I have been running a Saito 125A for over a year and was very satisfied with it until a week back suddenly no compression… found that one valve spring on the rocker arm was stuck... touched it with a screwdriver and it came into place... What caused that to happen...? Anyways had 5 flights after that and all well.

Yesterday, tried to start it up, same problem and same solution.

Has anyone one faced a similar situation, any suggestions what needs to be done?

Thanks.

Bot a saito 125 1 year ago and just got around to break in. Was no compression. Turned it over maybe 50 times and finally got compression. Engine runs fine.