Regulator Rectifier replacement

[Mcgillivray2]

Hi there, first post on this site, new owner of a GS.
I recently bought a 1982 GS400L with what I think is faulty regulator Rectifier. I'm a beginner to motorcycle maintenance/repair so don't be afraid to make break things down to me simply haha.
As I rev the engine to 5000rpms with a voltmeter on DC on the battery terminals I get readings over 17 volts. That means the reg/rec needs replacement, correct? from reading stuff it seems that people recommend the SH775, is that a good choice for my bike? I'm in Toronto, Canada, so I'm also wondering what's cheap (but works) and is available here if anyone knows any other options.
I have also checked voltage outputs from the stator wires at 5000rpm and they all are around 75V.
When I ride the motorcycle it seems to run well for a while but dies when it gets hot or possibly at certain RPMs. The bike seems to start and idle well. Would a faulty reg/rec cause the bike to die in this way or is this another issue that would need to be looked into after i change the reg/rec?
Thanks in advance!

 

[Grimly]

If your reg-rec is putting out 17V (assuming your meter is accurate), you're in real danger of blowing your ignitor, which is probably why it's spluttering and nearly giving up.
Don't ride the bike until you sort it.

 

[bonanzadave]

(assuming your meter is accurate)

Better to make sure. Check your car battery with it for 12vdc. Ground your RR directly to the battery.

 

[Mcgillivray2]

Just checked my meter on my car and it reads 12.8 so I assume it's good. I have already tested the RR grounded directly to the battery as well after reading various threads as well. Thanks for the help so far. Anyone know if I should just go ahead and get the sh 775 for this bike? Anything else i should be checking if i assume the last owner has been riding it with a bad RR?

 

[Nessism]

This one seems okay other than maybe the locking tab on one of the connectors may be cheezed off. You may want to message the seller and ask specifically about the condition of the connectors before purchase.

https://www.ebay.ca/itm/2010-CAN-AM...68d62dd:g:5mYAAOSwielea8Ot&LH_ItemCondition=4

 

[Brendan W]

+1 for checking the meter.
As the battery ages they tend to over read DC voltages.
Seen quite a few wild goose chases down to meter battery.

 

[Mcgillivray2]

Great thanks for the help so far everyone. Any other parts I should check over knowing that the RR was bad? Can it wreck other components that wouldnt be super obvious?

 

[Brendan W]

A bad R/R can fry the stator. Disconnect the three phase wires from the r/r.
Check that the resistance of each phase to ground is infinite.
Check the resistances between each of the three possible pairings of the phases.
It should be the same for all and low. About 1 Ohm.
Start the bike and check the AC voltage between pairs of phases.
All three pairings should be about 80 Volts at 5000 rpm.
Oh! I see you've done that already
75 is okay.

 

[Grimly]

Light bulbs don't like it. It's possibly shortened the life of the ones that were operating at the time.
Don't know if yours has a electronic tacho or not, and I'm supposing you don't have an automatic turn-signal cancellation unit.
Other than those items, the GSs of that era are remarkably electronics-free.

 

[Gorminrider]

The original Regulators often fail. Apart from checking the bullet connections throughout, there's little to be done except a new regulator.

You've been warned about overvoltage above. But it also dries out batteries so refill immediately and cross your fingers. It might destroy an agm battery or non-maintenance type which can't be refilled. You may also still have the "headlight loop" included in the switch circuit which partly disables the stator output when the headlight is off. This is particular to this era of Suzukis. Most people get rid of these by simply running the stator's three wires directly to the new regulator's inputs (almost always 3 yellow wires in my experience using older replacements)

Whichever regulator you buy, second hand or new, try to get a real shindegnen or a real "series" polaris type most here tout. Ebay often offers made-in China cheapies that are stated to be "replacements". These are too-often no good with the odd exception ...