Won't rev with regulator plugged in

raimitm

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I've finally got my 1983 xs650 charging, now it won't rev. It idles fine, starts stuttering and backfiring when i rev it. The problem started while i was on the highway on my way home, the bike starts stuttering. Made it home, but now the stuttering starts in the low range rpms. Recently replaced the rotor before this happened as it had charging issues. Now its charging fine, tested the rotor again its good. When i unplug the regulator the problem is completely gone, bike revs up fine. Does this point to the pickup coils on the stator gone bad? I thought it needed a carb cleaning as i havent been able to ride much until i unplugged the regulator and it goes thru the rpms fine. Any ideas are greatly appreciated!
 
Probably a weak trigger magnet. Some members experienced the same on *new* rotors. Do a forum search on "rare earth magnet".

The last rotor i had on the bike had a very weak magnet. I was epoxying a rare earth magnet that would fly off and leave me stranded. I got that rotor from mikesxs and after contacting them they sent me another rotor thats on the bike now. The magnet is much stronger, putting a wrench up to it has a strong slap. With the side case on the slap test is weaker but mywrench is still getting pulled to the case.
 
The "slap test" checks for rotor magnetism.

What about the strength of the trigger magnet?

Otherwise, sounds like the magnetism from the rotor coil is overshadowing the trigger magnet. That could happen if the rotor is being driven hard, like from a battery that's drawing mucho charging current. Could also check the distance between the trigger magnet and the pickup coils...
 
The "slap test" checks for rotor magnetism.

What about the strength of the trigger magnet?

Otherwise, sounds like the magnetism from the rotor coil is overshadowing the trigger magnet. That could happen if the rotor is being driven hard, like from a battery that's drawing mucho charging current. Could also check the distance between the trigger magnet and the pickup coils...

The trigger magnet seems good. With the stator off I put a screwdriver up to the magnet and has a nice pull, the last one had barely any.
I'll look into the distance between the magnet and pickup coils, I could see that being a problem. I had a mechanic install the rotor because I don't have an impact wrench and couldn't get the rotor nut past the end of the threads. I noticed that he got the rotor on much further so a few threads are exposed. So there could be a bigger gap there, although I'm pretty sure thats how the rotor is supposed to be seated.
I just looked at the wires coming from the pickup coils and there is small cut in the orange wire, just enough to expose the wire. Maybe cut through one or two strands, not sure if thats enough to cause the problem but I'll try splicing in a new wire there and see if that helps.
 
I just looked at the wires coming from the pickup coils and there is small cut in the orange wire, just enough to expose the wire. Maybe cut through one or two strands, not sure if thats enough to cause the problem but I'll try splicing in a new wire there and see if that helps.
Those pickups deal in miliamps... an extremely small current. One strand of that wire would be enough to work. Just fix the insulation. Splicing might cause more problems down the road.
 
Those pickups deal in miliamps... an extremely small current. One strand of that wire would be enough to work. Just fix the insulation. Splicing might cause more problems down the road.

So I guess thats not my problem. Do you know how to test the pickup wires at the connectors?
I could try the earth magnets again, still have some. Maybe the high heat JB weld works better.
Otherwise I'm looking at the XScharge electronic ignition kit.
Does this replace the magnet / pickup system so my rotor and stator would just work to charge the bike?
 
Do you know how to test the pickup wires at the connectors?
Yeah.... but the fact that you got it to work just fine by disconnecting the charging system suggests the pickups are working just fine.
Otherwise, sounds like the magnetism from the rotor coil is overshadowing the trigger magnet. That could happen if the rotor is being driven hard, like from a battery that's drawing mucho charging current. Could also check the distance between the trigger magnet and the pickup coils...
Did you check these as 2M suggested?
Since the rotor creates it's own magnetic field, all the pickups are looking for is a change in that field as the pickup magnet passes by. Excessive charge could be drowning that out.
Here's another thought. It's a long shot but might be worth looking into since you've had this problem for awhile...
If the brown and green wires to the brushes were reversed sometime in the past, the magnetic field of the rotor would be reversed. Might be masking the pickup magnet if north and south were aligned on the rotor and magnet. Use an accurate diagram and make sure the brush block and reg/rec are wired correctly and not reversed.
 
Yeah.... but the fact that you got it to work just fine by disconnecting the charging system suggests the pickups are working just fine.

Did you check these as 2M suggested?
Since the rotor creates it's own magnetic field, all the pickups are looking for is a change in that field as the pickup magnet passes by. Excessive charge could be drowning that out.
Here's another thought. It's a long shot but might be worth looking into since you've had this problem for awhile...
If the brown and green wires to the brushes were reversed sometime in the past, the magnetic field of the rotor would be reversed. Might be masking the pickup magnet if north and south were aligned on the rotor and magnet. Use an accurate diagram and make sure the brush block and reg/rec are wired correctly and not reversed.

What would be the test or solution to excessive charge?
I recently put in a new Yuasa battery. It's been holding 12v no problem, charging no problem.
The bike goes up to 14 when I rev it and doesn't pass 14.
I can check at what rpms it reaches 14, but no idea what to do to adjust the amount of charge.
I'll look into brush wires being reversed, but the fact that the stuttering problem kicked in while on the highway and gradually got worse
makes me think something went bad in the wiring, or the overcharge idea, as I was at high RPMs when the problem started.
 
Also... are you running a stock reg/rec?
 
Also... are you running a stock reg/rec?

Yeah it's a stock one I got off ebay, I still have the stock one I had on originally. I changed it when I replaced the stator back when I was trying to get it charging. Turned out my old rotor was the problem. I'm testing my old regulator now, maybe this one I replaced is the problem? I did notice when I got it charging that it jumps to 14V very fast.
 
Every regulator can have a slightly different max set point. They're usually close to one anther, within a couple tenths of a volt, but may not be identical. I barely hit 14 on my '83 while my '78 usually gets up to 14.2 or 3. I'm thinking all the extra light bulbs on the rear may account for that. My '78 has one single combination tail light/brake light/license plate illumination bulb. The '83 has 4 freakin' bulbs back there - 2 tail/brake and 2 license plate illumination bulbs. That's got to be taxing the system more.

Yes, try your old reg/rec, and/or a test run with the current unit unplugged. I think I've read a bad one can cause issues like this.
 
.....but the fact that the stuttering problem kicked in while on the highway and gradually got worse
makes me think something went bad in the wiring, or the overcharge idea, as I was at high RPMs when the problem started.
Agreed. If it was running good and got worse while driving... prolly not reversed wiring. That sounds like the TCI box itself. Have you cleaned the connector to the box?
 
Every regulator can have a slightly different max set point. They're usually close to one anther, within a couple tenths of a volt, but may not be identical. I barely hit 14 on my '83 while my '78 usually gets up to 14.2 or 3. I'm thinking all the extra light bulbs on the rear may account for that. My '78 has one single combination tail light/brake light/license plate illumination bulb. The '83 has 4 freakin' bulbs back there - 2 tail/brake and 2 license plate illumination bulbs. That's got to be taxing the system more.

Yes, try your old reg/rec, and/or a test run with the current unit unplugged. I think I've read a bad one can cause issues like this.

Good to know, I'll report back when I try my old reg/rec.
 
Agreed. If it was running good and got worse while driving... prolly not reversed wiring. That sounds like the TCI box itself. Have you cleaned the connector to the box?

Haven't looked into the TCI box yet. Going to clean the connector and put in my old regulator and see what happens.
I'm looking at a thread about the TCI box diodes failing causing stuttering, shouldn't cost much to replace it but I can't find any on ebay.
I'll post on here for one if I don't have luck with the regulator.
 
Haven't looked into the TCI box yet. Going to clean the connector and put in my old regulator and see what happens.
I'm looking at a thread about the TCI box diodes failing causing stuttering, shouldn't cost much to replace it but I can't find any on ebay.
I'll post on here for one if I don't have luck with the regulator.
Let's hope it's the reg/rec... but if you need a TCI box, contact @gggGary
 
Let's hope it's the reg/rec... but if you need a TCI box, contact @gggGary
Let's hope it's the reg/rec... but if you need a TCI box, contact @gggGary

No luck with switching the reg/rec. I'm going to look for a TCI box, thats the only thing I haven't replaced.
Just asked gggGary if he's got one. I just don't know how the TCI system is working fine w.o reg/rec if it's the box,
but also seems unlikely both reg/rec are causing the problem. Guess I'll see what happens with the new TCI box. Connectors look clean from the box.
 
I just don't know how the TCI system is working fine w.o reg/rec if it's the box,
Yeah... wish I was hopeful the box will fix it, but it doesn't make sense does it....
About the only scenario I can think of.... the box feeds power out to the pickups and the pickups use that power to send a trigger signal back. If the box had high resistance on that power feed line for whatever reason, the current going out would be weak and the return signals would also be weak. Strong enough to work when the rotor isn't magnetized, but not when it is. I know.... it's a long shot.
 
Based on my scenario above, I suppose it's also possible the high resistance could be in the pickup itself..... contrary to my earlier post.
 
Another recent, similar thread for reference.

http://www.xs650.com/threads/shakedown-breakdown-‘83-sputtering.52377/

With respect to the charging rotor's effect on the trigger magnet and pickups, consider that the trigger signals will be reduced during strong rotor magnetism, on well-running TCI ignitions as well as the problematic ones. If your trigger magnet is strong, and running fairly close to the pickups, then it must be in the TCI where there could be a problem. Especially if the condition occurred rather quickly.

Here's a pic of a member-posted TCI circuit board.
Xonix-TCI.jpg


The upper-right quadrant is where the trigger signals enter and are conditioned, initially by passing thru diodes D1, D2, D3, D4. The two transistors, middle-right, amplify the conditioned signals and feed them to the IC to the left. Some members have successfully restored their TCI function by replacing those first 4 diodes.

The upper-left quadrant is the coil driver circuit. The large heat-sinked transistor provides the 5-6 amp grounding for the coil, thru the orange wire, grounding thru the black. That orange wire will see hundreds of volts from the coil's inductive kickback. It's very important to have solid connectivity, and good grounding on those 2 wires. Some TCIs have been successfully repaired by replacing that large driver transistor, a specialty item no longer available, have to use suitable substitutes...
 
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