Runnipng Rough

[NZ FJ Rider]

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.

[NZ FJ Rider]

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.  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

[FJmonkey]

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.

[movenon]

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.... Have faith, in the end it will probably be something real simple.....
George

[NZ FJ Rider]

Will head in that direction.....o rings.....plug wet dry etc. Back after that....
cheers

[mr blackstock]

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

[giantkiller]

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)

[Earl Svorks]

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.

[NZ FJ Rider]

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)