I upgraded my rectifier on my bike using the radioshack rectifier upgrade, which i've used on both my bikes, and was very happy with it. however, I am only running a 4ah battery on one of my bikes and didn't want to trust the stock regulator to keep my battery from being cooked, so i started looking at upgrades.

I saw the single unit upgrades from charlies place and oregon parts, but they are bit out of my price range. I noticed that one of the units was identical to a reg/rect I had installed into an old riding mower. that unit had only cost me $45, so I started looking at those. after a bit more research I found a good, small unit. I was lucky and got mine in an auction for $10, however all the other units i've seen online sell for right around $25-30.

the unit is typically used for Kohler or John deere engines, its rated for a 12v15a system. these honda twins (as far as i know) only get about as high as 8a, so the 15a is plenty.

here's a link to one example.

http://www.ebay.com/itm/REGULATOR-RECTI ... 1881wt_568

the kohler part number is 25-755-03

now for those of you who have already upgraded to the radio shack rectifier, installing this will be a breeze, as it only has three terminals. AC1(yellow) AC2(pink) and battery+ (red or red/white) and it grounds out through frame, or you could bolt it on using a ring terminal. basically you just unplug the radio shack unit from the wiring, plug this one in, and remove the stock regulator.

here's a comparison shot.


and here's a shot of my wiring.


now, the hard part will be mounting it. for me, I installed this on my cafe 500t, so it was all custom mounted anyway. I would think it could almost be mounted where the stock regulator went however, only being bolted on with one bolt.

and while i installed this on my 500t, it will work for all honda twins with a 12v system and this kind of charging system

I will be following suit shortly, I'm adding one into my 450 project since its time to start working on the wiring. Thanks for writeup.

aaand bookmarked. Thanks for the heads up!

Any updates on how it works? I constructed mine as follows.

Took the stock mount for the rectifier and BENT the ears down to give a nice flat spot. I tried the original mount area for the regulator under the battery box but the holes wouldn't match up and the new unit was just barely too long and would have gotten into the air filter rubbers as well. SO I just glued a couple of bolts in those two holes.




I then tested the old holes and found that if I mounted it with them the new unit would run into the fender and the frame brace so I cut the excess ears off and drilled new holes higher in the mount.





Fits pretty well, have not got my bike running yet so I've yet to see if it works.

Test fit again with new wires, I am using the rectifier harness as well, I did ground the green to the unit.



And here it is ready to go in


I have yet to get the bike running so I don't know if it works but it is pretty simple to install. I did rework my wiring harness to remove the regulator wiring as well.

seems to work great so far. i've put probably over 100 miles on the bike since then and the battery hasn't needed charging or maintenence, so its keeping it right in the voltage range.

also, nice mod on the stock mounting spot, that looks perfect. I was wondering how to get that in there neatly with the back mounted terminals, but that looks like the way to go.

Very interesting. This may make it onto the bike as I am trying to hide the electrics.

When I redo my electrical (hopefully this winter), I'll be using this. Heck, I may put it on there sooner, with as terrible as the stock charging is on these!

I'm having to tear into my 360 here soon, she's having a carb issue that will make me have to remove the radio shack rectifier conversion to get to it. I will be moving it over to one of these shortly I think.

Possibly a stupid question, but as I'm a novice (at best)... What do you do with the old regulator wires?

I prematurely replaced my rectifier, thinking I could replace the regulator just as easily... but no one sells a stand alone replacement regualtor for the old RS21 that was on the bike.

So what is the benefit of running this one instead of the Radio Shack one? Is it mainly for when running a low ah battery?