #1doesnt it?
If dry, then it's fuel...if wet, then it's spark...
Occasional miss followed by a more constant miss could be electrical....if your coils are ok, how about the voltage to the coils? Check the point to point ohm resistance? Have you cleaned and sanded all your electrical connections? Why not try the coil relay mod, it can't hurt.
How about the coil signal from the ignition pickup? Good ohm readings on the signal wires?
Would she run so well if that were a problem ....Like Isaid the first 10 mins are excellent
What is the coil mod?
CUZ has tested all resistances and connections and we have swapped around mixed and matched coils and primary pickups.. all readings are where they should be... the only faulty one was a plug cap, so changed and re tested all 4. All good.
Quote from: FJmonkey on January 11, 2014, 06:16:38 PM
Quote from: Pat Conlon on January 11, 2014, 06:01:10 PM
If he has the center feed fuel pump carbs (no branch lines) I don't see how the fuel line could pinch.
Based on my experience, I do know that on the fuel pump models (89-94) when the pump fails you can bypass the pump (in a pinch) and run the bike on gravity flow to get you home...but when the tank empties down to below 1/2 full and the head pressure drops on the fuel line, the bike can start running poorly....
Does the center feed carbs contribute to this condition? Could be...
Come to think about it....I'm not sure the fuel pump carbs (center feed, small float seats) and be run reliably with a gravity flow system.
I missed that he changed over to center feed like the FP carbs. So he now has one 6MM hose vs. two 10MM hoses, I don't see how that could be a problem. :sarcastic: If he did not keep the larger needle seats then there is one more restriction that Pat suggested.
Sorry for not replying straight away still fighting the keyboard on this bloody tablet.....
Funny you should say that..... asked the same question myself.....I wondered if I needed to put a pump on her.....or revert back to the other routing system and alter the supply system....or somehow feed direct to each carb
We are keeping in mind that it was doing this prior to the carbs being changed......
As I understand it the carb body was used to house all the good bits from my carbs as the new body allows for full adjustment
Lets recap:
1. Problem existed before carb change to center feed configuration.
2. Problem is not related to petcock vacuum control as it occurs in PRI position.
3. Fuel line routing not as critical due to center feed mod.
4. The electronics seem to have been checked and rechecked.
5. Tried the fill cap open, no changes.
6. 10 to 15 running minutes till the problem occurs.
Seems like the question of plugs wet or dry still needs to be answered. Fuel or elictrickery is still not determined.
Quote from: FJmonkey on January 11, 2014, 09:36:30 PM
Lets recap:
1. Problem existed before carb change to center feed configuration.
2. Problem is not related to petcock vacuum control as it occurs in PRI position.
3. Fuel line routing not as critical due to center feed mod.
4. The electronics seem to have been checked and rechecked.
5. Tried the fill cap open, no changes.
6. 10 to 15 running minutes till the problem occurs.
Seems like the question of plugs wet or dry still needs to be answered. Fuel or elictrickery is still not determined.
Have you taken a plug reading after it starts to run poorly? You mentioned something about heat in your first post. Possable air leak between the manifold and engine head. O rings there might be leaking air or cracked manifold. Some starting fluid might help diagnose that.
Probably would not hurt to take a look at the ignition pick up and pick up plate and make sure it's tight. I have never heard of one failing or being loose but its an easy check and anything is possable. Also the connectors.
Keep kicking the can.... :good2: Have faith, in the end it will probably be something real simple.....
George
Will head in that direction.....o rings.....plug wet dry etc. Back after that....
cheers
Just a quick thought, I cannot remember if I read this online or from a friend, but it may be worth considering an electrical fault that worsens as it warms up. For some reason I remember being told that if a casing is cracked, for instance an altenator casing, as it warms a gap will open causing a gap in adjustment, when it cools the gap closes and the bike runs fine. So I guess look for electrics that are secured to a casing that can heat up.
There are a couple of areas that may be affected by expansion when they warm up, maybe altenator bushes.
Perhaps grab a multi-tester, and monitor the charging rate to the battery as the bike warms up, if it fluctuates too much, it may be the cause.
Just a thought, might be worth looking at.
Cheers, Gareth
Quote from: NZ FJ Rider on January 11, 2014, 11:37:30 PM
Will head in that direction.....o rings.....plug wet dry etc. Back after that....
cheers
I just read this post for the first time. I had a problem with the manifold o rings that only showed up after it was good and warm. And I had done the starting fluid test, and even sprayed waters on the manifolds. No change either way. Checked every thing a hundred times. Luckily Randy in all his wisdom had included the manifold o rings in carb kits. So I went ahead and replaced them as a last resort... fixed it (symptoms not the same but it only showed up after it was warm and repeated tests didn't show a leak)
OK , maybe the thread is dead, but I do not see that the poor running issue was ever resolved. Here's my 2 cents worth.
The symptoms described sound very much like those I've heard/seen on more than a half dozen (8 or 10 even) bikes in the 10 years my shop was open. Locating the problem the first 2 or 3 times was really tough as the symptom would not display until the bike was 20 k out on the road. What it came down to was intermittent bad connection between
the connector terminals and the circuit board of the ignition control module. Yes the board is potted but this does not prevent a cold joint. This can be proven two ways. #1 With the module in sittu use a heat gun to warm the box up, hot to the touch, #2 With the module in hand ,still connected (engine running, both tests)module in one hand,plug in the other apply some torque to the plug. Don't pull, but bend/twist the plug. If the problem is there' two cylinders will drop out as one channel of the module quits. You will look like a fucking hero. A talented electronics guy can fix this for a fraction of the price of a new module.
Well Hi guys. Its coming up for 3 seasons of rides missed, so its been a long time since I looked in ...but the saga continues.
Lost a lot of enthusiasm after trying all your (and other) suggestions, and variations of those suggestions, and exhausting all the knowledge and hands on assistance available to me...and still being no further ahead.
Gotta get her going this season. The temptation to go with the advice given (admittedly cant be good advice from a harley rider and a duc rider can it?...) to get on one of my diggers and dig a big hole....... hmmmm
They say they don't know anyone else with that sort of patience.....
There.... thank you...... feel better already.... will call back soon
Regards
Brian
NZ FJ Rider (well.... owner)