Warm Idle Issue / 3/4 throttle bogging

[blokeonspokes]

Hi all, first post.

Bought myself a Honda CG125 K-reg, 32,000 miles.

While I paid £400 for it, it's been royally punished over it's years of ownership from whoever had it beforehand.

The previous owner seemed experienced in his bikes, but he sold me a deathtrap, a shame, the Honda was in no fit position for me, but I persisted and managed to do a lot of work with the piston, 6V Loom, tightened tappets, fresh oil, new (correct) sparkplug, bits and bobs all over and new tyres.

I've done a lot of maintenance on it over the 2 weeks of owning it all the ticks, dings and pops have been sorted and I've restored the majority of the bike to it's former glory (what glory it had in the first place), but there's two little issues I just can't get to the bottom of.

Bogging when throttle is 3/4 applied, bike 'judders' at this point.
Also, the bike runs fine for 10 minutes from first start, then dies out during idle when warm. This has only started since I've placed on a new, Chinese carburetor. I am going to replace the old one if I cannot fix this issue.

The person who I work on my bike with, swears down that the carburetor I have put on is fully open when the choke lever is 'up' - the bike revs it's nuts off when choke lever is half-down/down.

The idle screw has been adjusted to allow tickover, but this just makes the initial warming-up of the engine rev sky-high, then once warm, it, once again dies on idle.

Another note, the carburetor makes a sharp 'PSST' noise when the bike cuts out.

Any advice would be massively appreciated.

Anyone calling me a soft-serve fecal whippy ice cream will also be agreed with, it was my mistake buying this bike, so I shall rectify it by fixing it. I do not care about the 'more money than it's worth' statement.
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Pass me that one, you know, the thingy, the spanner-thing.

[Easy-X]

Assuming you're restoring it and not dicking with it (e.g. cone filters, yay!) then I'd look at your air intake for leaks.

Also, you say you have a carb cast in that rare Chinesium metal but have you done anything with the jetting since you got it or just plonked it in?

Nice avatar, BTW
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[jaffa90]

Give it some fuel providing the exhaust system is clear.

[blokeonspokes]

[blokeonspokes]

Going to return the old Jap carb on it from Stock, clean it out etc. These shoddy £12 carbs aren't suitable as replacements unfortunately. Turned the idle screw by a fraction and now the bike bogs heavily at high-rpm and won't idle without bogging out or racing high stacking rpms.
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Pass me that one, you know, the thingy, the spanner-thing.

[jaffa90]

""""Would the exhaust being clear mean no shims?""""
I mean nothing collapse inside.

[Robby]

Get a Haynes manual.

Make sure the original carb is properly set up according to the Haynes, and clean inside and out. This is a lot easier to do with the carb on a bench, so do it all before fitting back in the bike. Pay close attention to float height and mixture screw setting.

When you refit it, make sure it is well sealed at both ends. The rubber boots that it slips into will be hard and want to fold over. A bit of lube helps.

Don't chase any problems until you have the carb sorted. It all sounds like fuelling, and you fitted a shit carb.

[blokeonspokes]

[blokeonspokes]

Hi Gents, finally made her idle - bogging still occurs but now about 4/5ths of the way so not as bad. Only issue now, she's idling slightly fast - Am I running too lean?
____________________
Pass me that one, you know, the thingy, the spanner-thing.

[jaffa90]

Sounds like it`s getting a bit more fuel with this carb,

You may have to put a denser air filter in or lift the main jet needle one notch.
If you increase or decrease the pilot feed fuel you should be able to drop the idle speed with idle screw.

[Easy-X]

There are numerous articles on the InterWebs about how carbs work and how to tune them. I suggest a little study

Basically: idle to ~20% - dick about with the idle and mixture screws.
20 ~ 80% - dick about with the needle height.
Full throttle - dick around swapping out the main jet and swearing a lot.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[blokeonspokes]