Carb jetting and tuning for mods is all about experimenting, so you could try the Canadian needle with your stock Y-0 needle jet. Yes, it is recommended to run that new adjustable needle with its supposedly matching 336-Y-0 Canadian needle jet, but like I said, this carb tuning thing is all about experimenting to find what works best.
If you understand how needle jet sizes are designated, then you would know that the Y-0 indicates the orifice size of the jet. So, since both of these jets are labeled Y-0, what makes them different? The number of air bleed holes down their sides. The stock Y-0 has rows of 3 and 4 holes, the Canadian 336-Y-0 has rows of 4 and 5 holes. So technically, that makes the 336 version leaner, but combined with the much richer Canadian needle, the overall result is still a richer running combination than stock.
The 5IX11 Canadian needle is so much richer because its shorter. The stock 5HX12 needle measures about 50mm from the clip slot to the tip. The 5IX11 measures about 50mm from its top clip slot to the tip. That means running it in its center slot will raise it 2mm compared to the stock needle.
