Honda cg125 wont start

[geohammer]

hello all,

been a lovely few days in UK so took my bike out for a good drive about 5-6 days ago now, was working like a charm up until last part of my journey as it seemed to lose all power at a set of traffic lights but swiftly returned after a pull on the accelerator, got home fine but tried to start the next day and it simply would not start on electric start just makes clicking noises.

the next day i charged the battery up and attempted a bump start, after a lot of running managed to get it to start only for the engine to swiftly die again after letting go of the accelerator.

managed to bump start it again but this time i altered the idle speed screw and managed to get it to idle on a slightly higher rev for a while until it cut out again, tried the electric start, made the same clicking noise for a few seconds and then kicked back in, was thinking great, let it idle for a while and warm up with a few revs then turned off for about 5 minutes, tried the electric start again and back to the original clicking with no attempt at the engine starting.

things i have already tried:

charging battery up multiple times,
cleaning carburettor out,
filling tank,
checking the voltage of the battery,
checking spark plug for spark (sparked fine),


all of this has me very puzzled so any help would be much appreciated

[neptune8]

It seems to me that you may have two separate faults, electric starter not working, and an engine fault. If you hear a click when pressing the starter button, it usually means worn out brushes in the starter motor, or a weak battery. Have you tried connecting the bike battery to a car battery with a set of jump leads? [ do not have car engine running at the time]. If it still just clicks with help from a car battery, likely cause is worn starter brushes. You can buy a starter repair kit, including new starter bearings for under £25. It is unlikely that a weak battery would cause engine running problems, as the ignition system runs direct from the generator on a CG125.
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[geohammer]

[jaffa90]

That clip was the sound of an engine not starting, what is the battery voltage after being off charge for a few hours?
Also did you removed / check the pilot jet in the carb when cleaning it?

[geohammer]

[jaffa90]

I would check the fuel flow to the carb, also the pilot jet works mostly up to 2/3,000rpm. It could be wise to fit an inline fuel filter just in case the tap or tank is passing foreign bodies.

[geohammer]

[jaffa90]

It sits in between the tap and carb.
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[Teflon-Mike]

The e-start is one issue... why wont the engine stay running is another, and the main consideration here; DO NOT let one confuddle t'other.

As for starting; you imply that it was laid up or less used over winter; this kills already tired batteries. A gummed-up lazy starting engine, even more so. Dont go jumping to conclusions over charging systems and wot-not, start at the top.... check battery condition... terminal volts does NOT tell you how good the battery is or what its charge holding capacity may be... they ais cheap... get a new one! Follow the instructions for filling with acid, and trickle charging before use.....

You would probably benefit from pulling the starter motor, and reconditioning with new-bushes etc... but ISTR that 'pattern' replacement e-starts for the CG as used on Chinky copies, derivatives and clones, is bludger all more expensive off e-bay than a pair of brushes from Dave-Silvers....

While starter 'off' check the drive and clutch; clean and grease before refit, then pay attension to the earths.. that start with the metal-to-metal faces of the starter bolting to the crank-case, and probably try and worm thier way home through manky old bolts to the frame, where there aught really be an earth braid from the starter motor mount bolt to the battery-neg..... crack out the emery paper, and wire brush, and look for an old earth strap that's long enough from a car!

NOW... lets look at why this 'ere engine conks out.. WHY oh WHY did you dive into the chuffing carburettor?!?!?!?!? Whgen was the last time this thing had it's tappets properly set?

Sorry, B-U-T, big bug-bear.. carb is on the outside of the engine, obviousely identified and EVERY-ONE says 'clean the carb'..... 'cos its a lot less scary than looking at bits covered in oil!.. well, it seems to be!

Lifting the rocker cover, is no major deal, its designed to be lifted for routine maintenance, around every 2000miles or so... carburettors are NOT expected to need faffing with, for YEARS....

Hint... lift the effing rocker cover!

Do the tappets! Make life easy for yourself, get onbto Dave-00Silvers, order the tappet tool and spanner, and why not push the boat out and buy a pair of brand new tappets....... IF they have ever been looked at then the top ends where monkeys DONT use the propper tappet key have chewed them trying to tickle with a pair of pliers or mole grips.... If they haven't been looked at... then they will likely be mashed t'other end, where they have been hammering the valve stem over the enormouse gap.... for £2 a pop... just buy-em incase!

NOW.. do oil change; and clean or replace the air-filter....

How old is the petrol in the tank? Been sitting there since last autumn? Good chance that the petrol is 'stale', A-N-D the bottom of the tank is full of water that's condensed on the inside of the tank, and then settled.... then with use, been shaken, not stirred like a pretentious martini, back into the fuel, to cause grief as the level drops....

Drain the tank, petrol tap off.. and chuck the old away, or save for cleaning stuff! Dry the tank well in a warm place, then stick in a couple of gallons of BP's finest......

Clean the spark-plug, better still, fit a brand new one......

Look at the Haynes manual for the propper carburettor settings.. put them there!

If you have been monkeying about with the carb... get new gaskets and fit them, so it seals properly.......

Tension the drive-chain; replace brake fluid, adjust brake shoes, check tyre pressures... go down the WHOLE list of routine maintenance, and base-line the thing BEFORE looking for 'problems' less trying to fix stuff that may not need fixing!

Good odds, that the symptoms described were caused by nothing more than old stale petrol and condensation in the tank....... and effing about monkeying with the carb, in the misguided belief that is what you should do, has MADE more problems than you had to start with.

On topic of in-line fuel filters... DONT.

If tank clean, and if new petrol is clean, you dont need one. If not... then an inline filter is not fixing the problem, just masking it.... you need a clean tank and new fuel NOT a filter..... inline filters 'as a precaution' in-my-experience make more problems than they solve, with air-locks and lag in the pipe delaying fuel flow, especially if a Morris-Minor or Mini car sized thing from Halfrauds....

But that's the start... new fuel, flushed tank, and a service, should sort, or at least give base line for further diagnostics on the engine issue....

Starter clicking issue, is a tangential one to that; needs sorting, but, only so you can get the thing to start and sort the engine issues... otherwise they are seperate problems. As said, new battery is a good start, starter-motor overhaul and check on earths, pretty much the sledge-hammer cure-all, and worth the doing regardless.
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[GSTEEL32]

How many miles did you cover in the 5 days it was working.?

It could be fuel starvation.

I'd try cleaning up the fuel tap, any online fuel filter that may be fitted, and run it with the petrol cap off. If it makes no difference, you can discount it.

If the bikes responded to you changing the idle speed, I'd leave the carb well alone for the moment, as it's indicating the jet isn't blocked.

The clicking is definitely a power issue. If you're happy the battery is good, all your connections are good too with no corrosion, would it not be easier to buy a second hand starter unit off eBay?