I have just got my 39 PWK carb from HPD, but do not have a clue as to the jetting. The carb came with a 165MJ and a 35PJ, and I have no idea if this is about right. I have an HPD pipe, muffler, RCR airbox mods etc, and 1mm oversize Wiseco.

 

ScrambledKiwi,

Depending on your altitude and temperature you may have to move the main jet up or down one size. Mine jetted quite nicely after a change to a 162 main.

 

Mike

I'm at sea level.

 

ScrambledKiwi,

You might just do just fine with the 165 main jet that's in it right now. I'm riding at 1500-2000 and the 162 seems O.K. to me.

 

I spoke with HPD, and they recomended to start with a 170 and work back. As we only have unleaded gas here, it makes a plug check very hard.