Newly resurrected engine running, but just barely...questions for experts.

[ziggy682]

So, I just recently revived this 83 Vision, that hasn't run in probably 5 years.  I rebuilt the carbs, bebuilt the petcock and fuel pump, used por-15 on the fuel tank, replaced the battery, changed the plugs, cleaned the starter and contacts, changed all the fluids, and cleaned up 5 years worth of dirt, leaves, and oil.  So, the other day, I finally started it up for the first time, and it actually ran, just not very well.  Basically idle is really rough, and the bike has no power at all.  I took it for a couple of test drives up and down the road a few times, trying to figure out what was going on.  Several times, it would be running very rough and sluggish, and then, all of a sudden, it would just start running like a champ and have tons of power.  The power kept coming on, and going off completely randomly.  It seems to be just running on one cylinder most of the time, and then it will just randomly run on both cylinders.

With the bike running, I can pull the front plug wire and it won't really affect how the bike is running.  When I pull the rear plug wire, it instantly dies.  This led me to believe that the front cylinder just wasn't getting any spark, but here's where it gets weird.  If I pull that plug, or hook another plug up to that wire, it is getting a nice spark.  I can put a screw in the plug wire, and it will arc almost 1/2 an inch with a nice spark.  Also, if I just leave the front cylinder plugged in, and unplug the rear cylinder, the bike will start up and run on only the front cylinder, so I know it is getting fuel and spark up there.  If the bike is already running, and I unplug the front cylinder, it doesn't affect it, but I can still start the bike with just the front cylinder plugged in.  I know this sounds a bit confusing, but it's a bit hard to explain.

I thought maybe, the stator is a bit weak, and voltage is just too low to provide spark to both cylinders at the same time.  The bike is only putting out about 12.75 volts running, so I know the stator is weak.  So, I hooked up the batter charger to it, and started it up.  Running like this, it was putting out about 13.4 volts, but the higher voltage from the battery charger didn't make a difference.

Anyway, I'm looking for some ideas from experienced Vision owners.  I think the problem is electrical, and it might just be a combination of several poor connections.  I will most likely try to clean all the electrical connections on the bike and see if that helps.  By the way, are there any grounds on the chasis of the bike, or does everything just ground back into the battery?  I know that poor grounds could cause something like this to happen.

Oh, one other symptom is that the tach is not working at all.  All the lights, and everything else in the instrument cluster appear to work, but not the tach.  I've read that the tach runs off the rear cylinder coil, so that is strange, because that's the cylinder that seems to run all the time.

Any ideas/comments would be greatly appreciated.

Mike

[h2olawyer]

Welcome, Ziggy!

The main electrical ground is under the coil mounted to the left side of the frame.  You may have some corrosion there.  You appear to be getting good spark & the voltage is low but enough to let the TCI do it's stuff.  Go through & clean every electrical connection you can find.  Between that & the ground, you may get the stator voltage up to 14+ volts like it should be.

The tach malfunction could be anywhere in the tach circuit from the TCI to the coil to the tach itself.  Not a real common problem, but it has been talked about here before.

The carbs are often a real problem to get clean enough.  I've never worked on 83 carbs so I'll leave any possible problems to Lucky & others with experience in them.  Could be adjustments & synch.  Your YICS may be leaking as well.

You're obviously headed down the right direction since you've got it running.  That's a great start.  Getting it running at peak efficiency & power takes time but is well worth the effort.

H₂O

[kwells]

I would still question the carbs...were they dipped and cleaned maticulously?  they are very picky...if you have spark I would turn to fuel

[vavision]

I don't know too much about 83 carbs, but cleaning the 82 are like keeping a girlfriend happy. Takes alot of meticulous work initially and then you damn better keep it up the maintenance or things will go right back to worse.

[Extent]

If it was only putting out 12.75 volts while running you've defenatly got an electrical problem and probably a failed stator.  Run through the Electrex troublefinding chart, that'll help you figure out for sure if it's a grounding problem or not.

The bike should run fine even just off the battery though (been there, done that, all the way till the headlights dimmed and bike shut off)  Could something be wrong with your front sparkplug?  Maybe it got fouled up or the gap was messed up, when only the front is hooked up it's got enough juice to jump the gap but when both are plugged in it cuts out.  Just guessing, and that dosen't explain your tach problems.

[ziggy682]

Thanks for all the suggestions so fat.

When I rebuilt the carbs, I was very meticulous.  I literally pulled every single thing apart, cleaned it all by hand, and then dipped all the parts for about 48 hours, before reassembling everything with new gaskets, jets, etc.  I'm sure the carbs need some adjustment, but I'm pretty sure everything is pretty clean inside.

When the bike acts up, it's like someone flipped a switch.  It either runs perfect, or it runs like crap.  I was playing with it in the garage yesterday, and it was running pretty flawlessly for about half an hour while I was tinkering.  Then I decided to take it up the street, and it ran great up the driveway.  I got to the end of the driveway, and it's like someone flipped a switch, and it instantly started running poorly again.

I have brand new NGK plugs in it, but I'll try swapping the front one since I got 4 plugs the other day.

[Superfly]

The 83 carbs rock.  I love mine.  Sometimes it will take an additional cleaning to get them perfectly clean.  but you said you let them soak for 2 days.  that is a bit long, and depending on the solvent, it could eat the rubber gaskets after that length of time.  But you problem sounds electrical...

What you are going thru is pretty typical when you revive a Vision from a long sleep (at least it has happened when I have revived one) try this... on the 6 prong plug that connects to the TCI, grab a pair of needle nose plyers, and pull out 2 wires from the plug,

1 The Yellow/ Black stripe (Rev Limiter)
2 The Black/ white stripe (side stand switch)

**note these are safety features, which you can re-attach if you want to**

Then go thru every electrical connection & clean them, paying close attention to the coils/ low voltage connections.  If the same cylinder keeps on cutting out after you disabled the safteys, switch the coils, and see if the same cylinder goes out, this will help narrow down the gremlin.

[Lucky]

'Cmon Guys! 6 replys to get it right? we are slipping!!

Cut the rev limiter wire.

the tip off was in the first post: the rear cyl is dying & the tach is acting up. that's all you needed to know.

--Lucky

[Extent]

But he said it only consistantly runs on the rear cyl.  With the bike running if he pulls the rear plug wire it dies instantly.  He can unplug the front cyl and it won't effect it at all, so the rear must be firing.  Unless I misunderstood.

[Lucky]

so you want the Vision to make sense? that'd take the fun out of trying to diagnose it...

[Walt_M.]

Gentlemen! The rev limiter cuts out the FRONT cylinder, at least on my '83. Been there, done that.

[Night Vision]

When the bike acts up, it's like someone flipped a switch.  It either runs perfect, or it runs like crap.  I was playing with it in the garage yesterday, and it was running pretty flawlessly for about half an hour while I was tinkering.  Then I decided to take it up the street, and it ran great up the driveway.  I got to the end of the driveway, and it's like someone flipped a switch, and it instantly started running poorly again.

which way was the wind blowing?  ::)

I have had a couple similar experiences in the past even though I cut rev wire, cleaned all(?) the electrical connections and replaced the charred stator. My system charges on the high side at idle (around 14.8 sometimes 14.9 sometimes 14.6) but drops down to a steady 14.5 when rev'd to 5k rpm.

There were about two times in the past year when I had it in garage tinkering, running nice.... all of a sudden.... poop  >:(
When that was happening, I put the volt meter on and the voltage was around 12.8... weird.. that's what Extent said

I have since clean that ground on the left coil (that I missed before) That seemed to clear up my intermittent "delayed action" on the starter button... and hopefully that mystery voltage drop / poopy running

The other thing it may be is a cantankerous TCI... 25 year old solder joints and vibration can't be good companions....
Then again.. it could always be something else  ;)

If you get the chance to replicate the problem, quickly check the voltage output.

[Lucky]

Gentlemen! The rev limiter cuts out the FRONT cylinder, at least on my '83. Been there, done that.

SUPPOSED to, but i've found that's not allways true, i've had it cut the rear cyl too. perhaps that tci signal wire was attached to the rear coil on some models (wire harness design change perhaps for some unknown reason)

also, if it's rear cyl, then it's 'rear' specific.  if it's mostly an idle problem, check the rear fuel pilot under the carb. the tach may be cutting out & that could be coincidence, it happens

[ziggy682]

Okay, so I cut the yellow/black rev limit wire, and nothing changed.  I went through and cleaned every electrical connection and the three grounds I found.  There was the main ground from the battery cable, the ground underneath the left coil, and the ground for the water temp sensors on that coolant block thing.  I did find one melted connector.  Where the r/r connects to the main harness, the black (ground, I'm guessing) wire was melted pretty bad at the connector.  I cut that connector out, and soldered it straight to the harness.  I also tried swapping spark plugs in the front cylinder.  All of this didn't effect the bike at all.  I haven't tried swapping the coils yet, so I will try that today.  I noticed the 30 amp main fuse in the fuse block gets very hot.  I will be replacing those fuses with blade type fuses soon.  I also tested the stator, and it is definitely bad.  It is grounding to the chasis of the bike, but from what I've heard, the bike should be able to run off of the battery only.  To clarify, the bike is just running on the rear cylinder 90% of the time, then it will just sort of click, and run on both cylinders for a bit, then go back to just running on the rear.

[haunter]

Okay, so I cut the yellow/black rev limit wire, and nothing changed.  I went through and cleaned every electrical connection and the three grounds I found.  There was the main ground from the battery cable, the ground underneath the left coil, and the ground for the water temp sensors on that coolant block thing.  I did find one melted connector.  Where the r/r connects to the main harness, the black (ground, I'm guessing) wire was melted pretty bad at the connector.  I cut that connector out, and soldered it straight to the harness.  I also tried swapping spark plugs in the front cylinder.  All of this didn't effect the bike at all.  I haven't tried swapping the coils yet, so I will try that today.  I noticed the 30 amp main fuse in the fuse block gets very hot.  I will be replacing those fuses with blade type fuses soon.  I also tested the stator, and it is definitely bad.  It is grounding to the chasis of the bike, but from what I've heard, the bike should be able to run off of the battery only.  To clarify, the bike is just running on the rear cylinder 90% of the time, then it will just sort of click, and run on both cylinders for a bit, then go back to just running on the rear.

mines doing stuff like that, after i fubar'd my TCI

[ziggy682]

Okay, so I figure out the problem.  It's actually not spark-related at all, it's a fuel issue like a few of you suggested.  I was looking at spark problems, since it seemed to come and go so suddenly.  It ends up that fuel isn't getting to the front carb fast enough.  I drained the front carb, turned the petcock to prime, and gas just dribbles out very slowly.  With the petcock set to "ON", it would burn the fuel faster than the carb would refill itself, so it wouldn't get any fuel.  I set the petcock to "Prime", and waited for about 10 minutes to be sure that the carb was full of gas.  Started right up, and ran like a champ.

So now, what do I need to clean in the front carb so that the gas will flow to it fast enough?

Mike

[Extent]

Dip it again, maybe check the fuel pump or the lines leading out of the fuel pump for blockage.

[Lucky]

a lot of the time a tank that looks good from the filler hole or only with slight surface rust there can have sludge built up in the low corners and around the petcock. the 'filter screen' on the petcock is useless.  pull the petcock & see if it's dirty, if so take it apart & clean it & the tank (por-15). hopefully you have a fuel filter.......