Pilot jet cleaning

I know the information is on here somewhere, but I just couldn't find it with search function.
In trying to diagnose the poor idling of my Atlas w concentrics and a magneto, I have not yet looked at the pilot jets to see if they are clogged, and the guy who does work on the bike told me that I should use a 17 thousandths inch drill bit to clean out the passage.
Problem I have is that no regular hardware store carries such a small bit. A machine shop guy said I might want to use acetylene torch tip cleaners and i bought a package. The tip cleaners come in a package w sizes ranging from a #6 to a #26.
Anybody have any idea what size is closest to what I need for th job

We see No # 78 drill size mentioned regularly. (Or is it # 74)
Piano wire also gets mentioned.
In desperation, I've also used a stray wire from a wire brush, that had been shedding loose wires.
Fairly fine diam - not all are.

I thought acetylene tip cleaners had like a coarse file finish effect to them, to bore out the rubbish in the tip.
Not what you want in jet cleaning, the idea is to keep the hole size intact. ?
The holes are pretty fine too, tiny...

Thanks Rohan.
Agree that the tip cleaners are more abrasive and all we're looking at doing here is cleaning and not reaming.

Does this link work?
http://www.ebay.co.uk/itm/10-Piece-...340?pt=LH_DefaultDomain_0&hash=item27b334feec

Otherwise, use a piece of 16 gauge guitar string. If you know anyone who plays a guitar, I'm sure they'll snip a couple of inches off a new string.

Actually lucked out after checking in about 10 different places- found a set of bits from 61 to 80 at an Ace hardware store. Now it's out to the garage to make a little holder for te bit, then clean out the pilots. We'll see if that helps the idling problem...

Pilot jet cleaning relatively easy once I secured the #78 bit to a WD-40 spray tube. FWIW, the superglue did not work. I melted the plastic around the bit and it worked well.
Anyhow, took the Atlas for a ride and everything seemed to be in place- it started after 2 kick-throughs and a kick, and idled nicely. After about 20 miutes of around-town riding, it died again as I was downshifting and slowing for a stoplight.
It fired again with a quick kick, but I had to keep blipping the throttle to keep the motor from stalling. Finally it just flat out stalled, and I must have kicked it 25 times before it fired back up. Rode abut 1/2 mid, did again. Again, multiple kicks, fires up, dies 5 minutes later. Once dead, no amount of kicking wakes it up until after about 10 minutes, when kicking brings it slowly back to life.
I know this isn't right, and I'm trying to think of next steps. It runs well initially, but once ht, can not be depended on to continue running, or counted on to start back up after stalling.
I am very comfortable with kicking Nortons over, so I don't think it's technique. Something else is going on here.

Maybe it could even be that your magneto is getting hot, and pumping out weak spark?
Why don't you carry a spark plug with the ground electrode bent out so the gap is about 3 to 5 mm and when it stops next time, plug it in and hold it against the head and kick it and see if the spark jumps the gap?
Just to rule out this as a cause before you go on

I kept losing the tiny #78 bits and also they are not long enough to reach. I JB Weld them into a air needle used for filling up basketballs or soccer balls. Makes a great handle and they are easier to find in the drawer. They work much better than a guitar string too.

Good tip for the air needle holder. Losing them? Mine came in a clear plastic cylinder. An old film canister would be just as good.