What makes 4 stroking on a cold start?

[DanielMaia]

Hi guys,

I am thinking about the 4 stroking on a cold start, on these china girls, because i see other 2 stroke bikes (yamaha DT, zundapp, casal, and much more) they run good, even in cold stars.

These china girls, with the motor cold, it 4 strokes a lot, the question is, why? bad quality?

When the motor is warmed up, it runs slighltly good, with no 4 strokes at all..

 

[Mind_Reader7]

Could be due to the fact that once metal heats up, it expands, thus causing sized changes throughout the engine.