Carbie troubles!!!!!! HELP

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Dec 27, 2005
I was looking at the intake on my carbie (the threaded part and noticed the 3 holes along the intake, i looked on the other one and the 3rd hole is blanked out , i looked at some other carbies i have lying around and noticed they are all the same with the blanked out bit. could the carbie with all 3 holes open be causing that side of the motor to run rich??? as when i give the bike throttle and at idle it blows black/grey smoke (petrol smoke) could that hole be causing this richness.

Also i cant seem to get the other carbie with the hole blanked to run at idle and no matter how far in or far out i adjust the mixing screw it doesnt affect therefor i have had to tune it to idle on one carbie. any advice would be very helpfull.
Only two holes should be un blocked, I think the third is there to suit which hand the carb is made to, left or Right.

i just put a peice of wire down the hole i thought was open to find it is actually blocked but about halfway down this hole. but this still does not explain why the other carbie wont work at idle.
The carb not working at idle sounds like the classic pilot jet blocked problem. Buried deep inside your carb there is a pilot jet which tends to clog if left for any period with fuel in there. It is very difficult to clean, you may be lucky with carb cleaner and compressed air or an ultrasound cleaner but more than likely you will need to drill opposite the air screw and poke it out (carefully) this site explains all
thanks for that great website and i might just do that fix with the blanking screw as i have acces to a engineering workshop at school.
What a great site as i've said before 'ain't the net great', with sites like this forum and that magical site about carbies. In the past if i've had any concerns about the pilot airways being blocked i just blow down either the adjustment screw hole or the air intake hole at the front of the carbie and air should come out of the the little hole in the bottom of the venturi area of the carbie, if not you've got a blockage.
A # 78 drill held in a very small brass tube from the hobby shop by a hard squeze or a pin vice built to do this job will clear your jet. Since this will not be the last time get the right tool. The drill is .016 dia. same as the jet. Just remove the air screw slowly twist to remove the gunk and crystelene you will feel the the hole with the drill be gentle don't press hard just spin. Now use brake clean with the little red tube to wash the rest out the hole were the belmouth is your done re-set your idle air screw.
i did the little trick with adding the screw on the other side to a spare carbie body and it makes it easy to see the brass fiting and small jet wich i have discovered is blocked, and now have the carbie socking in carbo clean to clean the carbie and help dislodge wat ever is stuck in there.
Jet cleaning kit...

If you know someone that plays the guitar and they are about to replace the steel strings.....ask for the pieces they will have to clip off anyway when finished. They are a nice assortment of thicknesses, and might just be the trick to get a jet unclogged...and cost nothing.... :D
Well i have got the idel jets cleaned and now the bike is going better then ever, the guitar strings did the trick and so did the blanking screw mod wich allowed me to see right through the jet. so a big thanks to everyone who gave me advice.

Thanks Julian.
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