Choke Problem

SweetCaliber

Hey All,

Recently got a bike (125cc) got it today and am having problems with the choke.

It starts up fine will just about full choke on but when driving and I turn the choke off it cuts out the second I move the choke lever.

I even tried it when idle and felt the engine was hot and the second I touched the choke lever to turn it off it cud out straight away.

Thing is when I leave it just about full choke open, it runs fine, its not over revving and staying at around 2000 rpm when idle.

The bike got serviced today by a registered dealer before I bought it off the fella.

Just wondering what the problem is?

Thanks all!

bladespin

Blocked jet, dirt in the carb?

Xaime

You can ride with the choke half way on for a bit (not too long though) until the engine is warm and then turn it off. If you are already riding the bike it won't cut out. When I turn off the choke on my bike I don't let it rev down to idle but gfive it gas and set off immediately. Hope this helps

SweetCaliber

bladespin wrote: »

Blocked jet, dirt in the carb?

Could be, was thinking it was something to do with too much air getting in?

Must give the fella a text back, he drove it out to me today no bother, really confused with the problem is.

mobfromcork

What bike is it? YoU might need to adjust the idle control. It's usually down near the carbs on the left. If it is down too low the carbs aren't getting enough to keep the engine tickIng over when idling.

bladespin

SweetCaliber wrote: »

Could be, was thinking it was something to do with too much air getting in?

Must give the fella a text back, he drove it out to me today no bother, really confused with the problem is.

It's possible there's an air leak, is it a new bike, was it sitting up a while?

SweetCaliber

mobfromcork wrote: »

What bike is it? YoU might need to adjust the idle c

I know your going to laugh but a Keeway Speed 125.

I know about the bad reviews but my friend has had one for ages and up to now has never given him trouble.

How do I go about adjusting the idle?

SweetCaliber

bladespin wrote: »

It's possible there's an air leak, is it a new bike, was it sitting up a while?

Nope hes being using it to go from and to work everyday so definitely not been left idle for some time.

Skill Magill

Its the little screw on the carb

mobfromcork

Skill Magill wrote: »

Its the little screw on the carb

Not necessarily that screw. I can't listen to that YouTube video at the moment but I'm pretty sure that's for adjusting the pilot jets on the carb. That would be to change the amount of fuel getting to the carbs at low revs. This may be the problem but first you could try adjusting the idle. When you push/pull the choke lever, follow it down to the carbs and see where it connects down there. There will be another connection down there as well usually leading out to the left side of the bike. If you run the adjuster one way you will increase the idle speed, the other way decreases it. On phone now so hard to post up links.

SweetCaliber

mobfromcork wrote: »

Not necessarily that screw. I can't listen to that YouTube video at the moment but I'm pretty sure that's for adjusting the pilot jets on the carb. That would be to change the amount of fuel getting to the carbs at low revs. This may be the problem but first you could try adjusting the idle. When you push/pull the choke lever, follow it down to the carbs and see where it connects down there. There will be another connection down there as well usually leading out to the left side of the bike. If you run the adjuster one way you will increase the idle speed, the other way decreases it. On phone now so hard to post up links.

Thanks,

But its not just when its idle, even when I bring it for a spin and I turn the choke off, it cuts out.

mobfromcork

http://whytlash.powweb.com/mixscrews/idle%20knob.jpg

Photo of what I'm talking about on that link.

SweetCaliber

mobfromcork wrote: »

http://whytlash.powweb.com/mixscrews/idle%20knob.jpg

Photo of what I'm talking about on that link.

Cant seem to locate it.

Here's the choke control:



Heres the carb:



Heres the fuel switch, I think its in the right position yeah?



And heres another view of the carb from the other side:

Soundman

Considering you say that when the choke is on full, it is only idling at ~2000rpm, I would imagine that the idle is set way too low which is causing it to cut out with no choke.

Skill Magill

Theres a flat head screw on your carb (2nd picture) just above the float tank and below the slider.
Start the bike with the choke on, as the revs increase be ready with your screwdriver to turn that screw so as the revs decrease.

carbs.jpg

mobfromcork

In the user manual found here http://www.keeway.co.nz/Speed%20User%20manual.pdf
They recommend the idle speed be set at around 1400 rpm when the choke is off. As posted above, the adjustment screw is probably set too far out.

Best of luck with it

SweetCaliber

Skill Magill wrote: »

Theres a flat head screw on your carb (2nd picture) just above the float tank and below the slider.
Start the bike with the choke on, as the revs increase be ready with your screwdriver to turn that screw so as the revs decrease.

carbs.jpg

So will i turn the screw in till the revs decrease to 1400 or turn it out?

Skill Magill

First, does turning that screw change the revs at all? Or does petrol start coming out from it.If petrol comes out from it its the wrong screw. If it does change the revs, get it to 1400 when the choke is off.
If petrol came out just tighten it back in again.

SweetCaliber

Skill Magill wrote: »

First, does turning that screw change the revs at all? Or does petrol start coming out from it.If petrol comes out from it its the wrong screw. If it does change the revs, get it to 1400 when the choke is off.
If petrol came out just tighten it back in again.

Not with the bike atm but should I adjust it when the choke is fully open? Adjust it to 1400 and then close the choke?

And I'm guessing I turn the screw clockwise?

CJhaughey

I'd say what has happened is that there is dirt blocking the pilot jet.
The pilot jet controls the fuelling up to 1/4 throttle and the main jet takes over from there.
When the jet is blocked the mixture is too lean and thats why the engine only runs with choke on full.
You need to take the carb off and see if the jets are clear then reassemble.
2nd photo the brass screw in the middle of the carb is the idle screw, this will push the carb slide up and down to control idle.
2nd photo the carb drain screw is the one right at the bottom of the float bowl.
This will drain the float bowl of any petrol and dirt/water thats in it.
The little rubber hose that leads from the bottom of the carb is where the petrol will come out of if this is backed out.
1.First off tap the body of the carb with a screwdriver handle to dislodge any dirt that might be sticking.
Then get a clean container to drain the carb into.
Turn off the fuel tap and undo the little screw on the float bowl and catch the fuel in your container.
Check for water/dirt.
Is it clean with no dirt or water in it?
Tighten the screw back up and refill the carb and see if it runs better.
If it doesn't then you need to take the carb off and clean it manually.
When you take the jets out use a brass wire from a wirebrush to clean the jet and remove any blockages.

SweetCaliber

CJhaughey wrote: »

I'd say what has happened is that there is dirt blocking the pilot jet.
The pilot jet controls the fuelling up to 1/4 throttle and the main jet takes over from there.
When the jet is blocked the mixture is too lean and thats why the engine only runs with choke on full.
You need to take the carb off and see if the jets are clear then reassemble.
2nd photo the brass screw in the middle of the carb is the idle screw, this will push the carb slide up and down to control idle.
2nd photo the carb drain screw is the one right at the bottom of the float bowl.
This will drain the float bowl of any petrol and dirt/water thats in it.
The little rubber hose that leads from the bottom of the carb is where the petrol will come out of if this is backed out.
1.First off tap the body of the carb with a screwdriver handle to dislodge any dirt that might be sticking.
Then get a clean container to drain the carb into.
Turn off the fuel tap and undo the little screw on the float bowl and catch the fuel in your container.
Check for water/dirt.
Is it clean with no dirt or water in it?
Tighten the screw back up and refill the carb and see if it runs better.
If it doesn't then you need to take the carb off and clean it manually.
When you take the jets out use a brass wire from a wirebrush to clean the jet and remove any blockages.

Think that might be the problem, she wont start on full choke now either

CJhaughey

SweetCaliber wrote: »

Think that might be the problem, she wont start on full choke now either

Easy to check with a flat head screwdriver and something to catch the petrol.
It would be worthwhile fitting a fuel filter as well.

SweetCaliber

CJhaughey wrote: »

Easy to check with a flat head screwdriver and something to catch the petrol.
It would be worthwhile fitting a fuel filter as well.

Drained the fuel out of the carb still no joy just wont start, its like the petrol isnt getting to the engine, when we kickstart it, it starts for a sec and cuts out

CJhaughey

SweetCaliber wrote: »

Drained the fuel out of the carb still no joy just wont start, its like the petrol isnt getting to the engine, when we kickstart it, it starts for a sec and cuts out

Pull the carb and clean it out.

bladespin

bladespin wrote: »

Blocked jet, dirt in the carb?

Cough, :P

SweetCaliber

bladespin wrote: »

Cough, :P

She seems to be working now Empied the fuel out of it, I'd say it was dirty, put new fuel into her, got her to run and shes starting not a bother now choke is working again aswell, id say the old petrol was in it a while, probably destroyed the carb, but the new petrol seemed to have cleaned it out

Hopefully she will be grand now, shes been running fine for a couple of hours now, even starting her in the cold, perfect.