18.5 Volts across battery at 2500 RPM's?

[smoothbomber23]

Hello All.
First off I am not good with electrical systems in the least but i am trying to learn and fix my bike. The bike is a 1986 GS450L with 7500 miles on it. My old battery which was only 6 months old was shot and i didnt know why until i put a volt meter onto my new battery and got readings of over 18 volts while running. So my guess is that the battery was just being over charged and finally just died. The guy i got the bike from had it taken apart and then put it back together and i dont know exactly what he did with the electrical but there is some things that look a little jerry rigged. Also I have had a problem with the headlight blowing out at about 5000 rpms because the jolt of power to the headlamp. The nuetral light also doesnt work sometimes but if i rev the bike up to 6000 rpms quickly it will come on and stay on for a few minutes. I guess i need to figure out where all the wires should be at and how they should be connected, is there anyone who has a wiring diagram for this bike that would be willing to email it to me? Also if anyone has a picture of what the electrical should look like on the side panel underneith the little side cover that would be greatly appreciated as well. I know about the stator papers and plan to use them because my guess is the r/r needs replacing but i want to make sure that all my wires are hooked up right before i get a new one because i dont wanna destroy a new r/r. Any help or wisdom is greatly appreciated!!!
Thanks In Advance
Thomas

[Redman]

Not Good !

18 volts will overcharge battery and boil out the fluid (really not "boil" but that what people call it).

Maybe R/R is at fault, or maybe not. IF R/R black wire is not properly grounded the R/R will not function properly and voltage will be too high just like you are experienceing. I have not experience this myself, but have seen it stated here a few times. And knowing how the R/R works it makes sense to me.

The R/R black wire is typically grounded to the same bolt that the starter solenoid is bolted to battery box. So that seems like it should be a good ground, but problem can be that the battery box is not well grounded to the frame.

Good that you have a volt meter. With bike running, measure volts from that supposed graound bolt to the battery negitive. SHaould be no reading at all. If there is run a seperate ground wire from that bolt to batt neg, or do that anyway, is other reason why would be a good idea anyway.

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[Steve]

I don't have a picture for you of the wiring, but the charging system on these bikes is actually rather simple. Look for three wires that come from the stator. They usually route through the starter cavity, then up toware the r/r. These wires should plug directly into the three input wires of the r/r. One wire might make a detour into the main harness, only to re-appear back near the r/r, but this wire can be ignored, go straight from stator to r/r. The r/r should have two more wires, usually red and black. The red wire should go to the + terminal on the battery, the black wire should go to the - terminal on the battery. The black wire might be 'grounded' to the mounting plate for the r/r, but that plate is rubber-mounted and relys on another ground connection, so it's best to run the r/r black wire directly to the battery. Try those things, and then follow the rest of the suggestions in the Stator Papers, then let us know what you find.

By the way, with 18 volts, you litterally boiled the water out of the battery. It did not die because it was overcharged, it died because it was dry.

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[bubba]

I made a new ground strap out of heavy (no. 8 I think) wire, soldered lugs to both ends attached one to the RR and the other to the grounding bolt on the engine case. Make sure your contacts on the RR and the engine case are super clean and bare.
Also a Honda rr kit from duaneage on this forum might be a good idea.

[smoothbomber23]

Where on the R/R did you connect the ground wire? Also i am having trouble seeing where the black wire from the R/R is going, it doesnt go directly back to my battery box to be grounded i dont think. Also any input on why the nuetral light and headlight are doing the weird things i mentioned early would be very helpful.
Thanks

[posplayr]

links

I would not run your bike till you get the charging sorted.

http://www.thegsresources.com/_forum/showthread.php?t=140109

[smoothbomber23]

I don't intend to! That would just cost me 67 dollars every 150 miles (for the new battery) I bought the bike to save money! Thanks For the link though, but i still don't really understand it, I am electronics stupid but I'm gonna start with that.
Thanks Again

[bubba]

You would attach the new ground wire to one of the mounting bolts of the RR. I am no expert, but I think the other weird stuff may be related to this problem. Try this and see what happens, but I would still consider a Honda RR kit even if this helps. I am just going by my experience so take it for what it's worth.