DHZ DPRO 140 almost stalling when sudden throttle is applied.

[K R U P T A]

so i brought a DHZ DPRO 140 second hand and it hasn't been ridden much and has just sat in the shed for 10 months straight, i started it yesterday and it wouldn't idle and was sputtering alot and when i went to pull back on the throttle it would nearly stall. i pulled the carby apart today and cleaned the jets and adjusted the air/fuel screw, changed the oil and cleaned the spark plug (which was back as all hell) as-well as the idle screw, just wondering what exactly the problem is as it still does it and wont idle unless the idle is screwed more than it should be. thanks in advance.

 

[my67xr]

I'm guessing that the Pilot circuit is still blocked?
When you had the pilot jet out did you clean the holes across it as well as the hole through it ?
Also, at the bottom of the thread's where it screw's into, did you check that thew hole that goes through to the main carby bore is open and clear?
The mixture screw control's how much fuel can go through to the pilot jet.
If there's is any dirt etc blocking that up it will struggle to run

How many turn's out is your mixture screw set at now ?

 

[K R U P T A]

i don't exactly know what the the screw was set at because my automotive teacher did it, he owns and runs a motorbike repairs shop so i guess he did it right. i did unblock every hole. would it be the spark plug? i took it out just then and it's got carbon build up around the tip again.

 

[my67xr]

Did you blow the carby out well after cleaning it out, including blowing compressed air through the small hole's on the air filter side?
Was the mixture screw out when you cleaned it too ?
If he set adjusted the mixture screw, did he have the bike there to tune it ?
Usually they are set around 1.5 to 2 turn's out as standard then you adjust it to suit your bike with it running and warmed up.

If the plug was black/sooty then it sound's too rich.
It might need the float level to be set correctly ?
Might be too high ?

 

[K R U P T A]

the stalling thing only seems to happen while im riding it now

 

[K R U P T A]

Update, brought a new spark plug, cleaned carby again and now only run on premium unleaded, but its still sputtering and chokes out when sudden rev and when held open for abit.

 

[my67xr]

So what is the mixture screw set at ?
Have you adjusted it to suit your bike ?
Are you getting a decent blue spark at the spark plug when kicking it over ?
Take it out and earth the thread's to the head and kick it over

 

[K R U P T A]

ill check it out it the morning, could it be the ignition cable thing?

 

[my67xr]

Yeah it could be the ignition coil, could be the ignition coil lead, it could be the spark plug cap, it could be the earth for the ignition coil.
Do you have a multimeter ?

 

[K R U P T A]

there's spark, and i dont have a multimeter

 

[my67xr]

What about the carby setting's ?