Honda-SOHC

Could anybody in the know point me in the direction of a wiring diagram for a CB125K3.

I have tried searching but have come up blank, perhaps it’s the same as something else I could use?

Many thanks in advance.

Greg

I picked this up a few weeks ago when I got rid of the CB360, I now know that this has K0 side panels, headlight, front mudguard, tank and incorrect gauges.

The tick over was problematic as it would occasionally stick around 4k revs and stay there. There were a couple of small oil leaks as well, so I had decided to get this ready for a winter project and take some time over the darker months to see what’s what.

In typical fashion I put it in the shed on the ramp in readiness and couldn’t help prodding and poking on the odd evening and before I knew it, this had happened!




I originally thought I might do a complete restoration but with the non K2 bits replaced, that would change the look of the bike and I really like how it is. Nothing looks terrible where I’ve taken it apart and I’m very tempted to not paint or rechrome anything, more a deep clean, replace any mechanical weaknesses, seals, bushes etc and put it back together (clean and shiny) warts and all.

I guess it will find its way naturally but that’s my gut feeling, it’s only the second motorbike I’ve actually attempted any major work on so I know I will be asking plenty of questions along the way, hopefully I will remember to take more pictures, unlike this unexpected strip down.

I think that as it is already unoriginal I will make any changes that appeal to me, one being the USA bars, does anyone know where to source some decent UK style ones?

I picked up a new project bike last week, a CB350 K2 as I fancied something different to play with.

I knew it had a few things to sort, one of which is when the bike is running it ticks over fine and will rev fine and go back to tick over but it will at some point hit 4-5k revs and just stay there, it won’t drop back down, you can’t twist the throttle forward to bring it back down. If you kill the engine and start it again it will tick over fine but will stick at high revs again when revved up.   

I haven’t had it long enough to really do much and was hoping I could get some pointers before I go tearing in and set off down the wrong path. I have had a quick look in the carbs and everything seems ok at first glance, diaphragm, jets etc all seem ok. 

Any pointers as to where I might start?

I’m stripping the engine again on the CB360 this winter. I plan to split the cases and take my first look deep inside an engine. Is there anything I should be doing to the cylinder regarding storage when it’s removed, do the liners need any attention whilst removed and waiting a few months to go back on?

After getting the bike back together and running I found that I had a permanent neutral light, after my first shakedown ride I then had no neutral light, I found that if I disconnected the wire to the neutral switch and tested that, the switch was working ok. When I reconnected the wire to the switch, I had constant power to the bulb… but I had blown the bulb, easy changed and now had a permanent neutral light again.

One of the changes I made when reassembling the bike was to replace the old regulator / rectifier with a new combined unit from Common Motor.

After a bit of head scratching and wire tracing, I finally realised that I had reconnected the two 4 way connector blocks, one to the new regulator/ rectifier and the other to the stator the wrong way round!

In my defence, I am a tad colour blind and until I really peeled back the protective sheathing from the blocks I couldn’t really tell.

I now have a functioning neutral light… now I haven’t gone into it in any detail and know next to nothing but I’m surprised the bike ran like that.

Would anyone know off the top of their head any expected problems in the running of the bike with these two connectors swapped as they were?

After initially test riding the bike like that I found after  3-4 miles I started losing power, could that be a cause? I haven’t reassembled everything to test ride again yet to see if it’s better?

I have had trouble with the left side not firing a couple of times now, I have carried out some tests that I have found and hoped I could get any informed opinions before I start spending more money on stuff I don’t need.

I have carried out tests on my ignition components as per the Common Motor videos with a test light and I have tested resistance at my coils with my multimeter.

The right side that is sparking had 6.9 ohms across the two wires from the coil and 14k ohms from the plug cap back to the coil.

The left side has 4.3 ohms at the two wires and 14k ohms from the plug cap back to the coil.

Could the left coil be bad? From what I’ve read online, if it has between 3-5ohms it should be ok, any opinions?

There is a disparity between the two, almost a 3 ohm difference but could that be the cause of no spark?

The bike was running on both cylinders until I decided to take the tank off and investigate the hanging idle and erratic tick over??

I’ve had this bike down to a bare frame and bagged and tagged everything meticulously but for the life of me, I can’t find this. Everything else is present and accounted for and I’ve seen it several times, I know it was here but it has disappeared, I’ve spent days going through EVERYTHING but it’s vanished!

If anyone has one they could sell or any suggestions where I might find one it would be hugely appreciated.

Cheers

Greg

I am getting close to starting up my CB360 after stripping and reassembling, the top end has been off and rebuilt.

I know this is a basic question but it’s the first engine work I have undertaken.

I know that I need to make sure that I have oil getting to the top end but how long should this take roughly?

I don’t want to panic and convince myself there are problems too quickly but also don’t want to have it running for too long and do some damage.