CG125 bogging, spluttering and popping when cold.

[Rurtbeynolds]

Right, I'm new here so forgive me if I do something noobish

I've got a 1985 CG125BR, bought it around 2 months ago as my first bike. (In retrospect, I should have looked around more but hey)

Recently I've had a different problem with it on a weekly basis. Brake shoes needed replacing, electrics are totally bodged, air filter is a cheap aftermarket cone filter, headlamp is too big so I can't raise the beam making it useless on dark roads etc

The most recent issue is every time I use it for the first 5 minutes it has a hard time getting to 25-30 mph without bogging/spluttering/popping.
I have to just keep driving steadily and gradually build up speed until it sorts itself out.
Does anyone know what's most likely happening?
I gave it an oil change last week (it was doing this before the oil change)
It's pretty much been raining constantly here in Falmouth over Christmas and I have it outside under a sheet at night.
If anyone could let me know what they think I'd super appreciate it!
Thought it could be the air filter but I just don't know...

[Lord Percy]

Do you give the engine chance to warm up before riding it?

[Rurtbeynolds]

I have been recently, yeah. Doesn't make a difference. Still have to go through the bogging stage until it's okay...

[Mark65]

HT leads and suppressor cap all sealed?, fuel mixture correct?,choke working properly?, you can pick up headlights of ebay I think or wemoto, try those first, my CG popped a bit but I tweaked the idle mixture screw and it stopped. Oh and hows the spark plug?
Mark
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07 Yamaha YBR125, 07 Honda CG125 , 15 CBR300R (Chocolate Crank, Deaded), 16 CB500FA, 19 Honda Forza 300, 70 Suzuki SV650

[Rogerborg]

What state is the choke in while you're going through this ordeal? On my CG125-copyengine, I only needed full choke to get it started in the coldest of weather, and was off the choke within a minute.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[mudcow007]

is it on choke when its running crap?

my old CG didnt like choke at all?

[Rurtbeynolds]

Thanks for all the replies.

I had a look at the spark plug this morning and it was oily and black causing a short which stopped the bike from starting. Gave it a clean with a toothbrush and some brake cleaner and hazzah. Works.
But yeah, the oil mix might be a bit funny. Have checked the oil a few times since changing it and it's right in the middle soo...

As for the HT leads and suppressor, I can't say what condition they're in at the moment because I'm not sure what they are...

I was on a ride this afternoon in the rain, took the dual carriageway to get home quicker and my bloody engine died at 50 mph. Luckily there was a lay by close to me. Tried getting it started again, nope. Looked at the choke and it had turned itself on. Took it off and it started up, went down the road a ways and it did it again so I had to find a cable tie on my bike and strap the choke lever down to stop it from dying. This whole time the bike is making pops and bangs.

Sorry for the life story, what a ball ache though.

Thanks for the tip, mark. I'll check the site out.

[Mark65]

Plug sounds like rich mixture, if its dying in the rain it may be the cap mine was doing it got a new one from brooks barn for about £3 and its fine now, the rubber bits must have worn over the years, mine sounded like it was running out of fuel sputtering then died and would then restart straight away.

https://www.brooksbarn.co.uk/NGK-PLUG-CAP-LB05F-R-EACH_A18KI5.aspx

The rich running may be your problem when cold so try a plug chop to see what its like at normal speed if its ok then your idle mixture may need changing. Let me know if you need any thing from a haynes manual I can photo copy it for you.
Mark
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07 Yamaha YBR125, 07 Honda CG125 , 15 CBR300R (Chocolate Crank, Deaded), 16 CB500FA, 19 Honda Forza 300, 70 Suzuki SV650

[kramdra]

HT lead is the thing connecting sparkplug to the coil.


Check your fuel to be sure no water/rust in it, my chinky bike has similar issues with wet weather and does not run well from cold.

Sell bike asap and get one that works is not a CG

[Rurtbeynolds]

Right well I changed the spark plug. It made the bike run a little smoother but still misfiring.
I noticed there was a pretty big leak around the gasket joint so I removed the muffler and cleaned it all up. Rejoined it and covered the link in Gun Gum to help seal any other smaller leaks. Doesn't look pretty but it'll do the job.

I was wondering if the leak in the exhaust could cause misfiring?
I had a look at the coil and couldn't see any signs of moisture or dirt.

Mark, what did you mean by a plug chop?

[mudcow007]