Cb125 problems (still) please watch video!!

colourcode · Derestricted Danger Joined: 09 Jun 2012 Karma :

Still not luck new fuel tank new battery and the bastard thing is still revving it's nuts off I'm stumped absolutely stumped please wacyh the below video of me using the choke as if it's a throttle, it will not start without the choke being down

Teflon-Mike · tl;dr Joined: 01 Jun 2010 Karma :

If it needs choke, suggests its needing the mixture richening up. If once started it revs straight up, and doesn't respond to the throttle, but dies if choke switched off; implies that it needs enrichement 'cos its getting air from elsewhere, not through the throttle slide...
Make sense?
Any help?
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colourcode · Derestricted Danger Joined: 09 Jun 2012 Karma :

Will give that a go now is the fuel mixture needle the one on the bottom or side of the carb?

Teflon-Mike · tl;dr Joined: 01 Jun 2010 Karma :

salem1987 · Scooby Slapper Joined: 10 Sep 2013 Karma :

Are the carb slide/slides in the right way?

2 slots on the slide: one long thin one and a small short one opposite.

Short one should sit on the idle speed screw

Edit: should have watched the video first... doesnt sound like slides at all!!

colourcode · Derestricted Danger Joined: 09 Jun 2012 Karma :

simonplatt · Two Stroke Sniffer Joined: 17 Jan 2013 Karma :

the way to check for air leakage is to paint some oil around the manifold joints etc. if its leaking you will see the oil being sucked in.

do not be tempted to over tighten nuts or you will damage.

Bunny Lingus · Traffic Copper Joined: 20 Apr 2014 Karma :

That throttle slide is in the wrong way or I'm an Irishman. Take it out, spin it 180 deg, replace. There is no way its revving like that due to air leaking. Either the slide is in back to front or its sticking on the throttle screw or the throttle cable is not fully entered into the carb top...
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simonplatt · Two Stroke Sniffer Joined: 17 Jan 2013 Karma :

while you were reving it in the video with the choke, was the throttle open or closed?

AzzA1990 · Nova Slayer Joined: 28 Apr 2014 Karma :

As others have said the throttle valve is in backwards i done this a very long time ago when i was a teenager with little knowledge i put the throttle valve in backwards i started the bike and being an automatic moped it dragged me around the car park out the back of my house

colourcode · Derestricted Danger Joined: 09 Jun 2012 Karma :

Which is the throttle valve please folks? The slide connected to the top is in the right way

bypass2 · Spanner Monkey Joined: 12 Sep 2013 Karma :

The throttle cable routed the right way or inner cable frayed. When you put the tank on have you trapped the cable. Throttle cable adjusted to much. Does the twist grip turn freely.

Bunny Lingus · Traffic Copper Joined: 20 Apr 2014 Karma :

Eliminate the throttle slide & the whole cable/carb top/throttle stop screw setting! Do this: Unscrew the carb top. Gently pull the whole assembly out of the carb body. You should have a slide with a needle sticking out of the end, a spring & the cable should run through the carb top, through the spring & engage in the slide. On the slide you will notice that the edge is bevelled & there are two machined slots, a thick one & a thin one. The thin slot engages with a little bump inside the carb body. The thick slot engages with your throttle stop screw which is a fairly large raised screw sometimes with a spring on it. Don't get this screw mixed up with the mixture screw. Unscrew the throttle stop screw, not all the way out, just so it is not impeding the slide. CAREFULLY place the whole assembly into the carb body & gently push it down. Make sure your machined slots are engaged with the throttle stop screw & the little bump. Make sure your needle has entered its hole. Make sure the slide moves up & down freely. Screw your carb top back on. Start your engine. Gently screw in your throttle stop screw until you hear the revs rise a little. Go for a ride & warm up your bike. Tweak your throttle stop screw until your revs are around 1100 rpm. Tell us if this worked.

I reckon either your slide is in the wrong way or sticking in the bore, your cable could be frayed & the inner cable is sticking to the outer or some wag has screwed in your throttle stop screw all the way in to stiff you. If none of this works simply detach the cable from the slide, replace the slide without the cable attached back into the carb, screw on the carb top, start it up...
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colourcode · Derestricted Danger Joined: 09 Jun 2012 Karma :

Guys I think I may have found the problem finally!! The jet that comes up from the float bowl and squirts through the choke is missing a gasket!!!! The petrol is squirting out of the side! How i have never spotted this I will never know !!!

colourcode · Derestricted Danger Joined: 09 Jun 2012 Karma :

Bloody thing won't start now! Anyone know the factory settings for both adjustment screws??

Bunny Lingus · Traffic Copper Joined: 20 Apr 2014 Karma :

You ain't getting no luck with this are you. Start with one & a half turns out on the mixture screw & just loosen off the throttle stop screw. Where abouts in the world are you? Maybe someone can swap your whole carb out?

ed: Sth Wales, too far for me.
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