honda cb125 tdc

[bub2006]

Hi people. Great forum. I joined a while ago but not made a post till now. Was reading the other posts! I own a 1985 Honda CB 125 tdc. How do i check valve clearances? And also my rear shock very soft. Also what mpg should I be getting? Any help greatfully appreciated thanks
Daz

[Teflon-Mike]

MPG should be 'around' 70ish to the gallon.

Its NOT an ecconomy commuter bike, like a Cg125, nor a fuel injected emmissions strangled comsumer applience with fuel injection like modern (and less sophisticated!) CBR125; it's Honda's 1982, four stroke answer to Yamaha's & Kawasaki's RD125LC and Kawasaki's AR125LC; twin cylinders and twin carbs, a red line set at 12,000 rpm, and the same power as the two strokes, it uses similar fuel if used as intended.

Tappets: I could tell you, but get a manual; it explains all, much better, with pictures. You need a 10mm spanner to remove rocker cover; a 9mm spanner to loosen tappet adjuster lock nuts and very small 'square' spanner, or suitably 'fine' and accurate adjustable to hold the tappets themselves, along with a pair of feeler guages qith a 0.05 (five TENTHS of a mm, not half a mm) blade, a steady hand and delicate 'touch.

While you have the rocker cover off, also check and tension the cam-chain tensioner..... using the same tools, and again, instructions in the manual.

If your bike needs a servioce, chances are at over 25 years old for a TDC, it will probably have never had the opil strainer cleaned; my other half has written a how to on how to remove and clean that without removing oil pump as Haynes suggest, if you use the search function! Worth doing THAT and an oil change, as well as tappets & CCT unless you have some strange desire to inspect chewed up cylinder heads, when the oil cant get to the cam bearings.....

Carburettors are cantankerouse; poor mpg, ritch running and general lack of crispness, often down to badly adjusted choke mechanism, that needs carefully setting up.

Floats also problematic; and often stick, leading to the float bowl over filling, and again, ritch running.

Buy the book, remove spark plugs and use guide in book showing spark plug condition to help you set the carburettors up properly.

Once you have sorted the choke mechanism, and eliminated any problem with the float valves, just a case of getting the thing set up right, and book settings for needle possition and idle jet are as good a place to start as any... be warned; needle has, as most five grooves, but unlike most, where needle is set with circlip in the middle groove, on the CB125TDC it should be in the second from top, one UP from middle..... folk cleaning Super-Dream carbs, and not using THE BOOK... often stick circlips in middle position..... and the bike runs ritch....

Do you think I'm trying to give you a subliminal message here, some-how? Have you worked out what it is yet?

Have you bough THE BOOK yet?
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[bub2006]

Thanks for that I no I need the mañual but havent got it yet. I put btand new filters oil and plugs in. Cleaned carbs out and tightened up the choke mechanism. I used search before but didn't find anythin bout oil strainer. Will have to look agan. I got 160 ish miles from full to reserve which. Think was about 55 to gallon after doing the bits on it so not far off the average. I know it wwas Honda's sporty little bike at the time. I don't ride it hard usually around 6k on rev counter. Thanks
daz

[Teflon-Mike]

you may like to look at these:
Pup-Project: Photo-Resto; Honda CB125TD-C (FINISHED!)
my 1983 cb 125 superdream project
+Corporal Punishment! Foto-Resto ANOTHER '86 Honda CB125T
GET CAMERA START BLOGGING YOURS!
You might find these helpful too-
HOW2: change Oil & CLean strainer (Small Honda's +)
HOW2: Overhaul Clutch (Small Honda's +)
HOW2: Make a Cornflake Paket Gasket!
How2: Fit Head-Race Bearings - Photo-How-To
Might be putting up a top end rebuild one soon.....

Oh & Welcome to the CB125 Preservation Society..... membership's free, but you have to pay your own Shrink bill......
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[bub2006]

Great thanks for that. I do have my own shrink, hired him when i bought my honda vvision! My bike had new gaskets oil seals pistons an rings about 4000 mile ago but it is something I will be checking myself as you never no if was done by previous owner. Will it be ok bein ridden at about 6 k or do they enjoy a good thrashing every so often?thanks
Daz

[Teflon-Mike]

[bub2006]

Thanks for that great to know can give the old girl some welly once in a while. There is a few moped ridind numptys parked up round here but need to give her any stick for them! Any ideas where best place to get rear shock is as mine is very soft and is a sign of it catching the undertray every so often. Is any one on here local to me too? Cheers for help teflon too. Greatly appreciated
Daz

[Teflon-Mike]

That dont sound good...
Dont know where you are, Langly-Mille dont ring any bells, but going by dots on the map, guessing somwehere North Midlands, potteries-ish? (Heads up; TheSmiler, on here bought 'The Corporal' my red TDC off me month back, and he's up in Stoke; may not be far from you if you fancy ride out with fellow super dreamer)

Riding low at the back, I wouldn't imedietly presume the shocks dodo'd. Will be making steering horrible and making entire bike rather 'wooly' in the handling dept though.

PROBLEM is far more likely on 86 Super dream to be a period of neglect and dereliction, siing the rear suspension linkage sieze, followed by being recommissioned and the links freed up by 'bouncing', rust ion the links being dislodged to let it move again, but leaving ruddy great gaps, and excessive wear as rust powder, now moviong between bushes and rollers, acts as grinding paste on the plastic bushes, making gaps EVEN bigger.

Magnified by the shock linkage, makes bike droop significantly at the back....

Shock is a spring, around an oil filled cylinder with plunger in it... apart from the spring loosing tension, tend NOT to change length, and even when they do, not by much....

They DO loose damping effect, and soft spring will make bike a bit squidgy, but if you are riding arse end low, FAR more likely to be the linkage bushes......

Read Snowie's Build-Blog, this is NOT a cice or easy fix, nor is it 'cheap'.....

New pattern shocks are on e-bay, around the £80 mark; nice Hagon replacements are over £250. Second hand shocks, tend to go for around £25/30ish, but as said, likely not to be any better than what you got and unlikely to cure fault.

That will be in the links, where you can bank on at least £90-£100 JUST to replace all the plastic bushes... annoyingly nearly all the joints have TWO bushes on each one, and the 'half' bushes are aprox £8 a price! THEN you have to assess the satate of the rollers inside them, and they can be as much again!

IF you know some-one handy with a lath that has some phosphur bronze stock about, and can grind the old rollers square to get good surface on them, then make phosphur bushed to 'size' of ground down rollers, you might be able to save some pennies AND get very nice firm rear suspension.... but big job.

And not cheap either which way around, I'm afraid. Though difference a decent back end makes to the way the bike handles is amazing!
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[bub2006]

Ok now I'm slightly concerned! The previous owner did strip clean añ paint swingarm but linkage looks in a ssorry state compared to overal condition of bike. I do want to keep the bike and money isn't a.problem. the problem is gettin my bank card from.my other half!
Daz

[bub2006]

Also out of curiousity what Tyre aspect should be on the rear as mine as got a 4.10 18 on it? Thanks
Daz

[Teflon-Mike]

[bub2006]

Could that be a contributing factor to back wheel catching as well? I am ordering the book next week an then start the task of replacing bushes on rear linkage.
Daz

[Teflon-Mike]

[bub2006]

Just checked and rear tyre should be a 3.25. First port oof call will be new back Tyre n go from there. I thought something was amiss when I put a new chain and sprocket on the rear and the Tyre was catching the suspension linkage
Daz

[bub2006]

After some more digging for information the standard Carb jets should be #98. Mine has #140 in. The only non standardpart on mine is a morass 2 into 1 exhaust. I think that's too high a main jet? Am i correct? Thanks
daz

[bub2006]

Damn predictive text should say motad 2 into 1 exhaust

[caravanner]

hi folks I am looking for rockers for the above bike if anyone has any for sale