Triumph Rat Motorcycle Forums banner

1 - 20 of 21 Posts

·
Registered
Joined
·
55 Posts
Discussion Starter #1
About a month ago now the 2001 Sprint ST gave me signs of the alternator quitting. First the speedo and Tach stopped working then I needed to jump start it to get home and finally 4 miles away from home it died on the side of the road. I went home and got a battery out of a Suzuki Bandit put it in the bike started but on limp home mode (no lights) and I rode it home.

I ordered an alternator from a used parts yard put it on and no change, the bike was not charging. The yard sent me another used alternator still not charging. I had the original rebuilt. Put on the rebuilt one last night (getting really good at pulling and installing alternators) started the bike and still in limp home mode and does not seem to be charging.

The alternator for the 1999 through 2001 Sprints are basically small car alternators with the R/R incorporated in the unit. I have checked the continuity of the negative cable to the battery (OK) of the positive cable to the battery (OK) and of the ground of the R/R (OK). The gears in the bike are good. I know this 2 ways first I was able to put the bike in 6th and bump the tire to turn the engine slightly to get the receiving fins for the alternator in a more favor able position. Second when I disconnect the alternator from the battery to measure out put at idle I get ~.5 volt to ground and at 3000 RPM I get 1.7 V to ground.:confused:

Any help or ideas are greatly appreciated. Have I missed something?

Looking forward to the collective wisdom of you'all!

Burton
 

·
Registered
Joined
·
45 Posts
Burton
the ST has a 40Amp (480watt) alternator. If you are really concerned, fire up the bike and turn everything on and check the voltage at the battery - it should remain around 13.8 volts.

The only thing to bear in mind is that the alternator does not put out full output at low rpm. If you are doing a lot of city driving and running a lot of accessories, you may notice a deficit.

Bart
 

·
Premium Member
Joined
·
16,670 Posts
I've just asked for some help from the T3 forum; there are some people there who know quite a bit about these alternators.

Cheers,
-Kit
 

·
Premium Member
Joined
·
16,670 Posts
Also, shouldn't you be measuring the output with the battery hooked up?

Cheers,
-Kit
 

·
Registered
Joined
·
55 Posts
Discussion Starter #5
Battery ??

I was just thinking ... Could it be the battery? The charger seems to get it to about 13volts but no further. With the bike running the measured output is 12.1 volts.:confused:

Burton
 

·
Premium Member
Joined
·
6,462 Posts
Hi

This alternator is just the larger output version of those fitted to T3s & they are constructed similar to car alternators, but are not the 'self-exciting' type.

The ground (-tive) is the body & on T3s the engine/alternator (thick) main ground wire to battery -tive is actually mounted on one of the alternator bolts. As the starter uses this same ground, I think we can assume you have a good connection there.

The alternator output (+tive) is on the stud & (if the same as on the 1st gen T595 wiring diag I have) this goes thru' a large fuse in the fusebox to battery +. Check this fuse & associated wires/connections.

The alternator also has a smaller wire connection. This provides both battery voltage sensing & alternator rotor winding excitation supply (via the internal regulator). Without +tive voltage on this connection the alternator won't do anything. Since you've tried numerous alternators, I'm thinking this where the problem may lie.

Interestingly, on early VINs this 'excitation' feed was tapped off the ignition switch feed to the kill switch - a green wire in my T595 manual.

On VINs from 71699 the excitation feed was taken from a separate 'ign on' wire at the ign switch - a Blue/Yellow wire on the T595 diagram. I suspect your late (1st gen) ST will have this wire, as I know for a fact that this Blue/Yellow appears (unused) on ignition switches on late T3s like my 99 Legend. However, the alternator excitation wire in this version becomes Black at the point it is joined to the Blue/Yellow.

This Blue/Yellow wire goes from the ign switch to fuse #2 at the fusebox. Not sure exactly where Triumph connected the Black wire to it, but my guess would be nearer (or at) the fusebox as it's nearer to the alternator than the ign switch. (Note the other side of fuse#2 also uses the same Blue/Yellow colour, so don't get confused.)

So, look for +tive battery voltage (wrt ground) on that thin (Black?) alternator wire (with ign on). If it's not there, this is your problem. Either this wire is not connecting to the Blue/Yellow or the problem is further upstream on the Blue/Yellow or the ign switch output to it etc.

Hope this helps?
 

·
Super Moderator
Joined
·
21,256 Posts
... This Blue/Yellow wire goes from the ign switch to fuse #2 at the fusebox. Not sure exactly where Triumph connected the Black wire to it, but my guess would be nearer (or at) the fusebox as it's nearer to the alternator than the ign switch. (Note the other side of fuse#2 also uses the same Blue/Yellow colour, so don't get confused.)...
This is essentially the same on the 00-01 ST - except it's Fuse 9
But colours etc all same
Bike would have no lights or start if the feed was missing off the ignition switch to Fuse 9, so potentially there could be broken splice where the black wire connects to the blue/yellow.
If you indeed find you have no power at the black wire, then rather than try to dig through harness to find it, you might consider to run a new wire off the blue/yellow (fuse 9) at the fuse panel down to the alternator

Note that you if disconnect at the alternator, you should have 12v constant on the thick black wire; on the thin black wire, you should have 12V with key-switch to 'On'
If you validate those, and are good, then problem is internal to alternator.

 

Attachments

·
Registered
Joined
·
55 Posts
Discussion Starter #8
Thank You! I will try these experiments and fixes tonight. Right now the small black wire to the alternator is the same potential as ground. So if it is shorted to ground then I can see where is would not be getting the excitation that I need. I was wondering about that.

Thanks again for the help I will let you'all know the outcome.

Burton
 

·
Super Moderator
Joined
·
21,256 Posts
.. Right now the small black wire to the alternator is the same potential as ground. So if it is shorted to ground then I can see where is would not be getting the excitation that I need. ...
Be careful how you interpret that - measuring OV potential does not necessarily mean 'short to ground' just that there is no PD.
If it were indeed 'short to ground' it would actually blow Fuse #2 (the White Wire feed to the Key-Switch) - assuming of course that the black wire indeed actually physically connected to the Blue/Yellow wire (as intended).
i.e. more likely 'open' than 'short to ground'.

The simplest test is as I indicated, disconnect from the alternator and measure voltage wrt battery negative (ignition key-switch must be on); this should be 12V;
if you do not measure 12V, turn ignition off, then pull fuse 9 and measure for continuity between the black wire and the Fuse 9 socket. You should read 'short' to the input side of the fuse socket.
If you do not, the wire splice is presumably broken where the black connects into the blue/yellow wires.
 

·
Registered
Joined
·
55 Posts
Discussion Starter #13
Still not right

The good news is that the check engine light has gone out. The bad news is that I do not have any head or tail lights. The bike starts fine and runs fine (ohh how I miss it). I took it for a 4 mile run but still no head lights or tail lights. The fuses are OK (checked every one). I seem to be getting no voltage out of the small exciter wire to the alternator, it also seems to be grounded. I am now suspecting one or more of the relays.

I am A Mechanical engineer so my schematic reading class was 30+ years ago but it seems that the exciter is in the same circuit as the head lights. If the schematic a few posts back is for the right one. But I also see that there was a change in circuitry in the 1999-2001 run based on serial #, so my serial # is 85427 just to be precise. The parts on Bike Bandit seem to be quite different.

So my next task will be to test and potentially change out the relays.

As always any advice would be greatly appreciated!!

Burton
 

·
Super Moderator
Joined
·
21,256 Posts
That supply does not come from any relays.

Reading the schematic I linked above, your current flow goes:

Battery Positive - > Main Fuse - > Fuse # 2 - > White Wire - > Key-Switch In (White Wire) - > Key-Switch Out (Brown Wire) - > Blue/Yellow Wire - > Fuse 9

The Black Wire to the Alternator taps off the Blue/Yellow wire, somewhere between the Main Harness Connector to the Key-Switch and the Fuse Panel

That wire CANNOT be short to ground, or it would blow Fuse # 2 and your bike would not run (The same white wire to the key-switch also connects via key-switch to the ignition circuit, coming out on the Yellow Wire from Key-switch to the green wire on main harness).

It seems most likely that your ignition switch may be the problem - you are not getting output most likely broken brown wire, possibly directly at the solder pad on the switch plate itself
This is NOT uncommon problem with the key-switch.

http://www.triumphrat.net/sprint-forum/87004-bike-just-started-cutting-out-strangely.html#post1054664


* Note that the simplified schematic I posted above does not show the actual key-switch wire colours:
from the main harness side of the connector to the key-switch, the wire colours of interest are White (in) and Blue/Yellow (Out) - on the key-switch side of that connector, they are White and Brown respectively
(i.e. White remains White, Blue/Yellow connected to Brown on Key-Switch)
I added these to the original schematic for your reference.

It appears you are not getting power out on the Brown wire when the key-switch is turned on.

I've marked this up with red arrows to show you the current flow:

 

Attachments

·
Super Moderator
Joined
·
21,256 Posts
Note that since bike runs, everything up to the white wire at the key-switch can be considered good - since that also switches out to the green wire which is the actual ignition circuit.
So problem pretty much HAS to be the key-switch (pole for the brown wire), broken brown wire from key-switch, bad connection at key-switch to main harness connector.
 

·
Registered
Joined
·
55 Posts
Discussion Starter #18
DEcosse "you da man"!!!

:D It works!! I will post a complete update and analysis to help others in my position in the next few days. This forum is invaluable!!! DEcosse you were right on the money!!:)
 

·
Registered
Joined
·
55 Posts
Discussion Starter #19 (Edited)
The long sad story.

Ignition switch/charging system lessons learned.:confused:

Last summer I was on a 1500 mile tour of northern New England with my wife. On day 2 my turn signal/horn/brake light system stated to go intermittent. Since we were in the middle of nowhere we decided to push on. The 5th day I started to get stalling at below 2000 RPM It got worse and on the 6th day we did a run back home cutting our vacation short.

I noticed that the stalling symptoms got worse if I turned the handle bar. It was suggested that the wires in leading to the ignition switch may be corrupted. I took off the fairing and drilled out the security screws and disconnected the switch. I did note that the wire was zip tied in a way to put a lot of pressure on it at the steering extremes. I opened up the back end if the switch and found that the turn signal wire was broken completely and that the main ignition wire was only held by part of the insulation. The rest looked OK. I striped and soldered the wire back together then put shrink tube over top. I coiled up the wires and stuck them back in the back shell. Put everything together and rode off into the sunset.

A month later I first experienced the instruments going wonky (working and then not working). Later that day I had to jump start the bike and finally it died on the side of the road. I got home got a known good battery went back put it into the bike and rode it home but with the check engine light on. I did some investigating and found that the system was not charging.

I researched on the forum and the most immediate conclusion was that my alternator was fried. In particular the R/R, it took me a few days to figure out that the 1999-2001 955s had an automotive type of alternator. The R/R is incorporated into the alternator so you have to get a whole unit, new ($900+), used ($70-250), or rebuilt ($225).

At this point is my first down fall. The issue was what should the voltage be at the 3d wire on the alternator? One was obviously ground; one was obviously hot, feeding the battery when the bike was running. I found out much latter (weeks) that the wire is the energizer wire and should be at 12+ volts when the ignition was on. It was open, therefore not exciting the alternator with the bike going.

I got a used alternator it did not work. I got another it did not work. I got the original rebuilt, that did not work. Wrote a post to this forum titled "Help! I have gone through 3 alternators." That has the history and some very good advice and schematics.

I took DEcosse’s advice and took apart the ignition switch assembly again. The brown wire looked fine. I gave it a tug and the insulation broke the copper on the inside was severed. Fixed that, inspected all the other wires including striping one other wire which had a few broke strands fixed that one. Reinsulated all the wires with shrink tube, made a careful bundle leaving off the back cap that seemed to cause a lot of the stress using electrical tape instead.

Now 6 weeks after I broke down on the side of the road “nI’m back in the saddle again!!”:D
 

·
Registered
Joined
·
7,507 Posts
If the ignition security screws are torx security screws, you can buy the driver for these. Just for future reference. Glad to hear your saga has come to an end.
 
1 - 20 of 21 Posts
Top