Mod? That’s rich! Currently I run a dirt bike motor, with the only exception being the RCE pipe, and deletion of the kick-start mechanism. The 36 PJ is what came with it, a 1996 motor I found brand new in 2000. Included was the ignition, which has not been altered even for timing from how Honda set it now 18 years ago. More stock than “Stock Moto”.
Easy to expect that the carbs run by the fastest guys are either Keihin PWK or PWM, possibly a Mikuni, but I have not spotted one in a while. Sizes 38 or 39. There may be a 40 or even a 41 on a PI motor or two, but I have no way of knowing that.