Reg/Rec fitting

[dorkingyam]

I have a 1976 model with, I think, separate units in both sides (look very alike). I have bought a new solid state single unit with 2 sets of cables/connector.

Any advice on replacement fitting much appreciated

Matk

 

[5twins]

The tin box with the green wire wrapped bar on the side mounted on the left side of the battery box is your regulator .....

The tin box mounted on the right side is a safety relay. The rectifier is an open air affair mounted on the bottom of the battery box.

You must be sure the solid state combo unit you got is specifically made to be used on '70-'79 models which originally had separate components. There was a similar solid state combo unit used on the '80 and later models but the regulator in it is different. It won't "plug and play" with the '70-'79 system. It sounds like you may have the correct unit because you say it came with two plugs. The later unit uses just one large plug for all the wires. If you do have the proper unit, it should simply plug into the original regulator and rectifier harness plugs.

 

[MaxPete]

Hi DY:

I’ve got a ‘76 as well and I have replaced the regulator and rectifier with the single solid state unit. It works extremely well. Under your two side covers are:

• RHS - the starter safety relay (SSR) which prevents you from engaging the starter with the engine running, and the solenoid for the starter itself. The SSR is the gold coloured sheet metal boxy thing and the solenoid is the device with the really big wire coming it and leading down to the starter.

• LHS - the voltage regulator (which you will remove and replace with the new unit); In the photo below, the voltage regulator has been removed - but you can see the two which connectors that lead to the new solid state unit mounted down low below the battery box.

....and under the battery box is the rectifier, which you will ALSO replace.

Basically, you will remove the voltage regulator and the rectifier (not easy because it is under the battery box) and wire in the new solid state unit. As I recall, there are two leads for the new unit:

• one set connects to the rectifier (which transforms the AC output from the alternator to direct current (DC) and,
• the other set of leads connects to the voltage regulator which controls the alternator output to prevent overcharging the battery.

NOTES:
1) on the rectifier lead, there are three white (or possibly yellow) wires. It doesn’t matter how these are connected since they are just the three phases of the alternator output. Simply connect them to the three white (or yellow) wires in your existing rectifier plug.
2) be sure that the chassis of the new unit (i.e. the body of it) is properly grounded to the frame of the bike with a good stout ground lead. Be sure to scrape off any paint under the connnection so that it is electrically secure. I actually drilled a small hole in one of the cooling fins on the new unit and attached a ground lead with a self-tapping screw.

Now, to mounting the new solid state unit is a bit of challenge. The ideal place is under the battery box where the rectifier used to be located - but mine wouldn’t fit there so I cobbled a mount using two 12” hose clamps and attached it to the frame right behind the engine mount under the carbs. Not too pretty but it works well. You can just see the solid state unit in the photo below.

I hope this helps you out - and welcome to XS650.com!

Pete

 

[dorkingyam]

The tin box with the green wire wrapped bar on the side mounted on the left side of the battery box is your regulator .....

The tin box mounted on the right side is a safety relay. The rectifier is an open air affair mounted on the bottom of the battery box.

You must be sure the solid state combo unit you got is specifically made to be used on '70-'79 models which originally had separate components. There was a similar solid state combo unit used on the '80 and later models but the regulator in it is different. It won't "plug and play" with the '70-'79 system. It sounds like you may have the correct unit because you say it came with two plugs. The later unit uses just one large plug for all the wires. If you do have the proper unit, it should simply plug into the original regulator and rectifier harness plugs.

Thanks. So I can just disconnect both reg and reg and replug cables into new unit? Any suggestions where it should go? Is the relay on the right side needed - can it be replaced with a modern unit?

 

[5twins]

I don't think the relay is technically needed, but I think you'll want it. It stops the starter from accidentally engaging while the motor is running. There may be a modern substitute but most of us just keep the original. It's a pretty robust unit and doesn't give much trouble. And if it does, you can usually just pop the cover off and clean it out.

As far as mounting goes, I'd say put it where ever you can best fit it, but try to allow it some cooling air, the unit can get hot.

 

[MaxPete]

Thanks. So I can just disconnect both reg and reg and replug cables into new unit? Any suggestions where it should go? Is the relay on the right side needed - can it be replaced with a modern unit?

5Twins keeps beating me to the punch!

Yes, essentially, you plug the new unit in to replace the two older units (the VR which is under the LH side cover and the rectifier which is mounted under the battery box). On the unit I bought, the wires were not inserted into the connector bodies - but that only took a few minutes. BUT - be very careful to match up the wire colours correctly or you could damage the components.

As for mounting the new solid state unit - your call but I would avoid hot or vibrating areas (not easy on an XS650 I'll admit) and make sure that the air can get to it to keep it cool. I posted a photo of my el-cheapo mount below the carbs in my earlier message.

As for the Starter Safety Relay - NO - do not remove it and NO - I doubt that it could be replaced by a modern unit.

The SSR protects that many delicate (and unobtainable) starter gears from clashing if you happen to hit the starter button while the engine is running. Some of the chopper guys who run minimal electrical systems remove it - but - I would just leave it there and let it do its job. One thing to note about the SSR is that if it is dirty/corroded or filled with mouse sh!t (like mine was - somehow) - it will prevent the bike from cranking. All you do is remove the two tiny little JIS screws that hold the cover on - and clean in there with a toothbrush and some electrical contact cleaner. Wah-La - you'll be back in business.

The JIS screws are another point worth making. Everything on a Japanese anything (car, motorcycle, camera, toaster) that looks like a Philips screw - is not a Philips screw. It is a Japanese Industrial Standard (JIS) screw and it is sufficiently different from a Philips that it will be damaged unless you use the correct JIS screwdriver. They are readily available at low cost on the web - the best brand is "Vessel" and they're identifiable by the pretty blue-green colour of the handles. If you're going to work on a Japanese bike - I strongly recommend that you get yourself a set of Vessel screwdrivers. Here is a linky to a UK site which has them for 34 UKP (seems steep to me - but oh well).
https://www.ebay.co.uk/itm/JIS-Scre...330113&hash=item27fd4dd36c:g:5ckAAOSwmCVY~LCG

 

[dorkingyam]

5Twins keeps beating me to the punch!

Yes, essentially, you plug the new unit in to replace the two older units (the VR which is under the LH side cover and the rectifier which is mounted under the battery box). On the unit I bought, the wires were not inserted into the connector bodies - but that only took a few minutes. BUT - be very careful to match up the wire colours correctly or you could damage the components.

As for mounting the new solid state unit - your call but I would avoid hot or vibrating areas (not easy on an XS650 I'll admit) and make sure that the air can get to it to keep it cool. I posted a photo of my el-cheapo mount below the carbs in my earlier message.

As for the Starter Safety Relay - NO - do not remove it and NO - I doubt that it could be replaced by a modern unit.

The SSR protects that many delicate (and unobtainable) starter gears from clashing if you happen to hit the starter button while the engine is running. Some of the chopper guys who run minimal electrical systems remove it - but - I would just leave it there and let it do its job. One thing to note about the SSR is that if it is dirty/corroded or filled with mouse sh!t (like mine was - somehow) - it will prevent the bike from cranking. All you do is remove the two tiny little JIS screws that hold the cover on - and clean in there with a toothbrush and some electrical contact cleaner. Wah-La - you'll be back in business.

The JIS screws are another point worth making. Everything on a Japanese anything (car, motorcycle, camera, toaster) that looks like a Philips screw - is not a Philips screw. It is a Japanese Industrial Standard (JIS) screw and it is sufficiently different from a Philips that it will be damaged unless you use the correct JIS screwdriver. They are readily available at low cost on the web - the best brand is "Vessel" and they're identifiable by the pretty blue-green colour of the handles. If you're going to work on a Japanese bike - I strongly recommend that you get yourself a set of Vessel screwdrivers. Here is a linky to a UK site which has them for 34 UKP (seems steep to me - but oh well).
https://www.ebay.co.uk/itm/JIS-Scre...330113&hash=item27fd4dd36c:g:5ckAAOSwmCVY~LCG

Thanks everybody

Mark