Help needed for DIY engine

[White stallion]

Help needed for DIY engine Hello folks I am building my first 66 mL two-stroke engine I’m looking for some info on the crank case the question being would I be just as well off to go with a standard crank from eBay or go through arrow motorized bike for a balanced crank

 

[White stallion]

Also don’t know much about short rod or long rod

 

[Chop-chop]

Depending on the length of rod, make sure you pick the correct piston should you ever need to replace it. There are two different types with different pin locations on the piston body.

You do get what you pay for. The problem with the cheap Ebay bottom-end is they won't be balanced to high tolerances hence giving you vibrations at higher rpm. Once you start getting past the stock 2 - 3 hp, how well balanced the crank comes heavily into play on how much more efficiently the power you'll be making...