78 CB750 F3 Barebones Startup Requirements

[belmont]

I have a 78 CB750 F3 i am in the early stages of bringing back. I have the motor in the frame, everything else has been taken off. I tested the compression with a harbor freight compression tester, so who knows how accurate it is. C1=71psi, C2=75psi, C3=90psi, C4=50psi, after a little research these numbers are low. I am currently soaking the cylinders with hoping the rings are stuck. I will test again after a good soak. If that doesn't do it I will be cracking the motor open and doing some repair/maintenace.

My real question is what is the minimum electric setup to get the motor to start and run for a bit? Any other tips on order of operation to bring an older motor back to life would be appreciated.

 

[Sonreir]

Post moved to electrical section.

 

[Sonreir]

Just to get it running (as a test) you can run a couple of wires from the positive terminal of the battery to the black/white (or sometimes solid black) wire on the coils. Job done.

Don't leave it connected for too long without the engine running or you might cook the coils.

 

[Sonreir]

Oh yeah... and make sure the other two wires on the coils (usually blue and yellow) are connected to the points.

 

[belmont]

Thanks for the move and info. I will give that a shot!

 

[duggyb]

Re: Re: 78 CB750 F3 Barebones Startup Requirements

Oh yeah... and make sure the other two wires on the coils (usually blue and yellow) are connected to the points.

Sorry to hijack thread but would this roughly be the same for my Cj360 as well sonreir?

Im Going to be firing mine bare bones as well and I would like to try and get it running on its old electronics before I wire in my Kohler regulator and antigravity battery

Sent from my SGH-I337M using Tapatalk

 

[Sonreir]

Yeah... the method listed above will work for nearly any bike with points. Just run power from the battery directly to the coils.

 

[firebane]

Yeah... the method listed above will work for nearly any bike with points. Just run power from the battery directly to the coils.

Also helps to throw a toggle switch inbetween so you can kill the bike if need be.