Honda CT110 issues: now with added clutch shenanigans

[ellingly]

Yeah, yeah, it's not a Duc, but this is a technical section, and I reckon some of the guys here will be of more use than most other forums on the net. Hence I'm asking it here.

I've been battling for almost 3 years to rebuild a Honda CT110 I bought as a box of parts. This is actually a 1989 model, which is past the models that you guys get in the states (I think they stopped at '86 in the US), but it's really a hybrid of whatever parts I can get my hands on. It's still a classic 6V one. Because I'm not expecting anyone to know the wiring off their head, this is pretty much the wiring setup that I have harnesses for.

You'll probably want to open it up in a new tab or window so you can refer to it while I crap on about my problems.

Wiring diagram resides under here

My issue is that I don't have the headlight working, the park light working, or the tail light. The indicators work, the horn works, and the ignition switch definitely worked.

All of the wiring and switches are fine, I checked their resistances and what wires are connected as per the wiring diagram, and they're all good.

I think the issue lies in that there is a terminal on the RHS switchgear (the C2 terminal, a yellow wire) which I think should have 6V, but doesn't. This wire originates back at the alternator.

If you trace through the wiring diagram, you can see that this wire (the C2 wire) goes off to the LHS switchgear, through the high/low beam selector, off to the headlight, throught the bulb and to ground. Which indicates to me that the C2 wire definitely supplies the 6V.

Like I said before, though, this wire originates at the alternator, heads off through the main wiring harness to get hooked up to the RHS switchgear. Herein lies the rub - the factory workshop manual also says that there should be continuity between this wire on the alternator harness (when disconnected for the rest of the wiring loom) and ground (well, reistance of 0.3 to 0.5 ohms). Which kinda to me doesn't make me think that it will ever have 6V.

So what the hell am I missing, am I just with the major fail when it comes to understanding this, or is it more likely that something like the reg/rect is completely toast and I have to go digging through my parts for another one?

I'd test the reg/rect but being a lovely semiconductor it depends on the instrument you use to test it and my multimeter in diode mode doesn't work the same.

Oh, and I can't tell you if it charges fine, cause I haven't got the motor going. Which is fair enough, given it's been apart for 3 years, and not running for at least 5 more before that... and I don't have a spark plug that fits .

I guess the final question is does anyone have any advice as to the best way to work out what might be wrong, or, advice on how I should tackle it to really nail down the problem? I mean, I guess another option is the alternator is toast, and I have to buy a new one which would be a bit of a PITA but not the end of the world.

For those that want to see the rest of what I've done, which basically involved pulling the entire bike down until you couldn't disassemble it any further, then rebuilding it, check out http://www.wenga.net/ellingly/posties/ which'll show you all the other stuff. It's getting there, I'm a lot further than that webpage suggests. I just want the wiring to work before I commit to trying to start it and get the bike roadworthied...

[Popeye the Sailor]

Have you checked out Old Man Honda?

http://oldmanhonda.com/MC/MC.html

[Capo]

On some low cost motorcycles from this era, the lights ran off the alternator. i.e. engine not running  = no lights.
Just a thought, I have no experience with this model.

Took a look at the wiring diagram, it looks as tho there is a dedicated winding in the alternator for the lighting (yellow wire).
Of the other two windings,  one seems dedicated to the ignition module and the other supplies the RR.

I believe the engine has to be running for the lights to work.

[ellingly]

On some low cost motorcycles from this era, the lights ran off the alternator. i.e. engine not running  = no lights.
Just a thought, I have no experience with this model.

Took a look at the wiring diagram, it looks as tho there is a dedicated winding in the alternator for the lighting (yellow wire).
Of the other two windings,  one seems dedicated to the ignition module and the other supplies the RR.

I believe the engine has to be running for the lights to work.

Cheers, although that kinda defeats the purpose of a parking light - cause you'd have to have it running to get the park light going!

I'll try to find an appropriately sized plug (DR8ES-L; also fits a lot of lawnmowers!) and kick it in the guts.

[clubhousemotorsports]

some times they wire the parking light to the battery as well so you keep the parking light. my 65 lambretta  has a lighting coil as well and you might be dealing with a shorted lighting coil. can you find a spec for the lighting coil?

Also check continuity through your switch I see it has a headlight shut off in the schematic look there carefully.

[ellingly]

some times they wire the parking light to the battery as well so you keep the parking light. my 65 lambretta  has a lighting coil as well and you might be dealing with a shorted lighting coil. can you find a spec for the lighting coil?

Also check continuity through your switch I see it has a headlight shut off in the schematic look there carefully.

yeah, switchgear is all good. The lighting coil has resistance in spec according to the factory manual, so it might just need to be started.

On that topic, I have spark plugs, and I now have fuel. So, if the gods are smiling, it might be started today...

[ellingly]

It runs, and the lights work beautiful. Capo's advice was spot-on.

I have a few niggles to work through now, but it starts. In fact, it started third kick. It would have started second if I'd put more effort into it.

It's idling way too high (perhaps 3500 rpm instead of the usual 1400), and it has a hellish flatspot off idle. Idles much slower with the choke on - probably have an airleak somewhere. Initially it leaked fuel around the float bowl but that seemed to fix itself - probably needed to soak the sealing o-ring there in fuel first. I don't have a gear lever on it as yet, and it looks like it's in a gear. I think the centrifugal clutch isn't declutching, even when it idles slowly there's significant drag the front sprocket. I need to adjust the sprocket alignment - I am using bits from a box so it's hard to make sure everything's perfect first time. I need to make a battery box. I need to properly mount the exhaust and the

Oh, and it sprays oil out one side of the head. Bloody cheap chinese gaskets. Shoulda got a genuine Honda gasket set.

Apart from that, it's all good. Worrying is the flat spot and high idle - I may have set the pilot screw completely wrong when I rebuilt the carby, and there could well be an air leak on the intake manifold (they just use o-rings to seal). The oil leak isn't so bad, I just need some gasket-goop-in-a-tube to make a gasket that'll seal.

To prove it starts (this is the third time I'd started it, it'd run for a total of one and a half minutes at this stage. Apart from the first time, it starts beautifully first kick).

[ellingly]

Anyone here any good with centrifugal clutches?

Let's just say my clutch is, er, permanently clutched. I've tried adjusting it as per the manual, but no dice, I've always got drive to tbe back wheel. Short of pulling the bastard apart and checking that the clutch plates are flat & soaking them in oil for a while, are there any other little things I can try to get the thing to work properly?

It's the last thing I need to do before I can register it and ride it off into the sunset... at the moment I just feel like riding it off a cliff. Still, as it's been a box of parts for at least the last 3 years it's not so bad.