How to Fry two very expensive ST1100 Voltage regulator/ Rectifier units.

Joined
Mar 13, 2012
Messages
5,047
Location
soCal
Bike
'97 ST1100
STOC #
687
Hi mr buddinggeezer, do have the diagram or picture how is your bypass look a like, i just change my rectifier and the voltage going up to 15.6v with head light on and low rpm
The bypass is one way of solving the problem of the alternator overcharging the battery, but do yourself a favor and trace out where the voltage drops are happening and see if you can fix the problem at the source first. When its new and clean, the voltage drop on that line is an indicator of electrical load on the battery. The higher the load the higher the drop, which then increases the alternator output to accommodate the higher load. Depending on where you do the bypass, you're removing some or all of that load measuring capability from the system. If you run your bike bone stock with no additional electrical loads, then its probably not a big deal. But if you run higher than stock loads, then its a good idea to clue the alternator in on what's happening. I've never had to trace the path on the ST, but I've done it with other bikes and you'll usually find one or more corroded connectors that are adding too much voltage drop to the path. Usually you can trace out and clean up or replace the corroded connectors and the drop will return back to normal. If you can't seem to find and remove the drops in the path successfully, then consider the bypass option as a last resort.
 
Joined
Sep 4, 2013
Messages
8,115
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Cleveland
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2010 ST1300
I'm not sure if the 1100 uses the same connectors on the wiring harness as the 1300, but Eastern Beaver sells what they call 'hitachi' connectors that mate with the 1300's factory quartet harness. Now, EB is up front about not wanting to ship an order that is less than $100, and he charges a LOT to ship small orders. So, go in with a buddy and buy a bunch, or advertise here for someone who is buying his fusebox and relay harness. I also found some alternative sources for these connectors in the USA, (sorry, I don't remember the source now - but Google will help you). Bottom line, most sellers don't want to be bothered to sell you one $6.00 connector because it costs them the same to type the label and package it as a larger order.
 

ST1100Y

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Dec 4, 2012
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4,981
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59
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Vienna, AuSTria
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ST1100Y, ST1100R
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637
That Honda marine voltmeter sounds interesting! Anybody got a part number or source?
P/N 37420-MZ9-901, voltmeter assy
further required:
P/N 64241-MZ9-900, panel voltmeter
P/N 37425-MZ9-900, stay voltmeter
2 pcs M5 nuts
some self tapping screws (reuse the ones holding the bezel for the headlight adjuster)
some wiring to hook it up (1x instrument illumination, 1x ACC switched 12V for measuring)
 
Joined
Jul 31, 2008
Messages
749
Location
Benton, AR
Bike
1991 ST1100
STOC #
7908
Hi mr buddinggeezer, do have the diagram or picture how is your bypass look a like, i just change my rectifier and the voltage going up to 15.6v with head light on and low rpm
I don't have a diagram, but here is what you do.
the black wire on the VR/R serves two purposes, one to power the alternator magnets and the second to tell the VR/R what the systems voltage is. Splice into the black wire an ignition controlled relay with a wire directly to the positive battery post. DO NOT CUT THE BLACK WIRE, SPLICE INTO IT. I would advise the relay to be fused. The 4th 10 amp fuse from the top of the fuse box will have to be removed (ign/starter) or the engine will not turn off with the ignition key.
 
Joined
May 30, 2007
Messages
1,387
Age
72
Location
Grand Junction, Colo.
Bike
92 ST1100
The bypass is one way of solving the problem of the alternator overcharging the battery, but do yourself a favor and trace out where the voltage drops are happening and see if you can fix the problem at the source first. When its new and clean, the voltage drop on that line is an indicator of electrical load on the battery. The higher the load the higher the drop, which then increases the alternator output to accommodate the higher load. Depending on where you do the bypass, you're removing some or all of that load measuring capability from the system. If you run your bike bone stock with no additional electrical loads, then its probably not a big deal. But if you run higher than stock loads, then its a good idea to clue the alternator in on what's happening. I've never had to trace the path on the ST, but I've done it with other bikes and you'll usually find one or more corroded connectors that are adding too much voltage drop to the path. Usually you can trace out and clean up or replace the corroded connectors and the drop will return back to normal. If you can't seem to find and remove the drops in the path successfully, then consider the bypass option as a last resort.
A huge +1!..........electrical issues are gonna become more common the older these scoots get. Bypassing and jumping around the problem is NOT an option for me. Having the other 34yr.old bike in my signature has been a blessing as far as electrical issues. A blessing in the sense that I went thru ALL electrical plugins and grounds, cleaned and dielectric greased all electrical when I got the STeed 10yrs. ago knowing what may rear its ugly head. BTDT with voltage drops that ALL seem to have a common denominator, no matter what model the older bike is. It's called 'out of site. out of mind' and neglect associated with the electrical plug-ins, connections and grounds. Apparently has paid off as my 92ST has never had an overcharging scenario and is perfectly within specs. The new Exide battery was in it when I bought it and I just replaced it.....10yrs. later. Had not failed yet and still load tested within spec., but Murphy's law and a LD ride this summer prompted me to replace it.
Just has been my experience, and likely not worth a plug nickel:rolleyes:.
 
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