Vintage Honda Motorcycle Tech Forum

[Xlrator]

I got a 1975 Honda CB125S last week & want to get it running. Looking for some good tech forums I can troll for info. I found hondabikes.net (http://hondabikes.net) but couldn't find any others that have a high population like Scream & Fly. I'm looking for one that has some good vintage tech topics.

Anyone know of any?

[mike bryan]

assuming your engine has compression it will be a piece if cake to get it running. if the tank isn't real rusty put an inline filter in gas line. if tank is real rusty kreem tank (available any mc shop). carb will likely be stopped up. do not soak the whole thing yet, take it off and see if stinky varnish is in float bowl. remove floats, main jet(center of bowl area), and pilot jet and run fine wire through them until clear. blow out all passages using spray carb cleaner sparingly. set points at .014 gap and check for fire. if no compression check for tight valve. buy a 15 dollar clymer manual and dive in.
:D

[triple dude]

Mike's got you on track. For parts, besides ebay, you could go to Walneck's Bike Show/Flea Market in April up in Woodstock. Lots of Jap bike parts. There is a Japanese Bike Club but don't know there website offhand. Stop in your local 7-11 and pick up Walnecks Antique Motorcycle Trader. Look under "Clubs" and you'll find it. There's also many parts ads in there. Good luck. Should be a nice little around town bike.

[Xlrator]

Yeah, since I work only a mile from the house & every other week I could maybe get 2 months or more on a tank of gas!! Have to put Sta-Bil in every fill-up! :p I had to do everything Mike talked about and it will run and idle. Just when I put it in gear it will kill, like something's out of adjustment. I put a new clutch cable on it but need to do some more reading on the adjustment. I thought I had it.

It's not a bad-ass bike, something more for a kid. I found a picture of a newer one and it looks like mine has potential. I am planning on putting it down for something bigger.

http://oldmanhonda.com/MC/NewArchive/Pics/CB125S.jpg

[mike bryan]

the dying is probably just clutch plates stuck together. try putting it in gear without the engine running and rock the motorcycle backwards with the
clutch disengaged. if this doesn't do it wrap a bungee cord around the clutch lever in the dis-engaged position and ride it around a little. when the oil gets hot it should release.

[mike bryan]

hey which bike is yours. the top picture has a mechanical front disc brake and the bottom picture has a front drum.

[Xlrator]

Mine's the top one. Light Blue. The bottom one is an '81 or so. I like the color of the bottom one with the painted fenders and black turn signal stems. Since everything is rusted I will just change it all out to that. Make it look a little more modern.

About that clutch, that's exactly what I thought. I cleaned the oil filter and did 2 oil changes trying to flush crap out but there is still a lot of milk. I'm pulling the clutch cover off to check clutch & oil pump 'cause I hear the valves ticking like the oil isn't being pumped up there.

We'll see.

Thanks
Ben

[mike bryan]

you'll need to consult a manual or talk to a good honda tech on this but there is usually a bolt or nut somewhere around the base of the cylinder you can loosen to see if oil is feeding the top end.while running it should push oil out under some pressure.

[GP-1]

Those old 4-stroke Honda singles are nearly bullet-proof. I'd agree on the clutch issue, but it's so simple (and cheap) to just replace the plates that I'd probably just do that. As far as the ticking noise goes, unless it's really loud I'd be inclined to believe it might be a loose valve. How many miles are on the motor??

[Xlrator]

Thanks guys. I got the clutch going. All the plates & discs were siezed and I hammered them apart with a mallet. Brushed them on a light wire wheel and mic'd them. Well within spec. with a lot of meat on them. For $14 I can get a new set. Cleaned a lot of sludge out of the case. Maybe one of the oil passages going up to the camshaft is plugged with crud. I'll pull a valve cover off and start it.

[triple dude]

If ya want another project, racerx has been cleaning out his shed.He just sold a 79 RD 400 Daytona Special on ebay(that was in the shed for almost ten years) and somewhere back in there is an old RD 200 twin. When it was retired, it just needed a new fuel petcock. It's just a short hop away from you.

[Xlrator]

Where is he at and what does he want for it and I'll think about it. I have trouble taking too many projects at once. That's a good looking bike. I love the look of these old jap bikes.

My father-inlaw supposedly has a Kawi 900 that he laid down 20 years ago. Scared him and never got on it again. It's been in his garage in Missouri and saving it for me according to her grandparents. I won't hold my breath for that one because it so far and nobody really knows what it is or the shape.

[triple dude]

I'm surprised you don't know racerx?? He lives by 47 and 64 in Maple Park, just north of Elburn. I lived in St. Charles until three years ago.