Topic: CB750K2: help me minimize my electrics please!

[niels.d]

So I'm in the process of rebuilding my CB750K2, and I'm trying to minimize my electrics as much as possible. My goal with the bi9ke is to go for a stripped down and bare bones look. It will have pod filters, a brit-style cylinder oil bag, and I plan to try to tuck the electrics as much as possible under a flat brat style 2 person seat. The plan is no turn signals, brake light actuated by the rear brake only, kickstart only... I said bare bones right?

A previous owner tried to turn my bike into an all-yellow-and-flames 80s chopper and did a messy job with the electrics. I plan on going pretty much all new and have been trying to figure out exactly what components I need for the rebuild. I drew out a rough diagram, and I think I got it down, now its just making sure the parts I plan on getting are adequate, so I have a few questions. Please bear with me here guys, I'm a total newb when it comes to electronics...

The Battery
Want something small as possible but without compromising performance and reliability too much. I was thinking an Antigravity 2300 4-cell (2.5 AMP Hour, 120 CCA), that you can find at Dime City.

Would this be adequate for a kick only 750? Anything cheaper/better thats comparably small out there?

Regulator/Rectifier
I want to go for a combo unit to simplify things and make my life a bit easier. DimeCity sells one for the CBs, but at $88 it is a bit pricy. As an alternative would something like this Trail Tech universal ATV unit work? I was thinking it might be a bit more weatherproof and the pricetag is much better as well.
rockymountainatvmc.com/productDetail.do;jsessionid=2061B2B55105A6B25C59D4D59704FD6A?webCatId=20&webTypeId=88&navTitle=Electrical&navType=type&prodFamilyId=27240&stockId=223688&ref=gmc

Ignition Coils
I assume universal 12v coils you can find all over the web for $20-25 are sufficent? Anything in particular to look for?

Other then that I know I'm going to need fuses, a headlight switch, a rear brake switch, and I'm going to use a brass ignition and key from a boating store. Anything I'm missing or just general advice in reducing my bikes electrics?

[Spanner 1]

Your good for about 5 mins riding IMO before the little 2.5AH battery dies due to the headlight and ignition pulling the voltage down enough to where the field coil is receiving too little energy to produce a voltage  in the stator that is usable to charge the battery.......... anyone else ?

[lrutt]

dump starter relay, turn sig relay, hide the horn, use hand signals, pull the starter and put coils where the starter is, small Shorai LIFE battery under seat, simple toggle switch on headlight shell for hi/low, separate toggle for switch on and dump ig switch, no kill switch or simple multi switch on one side of the handlebar. Just use 1 fuse like the old bikes did and they lasted for many many years.

You can stip most everything off. The Shorai battery is extremely small and way powerful. No problems using that.

[johnrdupree]

As an alternative would something like this Trail Tech universal ATV unit work? I was thinking it might be a bit more weatherproof and the pricetag is much better as well.
rockymountainatvmc.com/productDetail.do;jsessionid=2061B2B55105A6B25C59D4D59704FD6A?webCatId=20&webTypeId=88&navTitle=Electrical&navType=type&prodFamilyId=27240&stockId=223688&ref=gmc

From the product description:
"For use in single phase applications. Does not work in dual or three phase applications"
I'm pretty sure all of the SOHC's are three phase, I know the 550 is.

~john

[Bankerdanny]

electronic ignition or points? If you are EI then you might want a more robust battery.

[cookindaddy]

No offense intended but when I hear of a "newbie in electronics" picking parts off the web to achieve a "look" I get nervous for them.

I don't have any specific advice truthfully since it is a project that I would not undertake myself and I am an EE. But then my bent is stock restoration. I think Honda engineers spent many hours and much yen getting these old bikes to have all the necessary stuff work reliably.

You do want something reliable that you will get to ride occasionally correct?

Why not just buy a good used harness for your year and just leave off connecting stuff that you think you can do without?

My .02. Good luck with your project.

[niels.d]

pull the starter and put coils where the starter is

Hmm, interesting idea, do they fit down there?

You can stip most everything off. The Shorai battery is extremely small and way powerful. No problems using that.

You seem to have the right idea of what sort of set up I'm aiming for. Anything specific to look for with Shorai batteries or any specific model you'd recommend?

From the product description:
"For use in single phase applications. Does not work in dual or three phase applications"
I'm pretty sure all of the SOHC's are three phase, I know the 550 is.

Ahh, thanks John, I'm a total electrics noob, so this is why I ask these sorts of questions! So any 12v three phase reg/rect unit should be sufficient?

electronic ignition or points? If you are EI then you might want a more robust battery.

I'm staying points for now to keep my budget down.

Any other advice would be greatly appreciated, and thanks for all your help so far, guys.

[johnrdupree]

From the product description:
"For use in single phase applications. Does not work in dual or three phase applications"
I'm pretty sure all of the SOHC's are three phase, I know the 550 is.

Ahh, thanks John, I'm a total electrics noob, so this is why I ask these sorts of questions! So any 12v three phase reg/rect unit should be sufficient?

I don't think so.  I'm about to step out of my area of expertise (if I even have one) and explain how I think the charging system works.  Hopefully someone will correct me.

Modern bikes have a 3 phase permanent magnet alternator.  That means that there are magnets (attached to the end of the crankshaft) spinning inside a set of stationary coils (the field coils, bolted to the inside of the case cover).  As long as the crank is spinning, the coils will be producing alternating current electricity.  The faster it spins, the more voltage it produces.  The alternator has three output wires, one for each phase.  These three wires go to the regulator/rectifier.  The three phase AC gets rectified (made into DC) and regulated (limited to a certain voltage) and the sent to the battery.

Our bikes have a 3 phase electromagnet alternator.  Instead of the permanent magnets producing electricity all the time, the electromagnets (the exciter coil?) only come on when the battery is low and needs a charge.  It does this by way of the regulator.  When the battery voltage drops below a certain point, the regulator turns the exciter on and the resulting magnetic field makes the field coils produce electricity.  The resulting 3 phase AC is sent to the rectifier and then on to the battery.  When the battery reaches a certain voltage, the regulator shuts off the exciter coil and the alternator stops making electricity (or makes a lot less of it).  It's probably more complicated than this, but you get the idea.

So, if I'm right (?), on our bikes, the regulator controls the input to the exciter coil where on a modern bike the regulator controls the output from the alternator itself.

So, elecro-experts, how'd I do?

~john

[cookindaddy]

Great. A perfect explanation as far as I know.

[gnarlycharlie4u]

Why hide the coils in the starter? Why not put your battery down there instead? the tank already hides the coils.

[scottly]

I have run a 3 amp-hr lead acid battery, with a stock reg/rect , H4 headlight for years with no problem.

DO NOT mount a battery in the starter area!!! The heat will drastically reduce the life of ANY battery!

[Retro Rocket]

Why hide the coils in the starter? Why not put your battery down there instead? the tank already hides the coils.

Because the heat will kill it, i wouldn't put coils there either.....

[scottly]

It just occurred to me that the starter well could be used to carry a tool-kit. Or cook biscuits?

[Retro Rocket]

It just occurred to me that the starter well could be used to carry a tool-kit. Or cook biscuits?

How about a pie or some soup for those cold winter rides....

[scottly]

Just make sure you punch a vent in the Campbell's can, so you don't end up with yucky green split-pea soup everywhere when the can explodes!!!

[Retro Rocket]

Just make sure you punch a vent in the Campbell's can, so you don't end up with yucky green split-pea soup everywhere when the can explodes!!!

Ok, how the hell did you know i love pea and ham soup.....?

[bimly]

I re-wired my bike to get rid of all the switches etc and to get shot of the twisties, tape, 3 bits of wire in one length etc left for me by the animal who owned it before.  On the bars I used a wipac / ducon BSA / Norton switch for the dip/high beam and the horn.  Starter on a 12v chrome door bell button on the side panel.  Lights on /off on a chrome toggle switch on the side panel.  Hid coils and used exposed combined rectifier /regulator.  No stock Ignition is also in side panel (key to kill).  Honda choppers web site has a definitive cartoon wiring diagram.  Do be careful, if you are not spark aware as there are dangers.  I am a domestic sparkie, but even so, I think an average DIYer with a bit of common should be ok (in my opinion).http://www.hondachopper.com/garage/simple_wiring_diagram/simple_wiring_diagram.html  try this.  Its what I used with a few mods.  If you want oil and neutral lights they can also go into the side panel (note - they are made to ground)  Good luck.

[dave500]

the electro magnet is the field,as would also be a permanant type magnetic field,the windings in the housing are the stator,the regulator switches the electro magnetic field on and off to control the output,on the permanant magnet type the excess voltage is just dumped to earth more or less

[xsmooth69x]

35 watt hid kit and led tail light boo ya my 2 cents on my superior electrical skillz on saving some watts