Carb Adjustment, Honda CG125 2007

Hi folks.

My CG125 runs ok but I'm pretty sure it's running too rich and I want to sort out a few niggles.

Example, when I fully open the throttle quickly (either hot or cold bike), it starts to stall. I'm guessing due to too much fuel in the mix?

Also, it backfires and sometimes misfires (hot or cold), I think this again may be due to too much fuel in the mix.

The bike is regularly serviced with new oil and plug, but It does however need a fuller service as its done 7k now and I've had it from new.

By the way, It's always been like this from day one, so I'm guessing I need to adjust the carb fuel/air mixture to run leaner...

What screw do I adjust on the carb to do this? I know which one is for idle speed.

Regards

Dont you have to take the carb's apart, and adust the fuel needle, moving it upwards a few clicks for a less fuel, hence a leaner mix?

Dont take my word for it, am well off anyone who has limited bike knowledge...

Ah CG125......i remember when i had one....last year :P

Yep you'll need to take the carb off ideally. If you want to have less fuel going into the motor then you want to drop the needle. The only way you'll know for sure if its better is to try it out. I found with my cg125 (well it was a cg 125 motor in a chinese bike) that you could do away with the air box and put a simple air filter on to sharpen things up, i used a K&N i had lying around. If you're ognna do a service then make sure you check the valve clearances, believe me, even the smallest adjustment will make a feel-able difference. Oh yea, give the carb a clean when you have it off, its worth it. Enjoy...

[maviczap]

On my old CG there was a pilot jet or similar which you could adjust without having to take the carb off!
This adjustment was underneath the front part of the carb, just where it connects to the inlet stub. Most people don't know it's there.
The needdle is on a screw thread and there should be a tiny spring on the inside to stop the needle vibrating out.

From memory the needle needed to be turned out from fully closed about 1 1/4 turns. If there is no needle because its vibratred out (mine had) then the bike with run very roughly.

Not sure if this is on the newer CG's but they probably haven't changed that much, because it's such a reliable engine.

I was close? (ish) haha
Sorry for the mis infomation..

[Biker Biggles]

Id pull the plug out first to see if it actually does run too rich.Lean it off too buch and you will burn the piston out.

Good point, white is too lean (close to blowing up )
Black is too rich, looking for a browny colour i think?

[yorkie_chris]

Yes you want a coffee colour.

Simple motor, do some plug chops. But it is slide carb, so if you just whack the throttle open it will bog.

[johnnyrod]

Indeed, nothing you can do about that, except be more gentle with the throttle. As for the backfiring, when does it do this? After you close the throttle/under engine braking? While gassing it? Doubt you need to adjust the needle etc. as this is a small carb you can probably sort most of it with the idle mixture screw. This would be the place to start anyway otherwise you might not be "fixing" the right thing.

Quick one if you have an exposed K&N air filter can you get it wet in the rain???