collapse

www.dimecitycycles.com


www.restocycle.com

www.CITYLIMITMOTO.com

www.jadusmotorcycleparts.com

www.bisonmotorsports.com

www.speedmotoco.com

www.cognitomoto.com

www.townmoto.com

www.sparckmoto.com

www.Moto-Madness.com

www.pistonsociety.com

www.steeltowngarage.com


Author Topic: 81CB750c build first time here goes nothing  (Read 2631 times)

Offline Cookie

  • Posts: 583
  • God help the child who grows out of everything
Re: 81CB750c build first time here goes nothing
« Reply #10 on: Feb 22, 2017, 23:30:28 »
DOHC CB750's don't typically "break even" until about 3000rpm. Basically at anything below that you're discharging the battery.
IIRC the shop manual specifies 14v at approx 5000rpm
* Insert something witty here *

81 CB750C
84 Tempter - well, most of it...

Offline lostinmiself

  • Posts: 51
Re: 81CB750c build first time here goes nothing
« Reply #11 on: Feb 23, 2017, 00:07:37 »
Well i wont opt for the top dollar Li battery then, i dont feel like spending the money and watching it discharge down the drain in a couple months. Maybe an AGM will be more forgiving with the voltage cycles. If they can handle 40k watts being charged and discharged over and over in sound comps they can handle some rough cb750 charges ey!

http://www.dimecitycycles.com/deltran-battery-tender-lithium-battery-12v-120-cca.html

Maybe this one?
« Last Edit: Feb 23, 2017, 02:46:29 by lostinmiself »

Offline lostinmiself

  • Posts: 51
Re: 81CB750c build first time here goes nothing
« Reply #12 on: Feb 25, 2017, 19:52:48 »
Help me troubleshoot

Wired in the relay mod, just as the site i linked says. One part from coils to the relay, one part from the relay to the positive on the battery, one part from the relay to a ground, one part from the relay to the kill wire (yellow/red) leading up to the kill switch in the hand controls. When i gave it power nothing happens, the relay clicks but thats it. It clicks weather its in the run position or in the stop positions (when you press the red start button) so obviously i did something wrong. Hopefully someone can help me? I really dont know how i could have screwed it up.

Offline lostinmiself

  • Posts: 51
Re: 81CB750c build first time here goes nothing
« Reply #13 on: Feb 26, 2017, 14:47:32 »
Well even with the power from the battery to the relay disconnected the relay still clicks. I am assuming it's getting external power somewhere. Finding that I hope will help the issue, but I don't see where it would be getting power from

I'm here for a good time,  not a long time.


Offline esmoojee

  • Posts: 163
Re: 81CB750c build first time here goes nothing
« Reply #14 on: Feb 26, 2017, 20:10:44 »
You don't use the kill switch wire... you run a power line to the battery from the relay.  A line from the coil wire black/white to the relay and a wire back to the coil from the relay and a ground.  Also, look into a lucas three phase charging system. 

Offline Cookie

  • Posts: 583
  • God help the child who grows out of everything
Re: 81CB750c build first time here goes nothing
« Reply #15 on: Feb 26, 2017, 21:33:08 »
As esmoojee said, thereferring is no yellow/red wire involved. The wire from the switch that feeds the coils is white with a black stripe.

1. Remove the white/black wire from the coils, connect to the control side (pin 85 or 86) of the relay. Connect the other side of the control to ground.

2. Run your coil power wire from the battery positive terminal, (preferably through a 10A fuse) to the switched terminal (pin 30).

3. Run the remaining wire from the output side of the relay (pin 87) to the terminal on the coils that you disconnected the white/black wire from.

4. Test the system: put a test light into the wire that feeds the coils to ground. Key on run. The relay should click and the test light should light up (indicating power to the coils) with the kill switch in 'run' and click off/light go out when you flip the kill switch to either of the 'off' positions. Likewise the test light should be out when you shut off the key.
Hook up that feed wire and make some noise.

Hope this helps!
* Insert something witty here *

81 CB750C
84 Tempter - well, most of it...

Offline lostinmiself

  • Posts: 51
Re: 81CB750c build first time here goes nothing
« Reply #16 on: Feb 27, 2017, 10:36:41 »
I must have misunderstood the directions from the link, but when I get back from my meeting this morning at work I'll get back out there and rewire it. Thanks for the info gentlemen, much appreciated!

I'm here for a good time,  not a long time.


Offline lostinmiself

  • Posts: 51
Re: 81CB750c build first time here goes nothing
« Reply #17 on: Feb 28, 2017, 18:28:36 »
Got it, got spark at the plugs, ill get it all perma-wired once my plugs and wires get here in the next couple days. Thanks yall!

Offline lostinmiself

  • Posts: 51
Re: 81CB750c build first time here goes nothing
« Reply #18 on: Mar 07, 2017, 00:49:56 »
So a little update, got the bike running smoothly, ordered plugs, wires, and some velocity stacks. They sure are shiny :)

Installed everything and the starter wouldn't crank. So after some quick work with the test light i have deducted it was the starter relay solenoid. Power going in from the battery, but nothing coming out to the starter. Yet the fuse is in tact, and bi-passing it cranks no issues. Im more curious as to what would cause it to go out? Regardless ill order a replacement and be on my way hopefully. Pulled the front wheel in order to paint them.

Figured keeping the dual disks would be a wiser choice than trying to go with laced wheels. So i figured a quick rust preventative primer, and some nice gloss black might do the trick. Im not setup to use a gun yet, so rattle can should work a-ok. Also id LIKE to spring (guiltless) for some new suspension, but i think i will use what i have and get something later down the line. Came up with cutting some of the sleeve off the OE setup to give it an aftermarket look. Hopefully the paint holds up decent, its no show bike it will be ridden as much as im able to.
 
Ill be picking up a battery tomorrow on the way to work on my pops 32 ford, he had some surgery a couple weeks ago so ive been throwing that together as well in my spare time for him. I also have narrowed down my choices as to what exhaust i want to run but i have yet to hear them. I really like these they LOOK awesome but im again unsure how they will sound.


I also like carpys Exhaust 4 into 1 CB750 SOHC Yoshimura style https://carpyscaferacers.com/shop/shop-our-store/motorcycle-parts-accessories/honda-cb500-cb550-cb750-parts-upgrades/cb750-4-into-1-exhaust-sohc/
so thats where im at lately.
Cheers yall!

Offline esmoojee

  • Posts: 163
Re: 81CB750c build first time here goes nothing
« Reply #19 on: Mar 07, 2017, 10:49:46 »
I have the cycle x 4-2-1 and its nice but itís loud. I have a V&H on my nighthawk and it too is loud but not as loud as the cycle x.