[Thumper]

Originally Posted by Teklock

Unless these bikes are on the EPA's "Annual Certification Data" spreadsheet I would not believe it. Unless they are off road use only. https://www.epa.gov/system/files/doc...6-present.xlsx

Unfortunately, it looks like the engine mounts on the NC450 are very different. NC300 four valve engine (ZS174MN, that makes 25hp also seems very different. OEM 249cc ZS172FMM-3A has ~90mm between forward two mounting positions and ~160mm between the rear two mounting positions (this one):
https://aj1moto.com/collections/engi...-cb249f-engine


On the other hand...the PR250 (ZS172FMM-5), which is a 6 speed and has the balancing shaft, appears to have the same bolt pattern as the ZS172FMM-3A (stock engine on the Templar X):
https://aj1moto.com/collections/engi...n-pr250-engine

Even if it fits though, this is a modest upgrade: same hp rating, but with a sixth gear and the balance shaft.

So, unless someone has a good suggestion, I see no viable direct replacements for the stock engine besides the PR250, which isn't really worth the money for an extra gear.