volts seem low on 81 1000g

[455rocketv8]

Hi All - have had lots of help here on Dyna S setup - thank you all! Another question please: while looking for 12v switched power for the new Dyna S, I am finding that all of my feeds show about 10.1 - 10.2 volts. Is this normal and/or OK? So this is the tail light wire Brown, the kill switch Orange/White, the pigtails off to the old coils Orange/White from kill, Green from license light, etc. Seems like all of them. The battery is fresh, but I have been working on the bike for a while with the switch variously on and off ... showing 12.5 at the battery, starter solenoid, etc. Does this rise to closer to 12 when the bike is running? It is not running at the moment as I am replacing the ignition so I can't check. New SH775 R/R installed and when it was running on 2 cylinders (which is why I replaced the R/R because the old one caused the ignition carnage ) it was charging and regulating properly. What do you think? Thanks again - Byron

 

[Brendan W]

Ideally looking for switched feeds a half volt below battery. Usual suspects are fusebox, ignition switch, kill switch,plugs and connectors.
Keep stepping out from the battery to see where the big drop is happening, check across the fuses, look for warm fuses or bullet connectors.
At idle the system voltage should be closer to 13V rising to 14.2 - 14.4 at 5000 rpm depending on regulator cut of point.

 

[Steve]

Brendan has the right idea, but since your bike is currently not running, I will take it a step farther. :-k

Don't stress your battery. If you don't have a small trickle charger, use jumper cables, connect to a NON-RUNNING car. You can even use a lawn tractor, most of them have 12-volt batteries, too. Connect your negative meter lead to the negative terminal of the battery. Start measuring voltages at the battery, then follow the current path.

_____ Battery voltage

_____ Voltage at starter solenoid

_____ Voltage at entry side of MAIN fuse (the 'entry' side is the side that is still hot when you pull the fuse)

_____ Voltage at exit side of MAIN fuse

_____ Voltage at entry side of other fuses (solid orange wire)

_____ Voltage at exit side of each of the other three fuses

_____

_____

_____ Voltage at headlight terminals

_____ Voltage at tail light

_____ Voltage at coils (orange/white wire)

_____ Voltage at horn

_____ Votage at battery (to make sure it hasn't dropped too far)

Each of those readings gets farther down the current path and will probably be a little bit lower than the reading above it, but this will show you where you are dropping some big numbers.

Happy hunting. Don't let the smoke out.

.

 

[geol]

I think perhaps that once your electrical supply heads through the fuse box to ignition switch and splits into the sub-circuits, it goes through about a number of connectors. The stuff that goes through the kill switch that powers your coils and igniter are adding to that total. 10VDC would be about par for the course as all those 35 plus year old connectors and switches and oxidized wire add a lot of resistance. Not really much of a worry except for the coils which won't spark as well as they should on 10VDC.

 

[Brendan W]

I think perhaps that once your electrical supply heads through the fuse box to ignition switch and splits into the sub-circuits, it goes through about a number of connectors. The stuff that goes through the kill switch that powers your coils and igniter are adding to that total. 10VDC would be about par for the course as all those 35 plus year old connectors and switches and oxidized wire add a lot of resistance. Not really much of a worry except for the coils which won't spark as well as they should on 10VDC.

Mine was like that. Bit by bit I went after things. Starter turned faster, less cranking needed, started on first half turn of the crank, lights got brighter, fuses stopped blowing, throttle response got better and problems that I thought were related to carbs just disappeared. Based on that experience I would say the electrics are the bikes nervous system and you could end up wasting a lot of time on imagined issues if it isn't in the best shape it can be.

 

[geol]

Not disagreeing just noting that things will work OK without going through every connector. I also think a lot of the wire itself is adding resistance. I am sure you have pulled off a connector and noticed that dark brown wire that won't hold solder very well because it is oxidized. Farther back along the wire, the wire will be just fine and it is often better to cut the wire, splice in an equal length section of wire (probably can't find the right color(s) wire and then attach it to the remaining piece of good wire that you need to re-attach to a connector or solder. I don't like to splice in odd color wire at the ends as you soon lose track of where wires should go if you take something apart. I haven't had much luck with stuff like Deoxit cleaning terminals in a connector. Contact cleaner is a bad joke when connectors are oxidized. It is just tough to make a very old harness work as well as when it was new.

 

[Brendan W]

Agreed you can't expect the earth ( pardon the pun) from 35 year old wiring and these old beasts will soldier on at reduced voltage. I have found that in the main the connectors are the problem areas. Particularly the coil plugs which neatly hide the state of the wire inside. I spent a lot of time with small return but every so often you happen on a biggy and everything gets better after it's dealt with.

 

[posplayr]

Not disagreeing just noting that things will work OK without going through every connector. I also think a lot of the wire itself is adding resistance. I am sure you have pulled off a connector and noticed that dark brown wire that won't hold solder very well because it is oxidized. Farther back along the wire, the wire will be just fine and it is often better to cut the wire, splice in an equal length section of wire (probably can't find the right color(s) wire and then attach it to the remaining piece of good wire that you need to re-attach to a connector or solder. I don't like to splice in odd color wire at the ends as you soon lose track of where wires should go if you take something apart. I haven't had much luck with stuff like Deoxit cleaning terminals in a connector. Contact cleaner is a bad joke when connectors are oxidized. It is just tough to make a very old harness work as well as when it was new.

Deoxit is effective on somthing with just a small surface oxidation. If the wire snd contacts are heavily oxidieslzd and even green Naval jelly will clean it up quickly in about 5-10 minutes. A stainless brush helps with major crude. Once you wash and dry spray with Deoxit to preserve the bare metal. I recommend a little solder first the the Deoxit.

 

[455rocketv8]

Hey All - I can't thank you all enough - I m almost there with the ignition and the volts - HOWEVER - I need a little more help please! My starter will now not engage - it's like the kill switch is on - nothing. I of course took the igniter off since going with the Dyna ignition. There are wires from the starter button that go to the igniter - do I have an open circuit? Do I need to make some sort of jumper ?? Each time I get something right something else seems to go awry !! Thanks agian

 

[Brendan W]

Here is a wiring diagram If you haven't already found it http://members.dslextreme.com/users/bikecliff/

The starter relay has a yellow/green wire that should have 12 volts. If it not getting it go to the starter disconnect switch, probably at the clutch lever. If there is no power there go to the kill/starter switch plug and see that you are getting power at the incoming orange/white wire.
The starter relay has to be earthed to engage. Depending on how it is mounted the return current can find a way back via the battery box and frame. Sometimes it won't and you need to run a separate earth wire to ground somewhere.

 

[geol]

To reinforce some of what has been said, DO NOT ground your starter relay on the battery box. IT DOESN"T HAVE A GROUND AS THE BOX IS ISOLATED AND PAINTED. (I will not tell you how I know this). Are you holding in the clutch when you try to start? There is an interlock... yellow/green which powers from the kill switch and connects through the interlock and the yellow/green gets voltage to the starter relay to trigger it. If the clutch isn't pulled in, the circuit doesn't complete. You can bypass to test by opening your ehadlight shell and taking the wire from the kill switch which is yellow/green and plugging it into the wire going to the starter relay.

Your Dyna S needs switched 12VDC and not using the original wire that powered the IC Igniter doesn't matter as long as you have switched DC voltage.

 

[455rocketv8]

Thanks again guys ...

So - I have power on the yellow/green on top of the starter relay. Battery is fully charged. Can bridge the posts on the relay and motor turns. Was working fine until I replaced the ignition Pulling clutch does not change the situation. Big Red on relay goes to battery -big black goes to starter - I do not see a separate ground, should I run it from the post headed to the starter? I am thinking the relay went bad at some point. Particularly since I have power at the relay from the yellow/green and the starter tuns when jumping the poles. GEOL I will do the bypass test before I order a new relay ... I am just at a logic loss at the moment. Thanks again to ALL !! - Byron

To reinforce some of what has been said, DO NOT ground your starter relay on the battery box. IT DOESN"T HAVE A GROUND AS THE BOX IS ISOLATED AND PAINTED. (I will not tell you how I know this). Are you holding in the clutch when you try to start? There is an interlock... yellow/green which powers from the kill switch and connects through the interlock and the yellow/green gets voltage to the starter relay to trigger it. If the clutch isn't pulled in, the circuit doesn't complete. You can bypass to test by opening your ehadlight shell and taking the wire from the kill switch which is yellow/green and plugging it into the wire going to the starter relay.

Your Dyna S needs switched 12VDC and not using the original wire that powered the IC Igniter doesn't matter as long as you have switched DC voltage.

 

[Steve]

So - I have power on the yellow/green on top of the starter relay.

Hopefully, you only have power on that wire when you push the starter button. :-k

When you push the starter button and get power to that wire, touch your meter or test light probe to the case of the starter solenoid. If you have power there, too, you are missing the ground wire for the solenoid. There should be a wire going from one of its mounting bolts to the chassis or the battery. The solenoid is mounted on the battery holder, which is rubber-mounted to minimize vibration. It needs a separate wire to be grounded.

.

 

[455rocketv8]

Hello All - just wanted to say THANK YOU to all !! The help with setting up the relay to get good volts to the coils, the starter relay issue, the Dyna setup suggestions ... I really appreciate your help. Bike started last nite ... not done yet, but definitely in the right direction. 12 switched volts at the coils, big FAT sparks at the plugs, ignition in time, new 775 regulator is regulating, ... etc. The starter was indeed a ground - added a wire from the open pole to a good ground and all is well - I don't understand how the ground went away - thinking it must have grounded via the kill switch through the igniter somehow. Regardless, think I am at a point of tuning and fiddling and all, hopefully, will be well. Have some blown bulbs in the instrument cluster from when everything went pop and lost 3 fuses - but I can live with that for the moment. Again - thanks. Byron

 

[Brendan W]

The starter was indeed a ground - added a wire from the open pole to a good ground and all is well - I don't understand how the ground went away - thinking it must have grounded via the kill switch through the igniter somehow.

Where have you run that wire from and to ? Usually it is taken from one of the mounting screws on the relay casing.

 

[455rocketv8]

There is a small terminal screw on top of the relay with no wire on it - diagonal across from the yellow/green. Ran it to a chassis bolt that i filed paint away from. That open terminal screw an issue ?

 

[Brendan W]

There is a small terminal screw on top of the relay with no wire on it - diagonal across from the yellow/green. Ran it to a chassis bolt that i filed paint away from. That open terminal screw an issue ?

Wouldn't think so. Those small screws find their way to the casing anyway. Never seen it done that way before. Learn something new everyday. Mine is sorted because I use a relay mount screw as my single point ground or SPG.
With my limited grasp of english I had thought for one minute that you were using the starter motor terminal as the ground for the relay coil

 

[455rocketv8]

Hi Guys - I had promised an update when all was well - well ... all is not well, have a fueling issue - but the ignition and charging are GREAT! Just wanted to say thank you again for all of the ignition help - I would not be this far along without it and didn't want to grab help and disappear. Again, thank you all !