Starter solenoid woes

Hi all. Well I've bought a new solenoid because the last one was bad. However this seems to be the only solenoid available for my 1980 cb750k. The connector does not fit so I've had to pull the pins out and I've no idea where each wire goes. I tried blindly connecting then by quickly touching them and ensuring they don't spark. Well this caused me more trouble as now I have no power at all...anywhere. is there a master fuse somewhere?

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The solenoids for the early 80s Hondas are funny. Two of the pins are always hot and go to the ignition switch and the regulator/rectifier. The other two pins are for the solenoid's energizing coil.

It's easy enough to identify which is which if you have a multimeter handy.

First, make sure you have a good 30A fuse in place in the solenoid.

With the multimeter set to measure resistance, we're looking for continuity between two of the pins and one of the studs on the solenoid. Measure from one stud to each pin, in turn. Two of them should have a resistance near zero and the other two should read as Open Line. If you can't get any with a low resistance, try reading from the other stud (mark off which stud you get a reading from, this will be important later).

After identifying the two pins, these will connect to the red (or red/white) wires that lead to the R/R and the ignition switch.

The other two pins are for the solenoid's energizing coil and it doesn't matter which is which. One of the pins goes to the yellow/red wire leading from the starter button and the other wire goes to the green/red wire leading to the neutral/clutch switch diode. Or, you can skip the green/red wire and ground this pin directly to the frame. This bypasses the safety equipment like the clutch switch, so that the starter motor will work in any gear, whether or not the clutch is in.

Thanks for the quick reply by the way. I've got a new 30a fuse in the solenoid and I seemed to have lost power after connecting the wrong wires. I thought I had them correctly wired, however when I push the starter button I get a dull click noise, while the headlight turns off.

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Mags said:

Thanks for the quick reply by the way. I've got a new 30a fuse in the solenoid and I seemed to have lost power after connecting the wrong wires. I thought I had them correctly wired, however when I push the starter button I get a dull click noise, while the headlight turns off.

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Possible dead battery? Put the jumper cables on from a car battery and try again.

Well it i's a fully charged battery as of yesterday. I believe I blew something in between the battery and the ignition switch. Stumped lol.

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It's possible, but unlikely.

Try jumping it from a car battery. Just for giggles.

Sonreir™ said:

It's possible, but unlikely.

Try jumping it from a car battery. Just for giggles.

Click to expand...

Ok update. I've got the wires hooked up correctly I believe. However when I push the start button I just hear the solenoid click, as you're holding it you can the internal components shift and no start.

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And on one of the studs you have the thick wire leading to the battery positive terminal and the opposite stud has the cable leading to the starter motor?

Yes, the two thicker gauge wires are going to the corresponding locations. 1 to the battery terminal, 1 to the starter. It's strange, because it clicks and you can feel it click, but no dice. I'm wondering if I bought a faulty solenoid?

Possible. Easy to test. Take a box wrench and bridge the gap between the studs. There will be a few sparks, but the engine should spin so long as the battery is good and the starter motor is working.

Sonreir™ said:

Possible. Easy to test. Take a box wrench and bridge the gap between the studs. There will be a few sparks, but the engine should spin so long as the battery is good and the starter motor is working.

Click to expand...

Oh yes this is what I've been doing since I took ownership of the bike. That's the only way to start it. The starter solenoid is brand new though. This is why im guessing it's probably a faulty solenoid

Possible, but didn't you just get a new one?

We can test it. Set your multimeter to measure resistance and put one probe on one stud of the solenoid and one probe onto the other. Have someone press the starter button and then see if the resistance drops from Open Line to near zero.