cg125 engine kicking

[Retro-Man]

Hi All
First post so please bear with me.
I have a 1999 cg125 which is my first ever bike. the engine starts and runs at idle fine how ever there appears to be two issues
1. It will not run (hot or cold) without choke,although it does run fine with partial choke. but more concerning is that at the top end of the rev range in any gear but more noticeable in top the whole bike seems to lurch forward/holdback repeatedly. this is alleviated by backing off the throttle slightly. I have three theories of my own but am looking for some more experienced opinions.
1. this is normal operation of cdi rev limiter
2. there is a carb/fuel issue
3. (not likely) but it has been hinted at that my chain may have stiff links

I am loathed through my lack of experience to remove /strip carb
but I did put some fuel system cleaner in the tank this morning which seemed to make a small difference

any tips for a newbie appreciated

[alains]

my diag is that you run with a poor mixture
1) clean your tape & then CARB (humidity & bad petrol add water inside)
2) blow every jet inside (if you've no air pressure buy a spray)
3) clean your air filter
4) refit everything (if you can , put some petrol in the carb avoiding pulling long time on the starter)
5) control or change you sparkplug
6) adjust the throttle stop screw a bit higher than previously . start engine (choke on) let it warm 2 mn. then adjust the pilot screw (i do not know how many turns , but look on your book)
7) now take choke off , move the throttlle screw to go at 1500rpm and bit by bit do or undo the pilot screw until you find the better running . if nothing change set it as original
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[Retro-Man]

Thanks for the detailed advice I will try this over the weekend and let you know
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[dibbster]

Its definately not 1, I would think 2 would be your most likely problem.
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[stinkwheel]

Keep it outside? Been riding a lot through the week?

You could have water in the petrol which classically causes 'kangarooing' and general shitty running. Simplest cure is to put an anti-water fuel additive in the tank. CGs used to have a sediment bowl on the fuel tap, if yours does, carefully unscrew it (without spilling the contents) and have a look inside. If there is water in there you will be able to see it as small (or one big) droplets under the petrol.

I'd make sure the air filter is clean too, and that the breather in the petrol tank cap is unobstructed (blow through or try running with the cap open and see if the problem goes away) before I started buggering about with the carb.
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I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[ts50x0]

my cg did that and when i cleaned the card out it was still doing it. i cured it by adjusting the valve clearances.

[Retro-Man]

cheers to everybody for the advice
one thing seems to settled (its not normal)
the general opinion seems to be a fuel issue. all I have to do now is find the time to fix it
LOL

cheers everybody
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[Retro-Man]

had time today to remove carb (dont know what I was worried about ) quite a simple strip down, clean, blow out jets and reassemble. fitted carb back to bike and tested guess what bike runs sweet.

cheers to all for the advice
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