I got a 2004 crf 50 for my son a few months ago. Today I went to start it cold after sitting for about 2 weeks and upon start up a smidge of smoke came out of the exhaust. Bike runs great so is this something normal for these or is there an issue? I ran the bike up the street and back. Shut it off and started it again and no smoke. Motor wasn’t “hot” when I restarted it. Also motor seems to have plenty of juice imo. I don’t really have much to compare it to as its the first one I’ve ever owned.
Remember that the engines are flat, so oil can leak past the rings and valve stem seals while cooling off from the last time it ran. That little bit of oil plus extra fuel from the choke could cause some cold start smoke. Don't worry about smoke from a Honda engine until there's a loud knock or excessive smoke during normal running. Those engines are tanks, why do you think that there are so many copies from third-rate manufacturers that run forever in poorly maintained pit bikes?
I actually think I figured it out. I had it on a big bike MX stand because I had to switch out a rear tire tube and it sat at an extreme angle for 24 hours (front tire on ground and the rear in the air. I put the tire back on and then started it. I’m thinking a little oil settled where it shouldn’t have.
