Belt driven alternator set up? Pics included

they spin faster I thought. small pulley on alt large pulley on crank. the newer imports use a tiny alt. that chevy alt is huge. can we get a better picture of the other side? did you mount a sprocket to the alt?
 
If people think that a PMA system is modern and the best thing going, I have experience with a lot of old British bikes that used that system. Lucas was known as the Prince of darkness for a reason.
 
they spin faster I thought. small pulley on alt large pulley on crank. the newer imports use a tiny alt. that chevy alt is huge. can we get a better picture of the other side? did you mount a sprocket to the alt?

I mounted a sprocket from Tractor Supply to an 11/16 implement hub (the Delco 10si has an 11/16 shaft) that works with that series of sprocket, and attached it in place of the stock pulley and fan. It's a 14 tooth sprocket, and it starts charging at a little under 50 mph. I'm going to drop it to a 10 tooth and see where that puts me. Where I live, 5 minutes away from my house in any direction, the speed limit is 55mph, so it's not a huge problem. I'd like it to spin a bit faster at lower rpm's though. The alternator puts out its minimum amperage (20) at 1600 rpm at the alternator, on up to its max (63) at 6000 rpm. The Delco 10si is also only $30 at Advance Auto which helped, since this was just an experiment. There are also lots of mini alternators that are meant to be a direct replacement for this model, so the mounting "ears" are the same dimension, but the body is MUCH smaller.
 

Attachments

  • IMG_20151010_182124_742.jpg
    IMG_20151010_182124_742.jpg
    274.6 KB · Views: 244
  • IMG_20151010_182132_260.jpg
    IMG_20151010_182132_260.jpg
    284.3 KB · Views: 246
  • IMG_20151010_182143_929.jpg
    IMG_20151010_182143_929.jpg
    294.1 KB · Views: 222
  • IMG_20151010_182152_221.jpg
    IMG_20151010_182152_221.jpg
    293.2 KB · Views: 217
  • IMG_20151010_182159_113.jpg
    IMG_20151010_182159_113.jpg
    265.6 KB · Views: 237
  • IMG_20151010_182215_495.jpg
    IMG_20151010_182215_495.jpg
    283.3 KB · Views: 231
Last edited:
...It's a 14 tooth sprocket, and it starts charging at a little under 50 mph. I'm going to drop it to a 10 tooth and see where that puts me...

Just for fun, ran some numbers.
Edit: Got it all completely wrong. Forgot about primary gears.

With the 14 tooth, the alternator will be spinning around 2,000 rpm at 60 mph.

With the 10 tooth, the alternator will be spinning around 2,700 rpm at 60 mph.
With the 10 tooth, the alternator will be spinning around 2,000 rpm at 44 mph.
 
Last edited:
Just for fun, ran some numbers.

With the 14 tooth, the alternator is spinning just slightly slower than the engine when in 3rd gear.
So, it'll be spinning around 6,000 at 75 mph.

With the 10 tooth, the alternator is spinning just slightly slower than the engine when in 2rd gear.
So, it'll be spinning around 6,000 at 55 mph.

Thanks! That's the kind of info I was looking for when I started this project! I only need the alternator to spin at about 2000 rpm at 45mph. That produces between 20-30 amps which is more than I need for my kick only bike with just ignition and head/tail/brake lights for electrics.
 
If people think that a PMA system is modern and the best thing going, I have experience with a lot of old British bikes that used that system. Lucas was known as the Prince of darkness for a reason.

kisses a crucifix:yikes:
 
Edited post #64, had it all completely wrong!
Please recheck for a MAJOR revision.

Checked my calendar. Yep, sure 'nuff.


That was my "brain fart" day...
 
Kind of breaks some rules for surface area contact and number of teeth engaged. We used to say 3-5 hp to power an alternator under load, but that was with a pulley system. A chain, or a timing belt would have less drag. The crank shaft needs a certain amount of weight to absorb vibration and the centrifugal force of a rotor along with inertia helps with low end torque. It's always a trade off. In short if you eliminate the rotor from the crank shaft bad things can happen. Those pins could walk out. When it comes to gears and sprockets even numbers that divide into 360 are always easier to cut than odd numbers. I always like to see when people try something different because you never know until you try. That's interesting.
 
I would think the compact Suzuki oil cooled motor alternators would provide for some very compact and clean installations.
 
I think my mini Denso alternator pulls no more than 1.5 hp at max load. There is certainly no seat of the pants difference that I can feel. I'm not sure why anyone would mount a larger bodied unit since the little ones are good for 35-40 amps.
 
a friend of mine who has been working on yamahas for quite a few years runs a chevy alternator on his xs650. ill try to find some pics and post them here
 
I think my mini Denso alternator pulls no more than 1.5 hp at max load. There is certainly no seat of the pants difference that I can feel. I'm not sure why anyone would mount a larger bodied unit since the little ones are good for 35-40 amps.

I used that enormous Delco because it was only $30 and internally regulated. There's direct swap mini alternators that are meant to replace this one. They use the existing mounts in the cars that this alternator is designed for, so if I can make this a viable alternative to the stock charging system, I can get something with a smaller body later. This line of alternators also comes in a one wire config, and the three wire can be modified to a one wire very easily.
 
a friend of mine who has been working on yamahas for quite a few years runs a chevy alternator on his xs650. ill try to find some pics and post them here

That would be awesome. When I was putting this together, I could only find a few pics online, and no descriptions of how it all went together.
 
Last edited:
Anyone have more info on this bike and it's rad alternator set up? lol who needs a PMA conversion?
Just happened across this thread. This bike (the mosaic tank one) is sitting in a basment on the south side of Chicago. Saw it last year while checking out another roller. Looked like it has been there for some time. Its a shame
 
Just happened across this thread. This bike (the mosaic tank one) is sitting in a basment on the south side of Chicago. Saw it last year while checking out another roller. Looked like it has been there for some time. Its a shame
Interesting and sorry for the late response as I don’t post much here anymore. Not because I don’t love XS anymore. Just life happens man. I’m actually in IL, but the other end closer to St Louis.
 
Back
Top