Rough Idle and Bogging CBF 125 M

[charlieboy1977]

Bought a small project 2011 CBF for my son. Upon collecting and riding back, the engine started to misfire and cut after hard throttles and hills with the engine warning light activated. After a short rest she was off again until the next hill. From cold, it takes 2-3 goes to get started, rough idles thereafter while also having a deep 2 second bog. As mentioned, it's a 2011 and done a solid 20k mileage.

 

I originally put this down to the infamous CBF fuel pump. 

 

I have replaced;

Fuel Pump with another from a breakers (regretting since I'm now doubting the quality)

Plug,

Air filter,

Drained the tank since the fuel cap drain was blocked and water had gathered (also ran a bit of Wynn's through JIC).

 

Have removed and cleaned:

Fuel line,

Fuel injector,

& IAC valve,

Am also running Redex in the fuel.

 

Throttle cable is sound.

What are the next best logical moves? Replace the IAC valve with new?

 

Wisdom gratefully received!!

[Hairsy]

It would be good to find the error code for the engine warning light. From a quick search, I think you need to put the bike in neutral with the side stand down and the engine management light will do a series of short and long flashes e.g. two longs and one short would be code 21.

 

Once you have the code, that will be be the best way to address the problem.

 

And if the code happens to be 21 then I believe it's oxygen sensor. But I'm sure there's many other codes!

 

Try to resist firing the parts cannon at it - its expensive and demotivating!

[charlieboy1977]

Thanks Hairsy!!

 

Isn't it! Close to stoving the tank in with my face at this point.

 

The warning light is only triggered when engine's hot and throttle pushed when bike hill'd. Am reluctant to take it out to provoke but may have to I guess.

[RideWithStyles]

Id go with hairsys suggestion but if no luck try ignition for these reasons:

 

Primary- Misfires are excess fuel passing through ignited cycle and later in the system.

They can try to come off high idle a bit eagerly and sound alittle bit different but not to cut or bog. The bog is from it trying to come off the high idle too early and the ignition or sensor not completely working with it. Was the plug wet or sotty?

if its a hard cut and very quick from high load then I’d be looking at the ignition. 

[charlieboy1977]

Thanks Styles, all very helpful!

Not many misfires and only when hot and pushing it.

Plug was a little white, suggesting running hot/lean mix, which pushed me down the failing pump or partially blocked fuel line route.