Riders Of Vision

General => TechTalk => Topic started by: arthurdent510 on August 23, 2009, 01:12:26 PM

Title: Tach acted up, then bike died
Post by: arthurdent510 on August 23, 2009, 01:12:26 PM
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?
Title: Re: Tach acted up, then bike died
Post by: YellowJacket! on August 23, 2009, 02:01:33 PM
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
Title: Re: Tach acted up, then bike died
Post by: Tiger on August 23, 2009, 02:05:21 PM
 :) 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)
Title: Re: Tach acted up, then bike died
Post by: vadasz1 on August 23, 2009, 02:07:52 PM
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
Title: Re: Tach acted up, then bike died
Post by: arthurdent510 on August 23, 2009, 02:11:18 PM
I actually forgot to mention, the rev limiter was already cut when I got the bike...  It was cut going out of the tci.
Title: Re: Tach acted up, then bike died
Post by: YellowJacket! on August 23, 2009, 03:05:38 PM
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
Title: Re: Tach acted up, then bike died
Post by: arthurdent510 on August 23, 2009, 03:11:31 PM
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?
Title: Re: Tach acted up, then bike died
Post by: Tiger on August 23, 2009, 05:41:29 PM
 :) 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)
Title: Re: Tach acted up, then bike died
Post by: YellowJacket! on August 23, 2009, 08:55:10 PM
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
Title: Re: Tach acted up, then bike died
Post by: Rick G on August 25, 2009, 02:28:14 AM
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
Title: Re: Tach acted up, then bike died
Post by: arthurdent510 on August 25, 2009, 12:43:38 PM
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.
Title: Re: Tach acted up, then bike died
Post by: Lucky on August 25, 2009, 04:34:11 PM
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
Title: Re: Tach acted up, then bike died
Post by: arthurdent510 on August 25, 2009, 05:04:20 PM
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...
Title: Re: Tach acted up, then bike died
Post by: Night Vision on August 25, 2009, 07:35:39 PM
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



Title: Re: Tach acted up, then bike died
Post by: QBS on August 26, 2009, 09:28:26 AM
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.
Title: Re: Tach acted up, then bike died
Post by: jasonm. on August 27, 2009, 05:39:29 PM
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?
Title: Re: Tach acted up, then bike died
Post by: Night Vision on August 27, 2009, 07:52:43 PM
Quote from: jasonm. on August 27, 2009, 05:39:29 PM

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   :-\

Quote from: arthurdent510 on August 25, 2009, 12:43:38 PM
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.
Title: Read QBS again, and think it through
Post by: Coil Coyle on August 27, 2009, 07:58:13 PM
Quote from: QBS on August 26, 2009, 09:28:26 AM
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
Title: Re: Tach acted up, then bike died
Post by: arthurdent510 on August 27, 2009, 08:05:55 PM
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...
Title: Re: Tach acted up, then bike died
Post by: Coil Coyle on August 27, 2009, 08:52:01 PM
Quote from: arthurdent510 on August 27, 2009, 08:05:55 PM
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
Title: Re: Tach acted up, then bike died
Post by: arthurdent510 on August 29, 2009, 10:25:10 PM
Ok, pulled the drain plugs off, looks like both carbs had plenty of fuel in them.  Borrowed a spark tester from a buddy of mine, both front and back are giving good spark.  So I pulled the spark plugs... front plug looked fine.  Pulled the back plug and it was full of oil.....  Do I have some bad rings, bad head gasket, or something of the sort?
Title: Re: Tach acted up, then bike died
Post by: akvision on August 29, 2009, 10:56:21 PM
Does not sound good.   Sorry to hear.
Winter is here and the V Grems didn't want you to get bored??
:-\
Title: Re: Tach acted up, then bike died
Post by: arthurdent510 on August 29, 2009, 11:09:44 PM
Bah, winter is the best time to ride in az!  Was looking forward to it...  guess I know what I'm going to be doing next weekend...  Rick and I just replaced the head gasket on both cylinders around the beginning of the year too.   :-\
Title: Re: Tach acted up, then bike died
Post by: arthurdent510 on August 30, 2009, 10:10:45 PM
Ok, did a compression test this evening, and the rear cylinder came in at about 120psi.  So it looks like the head gasket is still well.  Next culprit would be the valve seals?
Title: Re: Tach acted up, then bike died
Post by: jasonm. on September 06, 2009, 07:17:25 PM
when you changed the head gaskets. Did you change the associated O-Rings that reside with them on the studs???  My tach always has done a 5-6k wave from time to time. I was sayinig before...my tach went dead and then ran on one cylinder. Replace the ignitor in 2 minutes and fixed. Done 150-200 miles since and no more badness.