I got a 2005 Baja 50 give to me and i had to buy a new carb and it wouldn't start. Its has fire and gas. I checked the compression and it was 50 psi so i removed the piston and checked the valves and they were perfect but the cylinder was in ruff shape. looks like it had got water in it and it had caused the rings to seize and i got the rings freed up and took some sandpaper to the cylinder to clean the rust and bad spots up since it is pitted. When reinstalling everything i didn't have a gasket for the bottom of the cylinder where it meets the block so i cleaned it and put gasket maker. I was worried that the gasket maker Silicone being thinner might make the piston hit the valves or head but it didn't. After getting it back together i checked the compression and its 115 psi. It now starts and runs but seems a little weak. Now i could be wrong and just be being silly cuz i rode it and I'm 230 Lbs lol and limit is 100 Lbs. With me on it, it struggles to pull out on even the smallest slope but seems ok with kids. My question is, is 115 PSI to little for a 50cc? Ive been told 175 psi is what it should be. Ive been a mechanic my entire life and with cars I know 120-190 psi is good depending on the engine.

 

115 isn't too bad. These don't have a lot of power to begin with.

 

90 to run, 130-140 is excellent...don't think I've seen 175...