Tach acted up, then bike died

[arthurdent510]

Ok, so took the bike out yesterday since it was actually somewhat cool in phoenix.  It started right up, but when I got down the street a bit, the tach was way off and the engine was jumping all over the place.  It started running on one cylinder, so I turned around and headed for home.  By the time I drove the block back to the garage, the tach started working right, both cylinders were firing, and everything seemed in order.  Drove it around for a little while and all was good.  Parked it for a little while then came back out and it won't start at all.  Every once in a while it will act like it's going to catch and try to fire, but it only pops once.

I had just replaced the stator and pickups, but from what I can tell all of that is working properly.  I had to do some repair work on the wires from the stator pickups, so I was figuring my fix went bad, but that all looks good.  Do I need to start looking at the coils?  Or is there something else that it could be?

[YellowJacket!]

Sounds like the rev limiter circuit.  Looking at your TCI, the top plug has a yellow wire with a black stripe.  Thats the rev limiter sensing wire.  Cut it and cover it with shrink tube, electrical tape or whatever to protect it.  You can also put a bullet plug on it in case you need (doubtful) to reconnect it.

David

[Tiger]

 :) Or...you can take the back off of the gauge cluster and disconnect it from there...That way you can check it and reconnect it if that is not the source of the problem.

If you have a spare TCI...just do a quick swap out  :-\

                    8).......TIGER....... 8)

[vadasz1]

I don't know why it is recommended to CUT a wire.  That same whire is located on the back of the instrument gauges.  Just unscrew the bolt, remove the wire and wrap some electrical tape over the ring terminal and replace the screw.  And this way you DON'T have a butchered wiring system.

Just my $0.02 worth.

vadasz1

[arthurdent510]

I actually forgot to mention, the rev limiter was already cut when I got the bike...  It was cut going out of the tci.

[YellowJacket!]

Tiger and Vadasz, Thats a good idea but I didn't know if arthur had a fairing or not which makes it a bit of a job to do.  Another suggestion to me when I had teh same problem was to use a small screwdriver to flatten thte metal tab on the pin in the molex plug to remove the pin from the plug then cover it with heat shrink.  The plug end is the easiest to acces which is why it was my first choice.

Arthur, check the connections where your plug wires go into the coils and check your plug caps too.  Make sure they're pressed in tightly.  Also check the plugs where your wiring harness connects to the coils.

Are your plug wires new or are they the original?  If they are 25+ years old, they need to be replaced.  Tiger makes EXCELLENT plug wires and it may be worth your while to get a set from him if yours are old.

David

[arthurdent510]

They are original, as far as I can tell.  Checked the plug caps and they were in good, didn't get the tank off yet to check the coils, so I guess that's the next step.  Is there a good way to test the coils to see if one has gone bad?

[Tiger]

 :) Art', check, as in switch out, your spark plug(s) first...the wild rev counter and non starting could be two separate issues. I must be honest and say that I've never known a coil go bad on a Vision...but I'm sure one has gone kaput somewhere.

                            8).......TIGER....... 8)

[YellowJacket!]

I have an extra coil.
I'd still replace the plug wires.  Mine looked OK until I looked really close at them and saw the dry rot and cracks.  While my bike still ran good with them, it runs much better now.
May not be the issue but its worth the time, effort and $ to do.
When I first started riding my Vision, one of my plug wires was not secured in the coil.  It was a real head scratcher to figure out.

David

[Rick G]

I have never had a  bad coil on a Vision, could happen , but very unlikely. I'd suspect something in the tach. rev limiter curcuit. Recheck your work on the  ignition pickups , too

[arthurdent510]

It's kinda odd, I did some work on it last night...  I pulled the tank and airbox off and dumped some gas down the carbs and it fired right up.  Put everything back together and it won't start.  The petcock is flowing just fine, and I tried bypassing the fuel pump but that didn't help.  Dumped some more gas down the carbs and let it idle enough to get some heat in the engine then put everything back together and it ran fine.  Let it sit for a few hours and tried to start it and it was a no go.  I was thinking that I had a bad connector up in front of the airbox by the coils.  So I pulled those apart and tried to clean them but it didn't seem to help. 

Any more suggestions?  Does this look like an electrical issue still?  Or do I need to start looking elsewhere?  Once it was warmed up a bit I could kill it and start it no problem and it ran great.  It was just when it was cold and no matter where I had the choke set at.

[Lucky]

if it cranks, but cranks slow it may be a charging issue, open curcit in the battery, R/R stator.

first things first, check your charging output at the battery & report back

--Lucky

[arthurdent510]

I'll check that, but my thoughts were that if it was a charging issue, why would it start fine when I pour gas straight down the carb?  Unless there's something else in there that may be affecting it that I don't know about...

[Night Vision]

she was running on one cylinder...
you put gas down her throat and she runs.......
put things back together and she won't start....
sometimes she starts/runs, sometimes she don't

intermittent sticky float needle is my guess.

the petcock can flow gas, but if the float needles are stuck, the carb(s) won't fill up with gas.
if one carb fills with gas, and the other doesn't, she'll only run on one cylinder.

next time she acts up, try this:
put the petcock on prime for a couple of minutes, twack the fuel filter a couple of times to make sure gas is flowing or that the filter is full of gas... and don't tell me you don't have a filter!

next, pull the drain hose off the tee connector and put a short piece of fuel line on the tee where the long hose going to the rear went.

using a shot glass, open the front drain screw and measure how much gas goes into the glass.
do the same to the rear carb and measure the gas..

are they equal? or is one empty or way less?

either that or try swapping TCIs

[QBS]

Another float tip:  I do this whenever I'm starting my '83 from a long nap.  #1: I always close my inline fuel valves, drain the carbs and leave the drains open when I suspect that a long nap is coming up.  Then, at wake up time, I leave the drains open and give each float bowl a gentle tap with my 12" socket drive extension.  This done to ensure that the floats and their needle valves have dropped.

Next, I open my inline fuel valves, turn the petcock to "Prime", and let a little fuel hit the floor while giving the float bowls a couple of additional taps.  Finally, I close the drains, wait a minute or so, and start the bike.

This procedure verifys fuel flow and gives the needle valves an opportunity to clear out any debris that may be stuck between their seats and float needles.

[jasonm.]

FYI...disconnecting at the instruments does not remove it completely from potential badness. You still have that wire in the harness that could cause a problem. Always disconnect at the ignitor connector. Oh , and the same thing just happened to me yesterday. My rev limiter is disconnected. So I knew the ignitor was going bad. I carry a spare. Changed it on the side of the road in 2 minutes...ALL FIXED... :D  Also how did we go from "no tach...and dead" to it's a fuel problem?

[Night Vision]

Also how did we go from "no tach...and dead" to it's a fuel problem?

because she won't start unless you pull the tank and force her to drink   :-\

I pulled the tank and airbox off and dumped some gas down the carbs and it fired right up.  Put everything back together and it won't start.  The petcock is flowing just fine, and I tried bypassing the fuel pump but that didn't help.  Dumped some more gas down the carbs and let it idle enough to get some heat in the engine then put everything back together and it ran fine.  Let it sit for a few hours and tried to start it and it was a no go. 

he might have multiple problems... my tach gets wacked once in awhile, but she always starts up.

[Coil Coyle]

Another float tip:  I do this whenever I'm starting my '83 from a long nap.  #1: I always close my inline fuel valves, drain the carbs and leave the drains open when I suspect that a long nap is coming up.  Then, at wake up time, I leave the drains open and give each float bowl a gentle tap with my 12" socket drive extension.  This done to ensure that the floats and their needle valves have dropped.

Next, I open my inline fuel valves, turn the petcock to "Prime", and let a little fuel hit the floor while giving the float bowls a couple of additional taps.  Finally, I close the drains, wait a minute or so, and start the bike.

This procedure verifies fuel flow and gives the needle valves an opportunity to clear out any debris that may be stuck between their seats and float needles.

$0.02
;)
Coil

[arthurdent510]

Coil/QBS, can you do that test with a fuel pump inline?  I wasn't sure how much the fuel pump flows when the bike isn't running...

[Coil Coyle]

Coil/QBS, can you do that test with a fuel pump inline?  I wasn't sure how much the fuel pump flows when the bike isn't running...

Use the prime position.

;)
Coil