Topic: 79' CB750 K8 - Rookie questions

[MrJey]

Hi there,
my never ending CB750K8 SOHC project slowly catches up momentum and I'm about to approach the electrical issues with the build.
The idea for this bike is a clean looking 750 where the gas and oil tank as well as the battery and other electrical things are hidden underneath a glass/carbon fiber skin. (see attachement)

The skin is ready and I have to start finding space for everything. Goal is to be left with more than a 1/4 gallon gas tank 

Long story short, I need some help with the electronics and hope you guys can help me with finding the right parts.

Problem 1 - Battery:
Ideally I can find something very small like the AG-401 and still be able to use the electric starter. If there is no way, I will take out the starter.
Would it be possible to run two AG-401 in parallel to get more cranking-AMPs out of it?
How do you guys feel about a Lithium battery without a BMS?
Ar there any better alternatives?
What other components do I need?
If I remember correctly, Lithium batteries are not in favor of fluctuations in voltage!?


Problem 2 - Ignition, alternator, etc
Are there any modern upgrades for it?
Which ones would you recommend?


Problem 3 - Microcontroller Motogadget/Denali/etc
If I understood it correctly the Motogadget M-Unit replaces relays and fuses!? Is it generally speaking a good solution? Not too worried about the price but how much space do I really safe with it?
How does it perform on an older bike?
I'm designing my own front and rear light with LED's.
Any better alternatives?
What other parts do I need?


Generally speaking, the main goal is to save space, weight, and make it cleaner. Cost is secondary.

Cheers,
Tom

[Alan F.]

With cost being a secondary consideration I'm sure you can make good progress.

Have a look at these:

Wet sump conversion:
http://forums.sohc4.net/index.php/topic,169468.msg1966688.html#msg1966688

CB750A stator and field coil conversion:
http://forums.sohc4.net/index.php/topic,161381.msg1853601.html#msg1853601

Small battery info:
http://forums.sohc4.net/index.php/topic,51809.msg552428.html#msg552428

We have an entire M-unit section:
http://forums.sohc4.net/index.php/board,185.0.html

[MrJey]

Thanks for your feedback! I was already sold on the Sumpthing but when I modeled it up in my CAD model, I realized it interferes with the exhaust. Current idea is to make a rather small external oil tank and build a smaller version of the Sumpthing so at the end, the exhaust will clear and I have enough oil in the engine.

Thanks for the other links. I decided to go with a M_Unit.

Going on back to the battery question, how big of a battery should I use if I only start with my kickstarter? Could I use two batteries parallel? Also, from my understanding the original alternator would supply too much current for a smaller battery. Might be a dumb question, but do I need a different alternator or would a regulator solve this issue?

Thanks,
Tom

[Alan F.]

That's one function of a regulator on a bike, to control charging.
Why not design an exhaust that will allow the sumpthing?