Pilot Jet

I’m having some trouble with hard starting my 1982 Kz 1100a2. I watched a video on YouTube from Kaplan out in Connecticut on the same bike he was selling and said that the mechanic “best carb guy out there” micro drilled the Pilot Jet. My question to you guys is what size should I Micro drill this Pilot Jet out to? Scirocco from Germany 🇩🇪 you helped me last time with my vacuum Danke Schön. P.S cleaned carbs already ready to remove again 

There is no reason to drill any jets. It's a bodge. Only an ham idiot mechanic drills jets. 
Genuine jets are precision made parts and available in increasing increments. 
If you bike is hard to start in cold weather but runs fine when going the issue is nothing to do with jets. 
Its more likely weak spark due to low coil voltage supply or poor compression for whatever reason. 

Just a question was it a pilot jet or a pilot air jet?

This guy is legit there’s plenty of bikes he’s sold.
Multi million dollar bike’s in his museum. He had one of the best carb mechanics working for him who retired and lives down in Florida now. 
Please watch the video: All the videos I have watched say that the Pilot Jet is the main reason for hard starts because they get clogged? Not one video on YouTube shows compression, or a weak spark or coil? I am not saying that you’re wrong? Maybe you should make a video and post it on YouTube? This video mentions MICRO DRILLING the Pilot. It’s funny that you said Kaplan’s finest mechanic is a nut job. LOL 

If the plot jets are clogged, they need to be cleaned.

Apparently he is then. Pilot jets come in increments of 2.5. Ie 15, 17.5, 20 etc. The mixture screw gives overlap from one size to the next. So if you need mixture setting between pilot jet sizes then you fit the bigger size and restrict flow back down to the desired size by adjusting the mixture screw to correct the mixture. 
Therefore there is no need to drill pilot jets. 
Oddly enough I think mikuni know what they are doing and how to design components that work given they have been making them for 60+ years and have been fitted to tens of millions of bikes from every major supplier. 

There is absolutely no situation where you need to drill out or fit larger pilot jets in stock carbs on a stock motor even when removing the airbox.
Your starting issues if fuel related are either due to blocked/partially blocked jets or passages that simply require a clean.

Zed 1015 could you please put that link up again:
showing web page not found!
Look I’m not trying to start anything on this thread and  I know they come in increments of 2.5. I wished you would have watched the video. This guy has built a lot of 4 cylinder racing machines and has won multiple times @ the Whip City Series and said that those 34s came in to lean from the factory just watch the video?
 I think a guy that was the leading mechanic from over  5 million dollars of Vintage motorcycles should be listened to? That’s all I’m going to say about this. Thanks 

I was told many years ago by a factory trained mechanic that you don't drill jets larger because the holes are contoured and not a uniform diameter all the way through. When you drill them out you are changing the shape and contour of the passage. That's why Mikuni made jets in varied sizes to allow fine tuning.

VintageKz@63 wrote:

Zed 1015 could you please put that link up again:
showing web page not found!

 

I didn't post a link in my reply but if you mean the one in my sig then it was for my air corrector jets which seems to have been lost .
Probably due to recent changes on this site..
As for your carbs possibly being jetted lean from the factory .
That won't cause the hard starting.
You should be looking at the carb jets and passageways for obstructions and also the choke pick up tubes and their chambers in the float bowls for the same..

Look guys I appreciate all the come backs on this subject. All I wanted to know is a REFERENCE on the diameter of the orifice of a stock pilot jet? How am I going to measure a diameter of an orifice? With a MICRO drill.
 I ordered a jet cleaner kit online you know the one that has different sizes of wire and I know don’t be poking and filling in the jet but not one fit in the pilot jet that’s why I wanted a reference in diameter. I’m not saying that the lead mechanic @Kaplan is right but maybe just maybe he broke down enough carbs to clean that he took carb cleaning to a whole different level by checking the Diameter of the orifice and had a REFERENCE of what it should roughly be. Zed 1035 thanks for the choke plunger I will be changing with a kit also. I also found this thread on google:While not "contoured," Mikuni jets are designed with specific internal geometry to optimize fuel deliverybased on factors like:

• Engine demands: Different engine types and configurations require different jet
• sizes and characteristics.
• Throttle position: The interaction of the jet needle and needle jet precisely controls fuel flow through the mid-
  range. o

In summary, while Mikuni jets are designed for precise fuel metering with specific internal geometries, the term "contoured" is not a standarddescription for them.

Oh the splendor of googling stuff.. Yes, Kaplan has a Super Cool building, ole-timey former production shop of some sort?? As mentioned by the other fellas though, no need to drill jets, just purchase. Isn't everyone a millionaire here? In these days a millionaire is confirmed every 6-minutes ha. Those BS34's had several jetting variations and applications/manufactures. Micro drilling, more like mini drilling. Thing is those twist bits offered normally range in sizes from 60-80 and are called fractional sizes, not nearly as accurate as what carb suppliers produce. Low-down, don't start drilling till you find the problem.