And to add to what Stromer said, members here have mentioned getting bits from ebay and found poor tolerance control. I picked my bits up from a local hobby store and they were pretty spot on.

 

Got the bits in a set from Amazon. I did measure it, was a hair over 0.5mm. I don't recall putting a crazy amount of pressure on the bit, but it definitely did not go in easy. Maybe i got a set of rejects or something?

I'll see about getting some quality bits from a hobby store like Lee Valley. Last time i checked, I did not see a drill bit under 0.021" though.

 

Yeah, the drill bit should have gone through that brass jet like butter. What I might guess happened is that it went through the hole so quickly and easily that you pushed a hair too far and hit the casting in the carb. The distance from the jet to the casting is fairly close from what I recall.

 

 

Just think, once you've solved this problem, you can drill your Pilot Jet, Main Jet, Slide lift port, the Air Jets, and whatever else you can find to poke a bit into...

Or perhaps the owners of such threads should remove all references to drilling anything on the CVK in order to prevent this needless crap...

While drilling the starter jet will allow more fuel into the system only when the choke is pulled on, relief can also be found with a proper Pilot Jet (#38 or #40) and then, "instant starting" is available by simply pulling off of the KACR spring..

 

Rotten luck on the drill bit, hope the new carb works out. If all else failed perhaps you could have disabled/plugged off the fuel enricher circuit and installed a slightly rich/richer pilot jet for the cold weather starting.

 

Maybe just forget about doing anything with the bikes. Never crack anything open and you won't break or foul up anything. That is another solution. Leave them stock and buy a bigger bike when more power is wanted.

Just because some people cannot do a job or do not like a good modification is not a reason for everyone to disregard the modification. It just means some should not do the task, leave it to someone else, or learn the hard way. I'm betting a lot of top notch builders and tuners screwed up their share of parts. A lot of top notch builders also may not use the same modifications either. Maybe they should have quit too?

I, myself, do not think so. Mistakes and failures are part of the learning process. Plus there is often more than one way to achieve a goal. It is the spirit of hot rodding at its core.

 

After you get your drill bit out, there is a fix for this instead of buying another CVK carb or messing with trying to remove the pressed in starter jet.

I drilled my starter jet way too large. I couldn't afford another carb and didn't want to try to remove that pressed in starter jet, so I tapped the base of the starter jet with a 3-56 tap, then tapped a piece of scrap iron to use as a die to create a jet. I put a piece of 3/32 brass rod about 4" long in a drill and used a file to thin out one end. When it was the right size, I bent a 90 degree handle on the fat end and threaded the rod on the thinned end with my homemade die. The piece of scrap iron made a great jet holder while I drilled the jet and slotted it for a screwdriver blade.

The first jet I made was too large. I bought a .5mm bit set from the cheap tools place in town, made that jet and installed it. The choke would work, but it was way rich and would die in less than a minute. I bought an .18 thousandths bit from a hobby supplier on eBay and mic'd it BEFORE I drilled my latest jet. Lesson learned.

Just finished removing the large .5mm starter jet and installing the homemade .18 thousandths jet in the carb today. The bike fired right up and went to 3K rpms, continued to run and gain rpms slowly until it was warm enough I took it off choke. The jet is installed on the bottom end of the starter jet housing and about 2mm long. It is almost flush with the bottom.

Necessity is the mother of invention.

 

Its .018 correct? Not .18"

Sorry it was just bugging me.

 

Yes, .018. Sorry about that. Bike still cold starts fine.