KTM 640 carb model - cut out when opening throttle - Please help.

[Goggakop]

Hey Wild Dogs
Please help!
This is weird my 2002 KTM 640 carb model will start fine but cut out as soon as I open the throttle, if I open the choke and open the throttle it will pick up rev's fine but have no power when attempting to ride it!

Offered it to a buddy for the Buff and have to fix it today! 

[witblitz]

Is the bike in nuetral when you open the throttle or is when you trying to pull away that it cuts out?

If it cuts out when you try and ride it, it could be your side stand switch. Follow the side stand switch wires. They will get to a joint (lugs), pull the lugs apart and short them.

[Goggakop]

Thanks witblitz.

Have checked that already.For sure not the side stand switch.
 It will idle happily but cut out when the throttle is opened. if I open the choke it will idle and pick up revs happily when opening the throttle. it have no power when riding it.

[Beebop]

Sounds like fuel starvation..

[Dux]

I am going to be on the road for a short while , call me at about 14H00 - 073 232 5389

[Goggakop]

Will do - thanks.

[ktmmer]

main jet is blocked

[Goggakop]

Found the problem!

It was a hairline crack on the rubber hose connecting the carb to the barrel!

Thanks to all for the help!

[Goggakop]

Found the problem!

It was a hairline crack on the rubber hose connecting the carb to the barrel!

Thanks to all for the help!

Not completely true - the carb needle was broken! Yes in two sections! Right below the c Clip!

[sventer]

I happened to develop the same problem in April this year. This was on my way to Mosselbay. The needle broke off and got stuck. The end result was a snapped chain and front sprocket damaged. Not nice!

[Beebop]

I happened to develop the same problem in April this year. This was on my way to Mosselbay. The needle broke off and got stuck. The end result was a snapped chain and front sprocket damaged. Not nice!

OK I'll bite.....how ??