Alternator swap - 1st gen bike, 2nd gen alternator?

[ldbandit76]

Actually, the heated grips aren't a problem.  I have HotGrips, Widder vest and sleeves, and have run a 100W headlight with no trouble.

But last night my Hella lights showed up.  With those across the battery, and all my other goodies turned on, I got 14.0 V at the battery, down from 14.6 unloaded (and I didn't blow a fuse).

And when I plugged in an extra H4 to check my margin, voltage dropped to 12.5.  So I'm right at the limit.  If I go back to the 100 W headlight, with the Hellas, I'll be over.  

For those that are curious, wattage totals are as follows:

Widder vest: 33W
Widder arm chaps: 20 W
Hotgrips: 30 W
Hella FF50 lights: 110 W

So that's 193 watts above the stock load (including high beam).  That's the very edge of what the first-gen alternator will handle (at 2000 RPM).  

Looks like I ought to do a write-up of the swap.  

Dave

[ldbandit76]

My second-generation Bandit 600 alternator arrived today from the UK.  It took a little over a month to get here, obviously...

After a test-fitting, it seems that the 2G alternator will indeed fit into the 1G case.  There are, however, a couple issues.

First, the 600 and 1200 use different sized gears on the ends of the alternator shaft.  Fortunately, the gear size (and part number) remains the same for the 1G and 2G versions of both models.  Thus, a gear swap will be necessary for me.  There's a cute little cush drive for the gear that makes swapping easy.  

The bolts for the 2G model are shorter than the 1G bolts.  I'll need to get new ones.  

More troublesome will be getting the wiring to match.  The 1G alternator has a cable coming out with a 2-prong spade plug on the end.  The 2G alternator has a pait of spade terminals in a small opening in the case.  Obviously, I'll need to put together my own cable.  Does anyone know where I could find a plug that looks like this (the plug from the 1G alt)?



Or a plug to fit these spades on the 2G alternator?



Also, the 2G alternator has a large screw terminal on the back side, here:



Could someone with a 2G model tell me where that wire goes?  

But, there project looks hopeful.  Other that acquiring the various pieces, it should be pretty straightforward.  More watts, here I come!

Dave

[Red01]

The wire your arrow points to on my B12 is the main power lead. The two prong plug only uses one of the two spades - the one closest to the power cable terminal.

What you could do, is try to find the 2G connector from a salvage bike, or possibly even a wrecked car that has a NipponDenso alternator.

What I'd probably do though is just crimp a good terminal end on the little wire that fits the spade and be done with it.

[ldbandit76]

I checked out the wiring diagrams for the 2G Bandits.  The screw-terminal wire seems to be on the ground/negative side (given that it's black on my new alternator).  That would mean the red, positive wire would come from the spade terminal.

Does this jibe with what you see on your bike?  

It looks like I'll just put a spade on a new lead, and graft the 1G plug onto the 2G alternator.  

Dave

[Red01]

I'll try to get a pic for ya when I get home.

[Red01]

Here ya go...



Two wires. Big one does NOT go to ground - nor does the little one, both head straight into the harness.

Pretty sure the alt gets its ground thru the case.

[ldbandit76]

That is terrifically helpful, thank you.  

I had not expected either wire to be a frame ground, just to be on the negative side of the harness.  Taking a closer look at the wiring diagram, I'm not even sure that's the case.  

But, it does look like the 1G and 2G alternators occupy basically the same spot in the harness/wiring system, so I should be able to splice in the new one easily enough.  

If not, then that big electrical fire on the horizon will be me.

I need to get that boot you have over the main power lead...

Dave

[ldbandit76]

I finished off the installation of the new alternator today.  

I had to swap gears between my old and the new one, since the new alternator was from a B6.  I grabbed the gears in a set of oak soft jaws on my vise, then took off the nut (which had been peened in place).  The cush drive is locked to the shaft, so the swap was pretty straightforward.  



The alternator drops right in place, except that I needed new bolts.  I just got some at the hardware store, rather than paying shipping for the OEM ones.  



You'll note the single spade terminal, covered in heat-shrink tubing on top, and the ring terminal on the bottom.  I spliced the old plug onto the other end of the wires, then covered the whole thing in loom.  After this picture was taken, I wrapped the ring terminal in self-vulcanizing tape.  Eventually I'll try to get a boot like the one on the starter motor, but the tape looks okay, and should hold up.  



Here's the other end of the lead, with the old plug.  Should you attempt to perform this swap, connect the ring terminal first, then this end of the lead.  Otherwise, if the ring terminal touches the (grounded) case of the alternator, you'll blow your main fuse.  You'll note the cover for my main fuse and starter relay is off.  You'll also note everything is filthy.  I gave the underseat area a good scrubbing when I was done.  

I ran three mid-point tests to check to see how things were going.  After installing the alternator, but before connecting any wires, I turned the engine with the rear wheel and watched to see if the rotor moved.  I just wanted to make sure the gear meshed properly.  I then connected a multimeter to the alternator, and spun the engine with the starter motor, with the gas shut off.  I read a small, positive voltage, so that looked good.  I then connected all the wires and fired the bike up to check voltage at the battery.  It was between 14.5 and 14.6 for most of the rev range, so that looks good, too.  

Then, since it was an unseasonably warm January day, I took a test drive.  Everything seems to work fine.  

Now I need to get my Hella lights installed, and maybe buy a few more items from Widder...

[flyguyeddy]

most alternators that have this setup work like this.  the smaller wire provides a 12 volt source for the alternator to actually charge.  an alternator cannot make power with out first recieving a small amperage source voltage.  the bigger one then is the main charge lead.  hook the big one to the battery (or wherever it goes) and the smaller one to a switched 12 volt supply.

[Slonishku]

Is everything still working well? I might to try this myself, but not until after the Cal24 in June. I don't want to play around with anything that might affect reliability before that...