Honda C50

**xwhatsit** · 28th March 2009, 07:13

I've got a C50ZZ which is early 80s. Pretty hard to tell apart from the earlier 70s ones apart from things like switchblocks and seat etc.

http://www.tenavintage.com/ is the site I was talking about. Carries C70 stuff but it's all mostly identical (especially in terms of plastics).

**SARGE** · 28th March 2009, 07:22

i had a '64 C90 SuperCub as a kid .. rode it like i hated it ( keep in mind this was at the height of Evil Kenevil's fame).. took it out into the woods behind the farm.. was jumping ravines and cracked the frame in half.. left it lay where she broke .. as far as i know its still there under 30 years of accumulated leaves..

damn thing will probably still start

**foamy** · 28th March 2009, 13:21

Originally Posted by Bumblebeeman1150

Please do. I'm restoring a blue 1972 C50 and will need plastics, among other things. What year is your C50?

Mine is a 1971, red and white. I'm about to start the resto process too and need some plastic parts also.

How do I make sure its been rego'ed as a moped? Its registered and doesn't have a warrant. Is that good enough? I went on the land transport site but couldn't find any part that explained where its class would be defined by its rego details.

Steve

**xwhatsit** · 28th March 2009, 15:26

I just checked my rego label (it is registered as a moped), and it has a large capital `N' in the bottom right corner. I think that's what they do.

Alternatively, you could check the plate for free on www.carjam.co.nz

**foamy** · 28th March 2009, 19:10

Yep it turns out that the 'N' is the designation, cheers.

**foamy** · 11th April 2009, 16:49

My 1971 C50 has a problem thats becoming a real pita to solve. It will idle for two or three minutes fine and then slowly the rpms will reduce until it stalls. The idle will also alter slightly when running occasionally. I have never owned one before and so don't know too much about that whopping 5hp they possess but mine feels like it is being held back with a slight misfire under load.

I dismantled and cleaned out the carb, I have done the vacuum leak thing even making new gaskets for the carb and manifold joint. I have checked and experimented with the timing setting the points to open on, just after and before the 'F' on the cover and also checked the valve clearances. Is advancing the timing on one of these of course making the points open just before the 'F'? Also checked weird things like petrol cap breathing, fuel lines, air filter etc.

Anyway any suggestions are welcome, cheers.

**geoffm** · 11th April 2009, 19:59

Seen the workshop manual? Tried the manual links sticky?
Try http://www.hondaheaven.org/index.php?name=Sections
C90 manual is at http://www.carlsalter.com/honda-c90-manual/

**xwhatsit** · 11th April 2009, 23:02

Originally Posted by foamy

Anyway any suggestions are welcome, cheers.

It sounds just like a leak in the intake system, doesn't it! But you reckon you've taken care of that.

I read this forum a lot and one thing that regularly pops up is the throttle cable linkage. It's a simple slide-pull mechanism, no rotating lever like the more modern ones, just a cable going into the top of the carb. Apparently people have awful troubles if there's even the tiniest bit of slack in the cable; the throttle slide will stick slightly which mainly causes problems at idle.

Seems a bit silly to me (and maybe you too if you've had it apart) but I'm yet to play with the carb yet. Just finishing off the paintwork then I can start bolting it together again

Sounds a bit too simple to be the problem but you never know.

**foamy** · 12th April 2009, 10:17

Cheers for the ideas guys, have had a quick look at the throttle cable and action up at the grip. All greased and free as a bird. I have googled this until I know the hits off by heart, besides having the Haynes manual the C50 sites are now old friends.

I sat down and read the manual well last night and learnt something. Occasionally I have looked down and seen white smoke wisping out of the back of the generator/drive sprocket cover on the left of the motor. I thought without knowing the motors layout that this must be the clutch having a bad moment but the clutch is on the right and sealed up. I am guessing there is a ignition related short circuit or sick component somewhere. Also cruising around last night I noticed the engine steadily loses rpm and stalls during idle if the headlight is turned on. With irregular starting, misfiring and uneven idle its all hopefully going to add up when I take a look.

**foamy** · 25th April 2009, 00:00

Is the 70cc barrel and piston a straight swap if you have a C50? Does the head or case require machining?

Thanks if you can help.

**xwhatsit** · 25th April 2009, 01:58

I recall a discussion on this forum where this was mooted. I'm pretty sure it was possible; the 50 and 70 bottom end are very similar (narrow case design, the 6V 90 was wider until it went to 12V later on and consolidated the narrow case design). The 50 and 70 also have the same stroke, just a different bore size.

Ask on that forum, there's some pretty knowledgeable people. Just make sure you tell them it's a 6V model, it seems that 90cc 12V square headlights are the most common thing over there by far.

**marty** · 25th April 2009, 18:00

Originally Posted by foamy

My 1971 C50 has a problem thats becoming a real pita to solve. It will idle for two or three minutes fine and then slowly the rpms will reduce until it stalls. The idle will also alter slightly when running occasionally. I have never owned one before and so don't know too much about that whopping 5hp they possess but mine feels like it is being held back with a slight misfire under load.

I dismantled and cleaned out the carb, I have done the vacuum leak thing even making new gaskets for the carb and manifold joint. I have checked and experimented with the timing setting the points to open on, just after and before the 'F' on the cover and also checked the valve clearances. Is advancing the timing on one of these of course making the points open just before the 'F'? Also checked weird things like petrol cap breathing, fuel lines, air filter etc.

Anyway any suggestions are welcome, cheers.

mine does something similar - but instead it idles really fast, until decreasing enough to stop. doesn't do it when i'm riding or it's under load. i do about 60k a day on it too. i think it's probably spring tension on the slide - needs to be higher than it is, but i can't be bothered pulling it apart again

**foamy** · 26th April 2009, 00:33

Yep, fast idle then slowly reduce in increments until stalling. Its in pieces now, got all the parts gritblasted. The rebuild has begun.

Cheers for the tip on the C70, will try there.

**xwhatsit** · 26th April 2009, 01:58

Just bolted mine back together and took it for a ride -- going to need to touch up my fresh new paintwork as I chipped the hell out of the plastic shroud that fits underneath the handlebars (man, what a pain in the arse to route all the cables and plug the electrics in with that neat handlebar case thing).

But anyway, the idle is very flaky. Will idle very high -- rev it a bit and let go of the throttle and it'll near stall. Makes the autoclutch a bit dicky when coming to a stop.

Spring tension on the slide may be it. Going to strip the carb anyway in the near future, might look to see if I can find something beefier (or add some preload

).