Engine power problem

[otto]

Hi,

I have a 2001 Honda 125 CG, it has been with me one year, and before that was parked outside the previous’ owner house for few years, and he was not using the bike at all.

When I bought it needed some work, general cleaning, replace some serious rusty parts, but the engine, amazingly started almost
immediately.


It passed the MOT with another few changes, and I have been doing some miles since them.


From the beginning I noticed that the bike was not giving all the power (let’ say I am new in the bike world) so it took me a while
to realize that with the stroke on the bike was running much better. I mean with the stroke completely open.

And I have been running the bike like that, stroke open all the time, except when I fire the bike. But couple of times I tried to fix it,
cleaning the carb , cleaning the tank, cleaning air filter, but still doing the same.

Could you tell me what could be the reason for that?

(Some reason I though were adjustment of the carb, timing , spark problem)

Thanks

[EnergyInducti...]

Stroke? You mean choke? =)
____________________
Riding: Yamaha RXS100
Aiming for : RD350 + Test
Dream bike: Suzi RG500 Gamma

[chris-red]

Do you mean CHOKE? a little lever on your handle bars/knob on your carb.


When the choke is on the lever is pulled to you or the nob is pulled out.

The choke cuts of some of the airflow, making it richer, it should be easier to start once the choke is on but once it is warmed up it should run crap with it on.

If once your bike is up to temparature it runs better on the choke it means your mixture is lean which could cause overheating. Has it got a decent air filter? If it has been left it could have rotted and be letting too much air in. If it has you need to adjust the carb settings.
____________________
Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

[otto]

Sorry, yes the Choke

[neil.]

Spark plug?
____________________
CBT February 2008 | A2 June 2008 | Yamaha YBR125 (written off) | Honda CBF125 (current)

[otto]

Thanks for your help.
I will check the air filter again, and the rubber that connects the air filter with the carb, I think is not in good conditions, and as you said some "extra" air could go into the carb making a poorly mixed in the carb.

If not ,I will increase the pass of petrol in the carb .

Thanks for that.

[chris-red]

[EnergyInducti...]

[chris-red]

Eh?

I said it was a good idea
____________________
Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

[Robby]

If a bike is running better on choke, then you have a fuelling problem.

If you think the carb rubber is no good, take it off the bike and inspect it for cracks, tears, or any other holes. If you are at all suspicious, replace it. It only takes a tiny air leak to make a huge difference. Depending on the design it may also a new rubber O-ring where it connects to the head.

While you've got the rubber off, you may as well remove the carburettor. It probably has 3 cables going intoi it - throttle push, throttle pull, and choke. Remove these 3 cables and pop it off the airbox, there should be nothing else holding it in place.

Have a look in the howto guides at the top of the workshop forum to see how to clean a carb, the basics are to remove the float bowl from the bottom and clean it, unscrew the brass jets from above the float bowl and clean them very carefully - they're delicate, and a small scratch that make your bike run poorly. Finally spray lots of carb cleaner over the slide and any internal parts you can see.


You will probably find the most of the inside of the carburettor is coated with crusty yellow-brown varnish. This is restricting the fuel flow in the jets, and ruining the mixture.

Also, fill the tank with fresh fuel - old fuel goes off. Change the oil, and change or clean the air filter. None of this is expensive, and if a bike has been standing it needs doing.

[EnergyInducti...]