High-quality Honda CG 125 carb rebuild kits

[wulfprints15]

Hi guys, first post here.

Just bought my second bike, a 1996 Honda CG 125. It was refurbished about a year ago but not ridden much at all after that. From what seller said seems like less than half a dozen times in the past year or two.

It has issues when trying to run at high-revs. For instance, on the ride home, it would be fine one second but then suddenly start cutting out when I twisted the throttle any further than 1/4 to 1/2 ish (varied a bit each time). I don't mean stalling because the engine didn't necessarily stop running, it just started making a deeper exhaust tone and stopped producing power. I was struggling to maintain 25 mph on a relatively shallow incline at one point.

Strangely it starts up first time almost every time when cold BUT if it does stall after the above-mentioned symptoms it becomes absolutely impossible to start.

I believe this could be due to a couple of things:

The spark plug doesn't look all too shiny, so I'll be replacing that.

Noticed the battery terminals could use a bit of TLC.

Since it's sat for so long I reckon the carb could also use a bit of TLC.

That last point is where I'm having issues. I can't find a genuine (or even high-quality aftermarket) carburettor rebuild kit (new jets and gaskets etc) anywhere online. Does anybody know the best place to look for this in the UK?

It's, as far as I can tell, a genuine original carburettor. It says Keihin on the side, but that's all the markings I can see without starting to pull bits off the bike.

Cheers,

Jamie

[Easy-X]

Wow, just searched for CG125 carbs and chinese copies go for a tenner these days

Definitely sounds like it's worth focusing on the carb but you also might want to check the air intake and filter - just to tick off the list.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[bladerunner]

I would strip the carb and check for gunk or tarnish from old fuel before jumping in with an OEM rebuild kit. Sounds like the idle circuit is good so emulsion tube,needle setting and air corrector settings would be my first port of call. Main jet will get a clean as you check the needle jet/emulsion tube etc. these things are as simple as carbs get. As a sanity check do make sure you have a good flow of fuel coming from the tap in both on and res positions as no amount of carb faff will fix a fuel supply issue, a blocked tank cap breather can cause all sorts of similar symptoms.
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Current bikes...cbr929, KDX200's, Rd125lc mk2, RGV250's

[Teflon-Mike]

There are hundreds of CG carb kits and CG copy carb kits on offer, esp on the bay... high-quality? that's probably the issue.. b~u~t.. start at the top.

Symptoms described don't necessarily sound like a worn out carb is 100% to blame. Start at the top, ans work down systematically and methodically.

First up, try a compression test, or just rip the top off and have a look at the bore and rings. Symptoms to my mind suggests it's not taking load and good odds that's knackered rings or bore, and low compression.

Dereclicts left laid up suffer this badly, 'cos iron piston rings in an alloy piston in a steel barrel corrode electrolytically due to the different electro-potentials of the metals, which results in the rings sticking in the piston grooves and not giving a great seal... any wear in there makes matters worse.

Personally, rather than fretting about carb-kits, I would start with a chinky barrel kit; last time I looked these were only about £30 for a CG, so I'd cut to the chase on tyhat one and tear the motor down, get rid of old bore, piston and rings and know that be good. Its 'cheap' and cheaper than a re-bore and new piston.. so what the heck.

Whilst the head off, I'd look carefully at the cylinder head. Good chance that valves and seats are pitted and corroded. In fact, good odds that on a CG the valve clerances have never been properly adjusted, and more that the rockers and or tappets peened and bantered... more stull that bad adjustment, probably wothouty the propper tappet key has chewed them even more....

On that notion, for the small cost, I'd get the proper tappet tools, (Part no's are in one of my how2's somewhere in profile), and a new pair of virgin tappets to replace any carnage in there, than I would with the head off, pop the valves, clean them up, clean up the seats, then properly lap them back in with grinding past. Eliminate that variable. OTMH the CG has no valve stem seals, or just one; if it has any, I'd swap them out whilst valves out.

Then I;d slap it all back together again, with the new barel kit, and be damned.... should be known good and eliminate so many possibilities at source. And the little CG motor is so crudimentary and easy to work on, it would probably take me less time than properly overhuuing a carb!

So, engine 'reconditioned' and back in the frame; I'd look at the rest of it.

A loot of assumed carb faults arent, they are buggered exhausts. ~I'd check that next, and again, for the cost of after-market CG copy pipe, probably just replace.

THEN I might look at the carb.... Going by date, I have an incling that it could be either the plain ca4rb, or the pumper. The pumper has a small plunger set up on the slide so that when the throttle was opened more quickly, it squirted neat fuel into the engine, to compemsate for incredibly lean jetting. Pumper carbs have a little piston and diagphram arrangement to do the pumping, and that diagphram can perish with age or modern ethanol fuels.... If a pumper, I';d be more worried by that than a rebuild kit, and probably looking to chunk it in favour of a plain slide carb, especially if planing to run regularly on modern Ethanol fuels.

But.. carbs, are not the mystical bit of kit they are often imagined, they are just a collection of tubes, and pretty innert, and dont readily wear out.

CG's Keihin PD is also pretty robust and designed for farm-yard fiddling. Float bowl for instance has a rubber gasket that's re-useable... you should be able to strip it, soak the jets and clean the needle and put it back together no parts required. E-Fuel issues excepted... but there's only really the main float bowl gasket to worry about, and if shot, or peeing petrol, I;d just make a cardboard one from an old corn flake packet.

More worrisome, is the pilot air screw, which has very fine tapered needle on the end prone to sorroding in the carb body. Also has an O-Ring and speing under it. Here one of the cheap e-bay kits can be a boon, and provide a new air-screw, O-ring and speing, for less cost than the separate piece parts... after spending a bit of rime with an old freyed clutch cable poling out the old needle from its hole during cleaning!

B~U~T.. there you go... getting brave and diging into the oily bits, these angines can be made good for reletive pennies and a lot less hassle than trying to tinker with the bits on the outside and not see oil.

Patience and diligence are required, not necessarily many new 'bits'.. but your bike, your problem, your call.... B~U~T I would NOT be so worried about the availability of a dedicated 'Cab-Kit' and starting elsewhere.... an cutting to the chase, looking at oily bits.
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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?'

[stinkwheel]

Allens performance for genuine carb parts. If they don't stock a specific kit for your model, they'll have the bits. Best bet is to call/email them with the carb part number (should be stamped on it somewhere).

https://www.allensperformance.co.uk
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[MarJay]

Start with the cheap stuff first, like plugs electricals etc. Then later move on to expensive carb parts.

Or try Chinese and see if there is an improvement, and if it's not perfect go to Allens. I reckon a kit will be a surprisingly high amount of money for a bike that isn't worth all that much.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[wulfprints15]

[wulfprints15]

[wulfprints15]

[wulfprints15]

[Teflon-Mike]