Topic: New Project! 1970 CB750K1!

[newday777]

I have a fuse panel too for the K0/K1
$20

You know better than me - if I need it, let's add it in there!

You can make your own fuse if you aren't doing a show bike.

[God of Thunder]

Also - I tracked those yellow/red wires from the main area - and they seem to go into this? Can anyone identify this for me?

[God of Thunder]

I have a fuse panel too for the K0/K1
$20

You know better than me - if I need it, let's add it in there!

You can make your own fuse if you aren't doing a show bike.

For $20 - if you're willing to sell it to me, then I'm a buyer! I'd like to do everything I can to do it to the best of my abilities.

[BenelliSEI]

That last item you have from 4-1 is a combined regulator/ rectifier (two seperate parts on the original motorcycle). It looks like the connector is missing from your rectifier  (three yellow wires) so connecting it to your new harness will be a challenge.  The combination unit might be a good idea.

[God of Thunder]

That last item you have from 4-1 is a combined regulator/ rectifier (two seperate parts on the original motorcycle). It looks like the connector is missing from your rectifier  (three yellow wires) so connecting it to your new harness will be a challenge.  The combination unit might be a good idea.

This is where I need some schooling - do I currently even have a regulator and a rectifier?

[BenelliSEI]

Yes. Regulater is goldish colour, vertical on the left side of the panel. Thre wires connect to it (green, white and black). The rectifier is black, retanglar thing, held on by one stud/nut, lower right on the panel. Three of the yellow wires come from it. The 4-1 combo unit woul replace both and plugs into the new harness with no modifications.

[HondaMan]

I've got some period-correct K1 bars, yours for the postage. They were sent to me by mistake from PartsNmore.
That is one nice K1! The headlight mounting ears have been swapped to some custom holders of some kind.
My K2 (a very early one, with a K1 engine in it from Honda that way) has passed 150k miles (2 years back). I think Ofreen's F0 is past 165k now?

The plug on the wiring harness suggests it has an aftermarket harness in it. The rectangular plug for the keyswitch first appeared in the K3. The fuseholder: the K1 had one fuse in a little rubber housing that held 3 spares. The K3 harness has a 3-fuse holder. That might be a clue to which one yours has? The keyswitch for the K0-K2 has a round (brown phenolic) plug and they are nearly impossible to find now - the aftermarket ones are junk. You can get the genuine Honda keyswitch from Honda still (as of 2/2022), but the aftermarket ones (made by EMGO China) are not heavy-duty enough, despite being popular on aftermarket sites. Their problem is: they are identical to the ones for the CB/CL350 bikes of the same era, which had 8 amp contacts: the contacts get so hot while riding that the Red wire melts right off the back of the switch - in rush-hour freeway traffic (yep...).

[BenelliSEI]

Here’s a picture of my later K6. You can see the regulator and rectifier clearly. The only real difference is the fuse holder. As Mark says above, the later bikes have it mounted in the top left corner and there are three fuses in the box. Your earlier bike has only a single fuse,in the rubber case Stu offered.

That key switch Stu offered is a good one. Grab it.

[God of Thunder]

I've got some period-correct K1 bars, yours for the postage. They were sent to me by mistake from PartsNmore.
That is one nice K1! The headlight mounting ears have been swapped to some custom holders of some kind.
My K2 (a very early one, with a K1 engine in it from Honda that way) has passed 150k miles (2 years back). I think Ofreen's F0 is past 165k now?

The plug on the wiring harness suggests it has an aftermarket harness in it. The rectangular plug for the keyswitch first appeared in the K3. The fuseholder: the K1 had one fuse in a little rubber housing that held 3 spares. The K3 harness has a 3-fuse holder. That might be a clue to which one yours has? The keyswitch for the K0-K2 has a round (brown phenolic) plug and they are nearly impossible to find now - the aftermarket ones are junk. You can get the genuine Honda keyswitch from Honda still (as of 2/2022), but the aftermarket ones (made by EMGO China) are not heavy-duty enough, despite being popular on aftermarket sites. Their problem is: they are identical to the ones for the CB/CL350 bikes of the same era, which had 8 amp contacts: the contacts get so hot while riding that the Red wire melts right off the back of the switch - in rush-hour freeway traffic (yep...).

Oh...my.....gosh!! That woudl be absolutely amazing! The bars drive me crazy and I've been banging my head wanting to get new ones! I'll send you a PM!

[newday777]

Here’s a picture of my later K6. You can see the regulator and rectifier clearly. The only real difference is the fuse holder. As Mark says above, the later bikes have it mounted in the top left corner and there are three fuses in the box. Your earlier bike has only a single fuse,in the rubber case Stu offered.

That key switch Stu offered is a good one. Grab it.

He did get the switch and fuse holder. They will be mailed off tomorrow.

[newday777]

I probably have an extra used regulator and a rectifier. I'll check in the morning for them if you want to stay with the stock system.

[God of Thunder]

I probably have an extra used regulator and a rectifier. I'll check in the morning for them if you want to stay with the stock system.

I'm definitely aiming to stay as stock as possible. Still trying to learn my way around these! What I'm "hoping" for is to get a new harness, and then have the original stuff plug into it. I've got to figure out how to access the wiring on the alternator so I can update that plug!

But for now, I'm thrilled to get Stu's parts! And I'm beyond excited for HondaMan to offer up the handlebars! She'll get there!

[God of Thunder]

I've got some period-correct K1 bars, yours for the postage. They were sent to me by mistake from PartsNmore.
That is one nice K1! The headlight mounting ears have been swapped to some custom holders of some kind.
My K2 (a very early one, with a K1 engine in it from Honda that way) has passed 150k miles (2 years back). I think Ofreen's F0 is past 165k now?

The plug on the wiring harness suggests it has an aftermarket harness in it. The rectangular plug for the keyswitch first appeared in the K3. The fuseholder: the K1 had one fuse in a little rubber housing that held 3 spares. The K3 harness has a 3-fuse holder. That might be a clue to which one yours has? The keyswitch for the K0-K2 has a round (brown phenolic) plug and they are nearly impossible to find now - the aftermarket ones are junk. You can get the genuine Honda keyswitch from Honda still (as of 2/2022), but the aftermarket ones (made by EMGO China) are not heavy-duty enough, despite being popular on aftermarket sites. Their problem is: they are identical to the ones for the CB/CL350 bikes of the same era, which had 8 amp contacts: the contacts get so hot while riding that the Red wire melts right off the back of the switch - in rush-hour freeway traffic (yep...).

You can definitely see where the key switch was hacked in - as far as the fuse holder, I'll have to check! As far as the fuse holder - I'm sorry to say I'm struggling to find either a 1 or a 3! Are they not located under the side cover with the rest of the items here?

Also - I sent you a PM (I think), but I don't see it in my sent messages. Please let me know if you didn't get it as a I would absolutely love those handlebars!!

[newday777]

I probably have an extra used regulator and a rectifier. I'll check in the morning for them if you want to stay with the stock system.

I'm definitely aiming to stay as stock as possible. Still trying to learn my way around these! What I'm "hoping" for is to get a new harness, and then have the original stuff plug into it. I've got to figure out how to access the wiring on the alternator so I can update that plug!

But for now, I'm thrilled to get Stu's parts! And I'm beyond excited for HondaMan to offer up the handlebars! She'll get there!

I just tried to see your battery box electrics in the 1st post but can see you probably have a regulator and maybe a rectifier too but the bad lighting makes it hard to see.
Post a better picture of your electrics so I can see what you have. 😏

[God of Thunder]

I probably have an extra used regulator and a rectifier. I'll check in the morning for them if you want to stay with the stock system.

I'm definitely aiming to stay as stock as possible. Still trying to learn my way around these! What I'm "hoping" for is to get a new harness, and then have the original stuff plug into it. I've got to figure out how to access the wiring on the alternator so I can update that plug!

But for now, I'm thrilled to get Stu's parts! And I'm beyond excited for HondaMan to offer up the handlebars! She'll get there!

I just tried to see your battery box electrics in the 1st post but can see you probably have a regulator and maybe a rectifier too but the bad lighting makes it hard to see.
Post a better picture of your electrics so I can see what you have. 😏

Try these!

[newday777]

You have the regulator and rectifier. Clean the contacts up on them and try them with your new harness.  If they don't work then I will send you the ones I have.

[God of Thunder]

You have the regulator and rectifier. Clean the contacts up on them and try them with your new harness.  If they don't work then I will send you the ones I have.

Thanks for checking! Where would I find the fuse holder?!

[newday777]

It looks to be MIA.

[newday777]

Maybe John can take a picture of his K0 sandcast electrics.

[God of Thunder]

It looks to be MIA.

Thanks Stu for checking! It's a good thing I've got a new fuse holder on the way!

[BenelliSEI]

I’m tied up today. I’ll take a photo of the K1 tomorrow.

[God of Thunder]

Thanks so much for everyones help here! I feel like I'm finally getting somewhere! HUGE thanks to Stu for getting me that key and fuse holder! I think - and its a strong "think" that with that - this is the last two items I need to order. Stu said he may have a regulator and rectifier if I end up needing them - but I want to go ahead and replace the recitifier since the harness is (of course) hacked up on it.

Can anyone confirm if I order these two things - paired with the key and fuse and a new rectifier - I should be in decent shape wiring wise? I can't solve the no spark until I have that taken care of!

https://4into1.com/main-wiring-harness-32100-300-050-honda-cb750k-1969-1971/

https://4into1.com/alternator-wire-harness-31110-300-154-cb750-1969-1978/

[newday777]

Yes both of the harnesses are correct.

The rectifier I have has sun burnt 6 pin connector, wholebut brittle and missing the latch. It will get you going but the connector should be replaced.
I've been hunting in my boxes for a good connector and just found a usable connector and will switch it out.
The regulator is a bit rusty on the outside but is probably fine.

[newday777]

Check your regulator, see if it looks better, they don't usually go bad

[God of Thunder]

I would say my Regulator looks okay - but your Rectifier looks considerably better.....it at least has an end connector!