Bike stall when idling

[Notabiker]

Hi, new to the forum and to biking in general.

Did my cbt a couple of months ago and bought a cheap Sinnis Café 125 from Facebook to get some on road experience.

The bike runs fine, but when idling if I try and quickly open the throttle, the engine stalls.

That isn’t really an issue per se, but the throttle’s also a bit ‘lumpy’ when doing slow manoeuvres. As in the first few degrees of throttle are a bit all-or-nothing.

Thought maybe the carb was a bit clogged, so took that apart and cleaned it but it didn’t seem to need to be honest, and hasn’t changed the symptoms. Also cleaned the foam air filter.

As I said, not a major problem but I would quite like to solve it. More as a learning experience than anything else.

Any help appreciated.

Cheers

[fastbob]

Hi, new to the forum and to biking in general.

Did my cbt a couple of months ago and bought a cheap Sinnis Café 125 from Facebook to get some on road experience.

The bike runs fine, but when idling if I try and quickly open the throttle, the engine stalls.

That isn’t really an issue per se, but the throttle’s also a bit ‘lumpy’ when doing slow manoeuvres. As in the first few degrees of throttle are a bit all-or-nothing.

Thought maybe the carb was a bit clogged, so took that apart and cleaned it but it didn’t seem to need to be honest, and hasn’t changed the symptoms. Also cleaned the foam air filter.

As I said, not a major problem but I would quite like to solve it. More as a learning experience than anything else.

Any help appreciated.

Cheers

 

Did you check the float height ?

[Notabiker]

No. I didn’t realise this was something I could adjust. How would I tell if the height was right?

Cheers

EDIT - I looked up how to do it and adjusted the float to allow more fuel in ( assuming that it would be running lean?) and didn’t seem to make any difference.

[ThePhatomfart]

Dont know this bike but I'm assuming its a Slide Carb and not CV Carb, so is the cable tension OK ,and slide valve working as it should, and what colour is the spark plug (Black , Rich or White ,Lean)

[fastbob]

No. I didn’t realise this was something I could adjust. How would I tell if the height was right?

Cheers

EDIT - I looked up how to do it and adjusted the float to allow more fuel in ( assuming that it would be running lean?) and didn’t seem to make any difference.

 

No , running rich will produce the symptoms you describe so so try it the other way . It's also possible that the float valve isn't properly closing which causes flooding .

[Notabiker]

Dont know this bike but I'm assuming its a Slide Carb and not CV Carb, so is the cable tension OK ,and slide valve working as it should, and what colour is the spark plug (Black , Rich or White ,Lean)

 

Yes it’s a slide carb. It seems to work properly and smoothly.

I’ve only just changed the spark plug, so I don’t think it’s had time to be discoloured (?).

[Notabiker]

 

No , running rich will produce the symptoms you describe so so try it the other way . It's also possible that the float valve isn't properly closing which causes flooding .

 

Altering the float to allow more fuel actually seems to have improved the jerky acceleration. Hasn’t done anything to solve the stall when opening the throttle fully on idle.

So perhaps the issues weren’t related as I thought.

That said, it’s not a major issue I just want to understand the cause.

Thanks for your responses.