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Bike stall when idling

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Notabiker
Posts: 4
Joined: Sat Nov 02, 2019 4:08 pm

Bike stall when idling

Post by Notabiker » Sat Nov 02, 2019 6:09 pm

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
Posts: 5657
Joined: Sat Sep 03, 2016 1:42 pm
Gender: Male
Bike(s): Harley Davidson 1200 Roadster and er5
Location: Coventry
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Re: Bike stall when idling

Post by fastbob » Sun Nov 03, 2019 1:00 pm

Notabiker wrote:
Sat Nov 02, 2019 6:09 pm
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
Posts: 4
Joined: Sat Nov 02, 2019 4:08 pm

Re: Bike stall when idling

Post by Notabiker » Sun Nov 03, 2019 3:07 pm

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.

MrPickwick
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Re: Bike stall when idling

Post by MrPickwick » Sun Nov 03, 2019 7:46 pm

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
Posts: 5657
Joined: Sat Sep 03, 2016 1:42 pm
Gender: Male
Bike(s): Harley Davidson 1200 Roadster and er5
Location: Coventry
Has liked: 2962 times
Been liked: 2690 times

Re: Bike stall when idling

Post by fastbob » Sun Nov 03, 2019 9:23 pm

Notabiker wrote:
Sun Nov 03, 2019 3:07 pm
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
Posts: 4
Joined: Sat Nov 02, 2019 4:08 pm

Re: Bike stall when idling

Post by Notabiker » Thu Nov 07, 2019 9:12 pm

MrPickwick wrote:
Sun Nov 03, 2019 7:46 pm
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
Posts: 4
Joined: Sat Nov 02, 2019 4:08 pm

Re: Bike stall when idling

Post by Notabiker » Thu Nov 07, 2019 9:19 pm

fastbob wrote:
Sun Nov 03, 2019 9:23 pm
Notabiker wrote:
Sun Nov 03, 2019 3:07 pm
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.

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