HS 49cc is losing the fight for survival...

[bigbutterbean]

There may be a slight variance between how often the manufacturer suggests changing the oil and how often the oil actually needs changed, depending on the quality of the oil you use. There have been plenty of times my wife's car has gone past 3000 miles without an oil change, although I do try to get to it when I can. As far as "riding hundreds of miles without thinking about the engine", if you take care of it, use good oil at the right weight, and don't abuse the engine by constantly over-revving it and trying to test and stretch its limits, you should be able to. My thinking is that when a premature engine failure occurs, 9 times out of 10 its user error or abuse. Reliability requires care, maintenance and proper treatment of the engine.

 

[bigbutterbean]

Minecraft, the carb bogging down is probably related to you removing the breather tube from the carb vent. I have heard a few others say the hs engine will not run correctly without the tube connected to the carb. If I were you, I would research what something does before removing it from your engine. That tube provides a function called positive crankcase ventilation (pcv for short). What pcv is, in essence, is sucking the blow-by (unburnt fuel getting past your piston rings and into your crankcase) and pushing it back into your cylinder during the combustion process. Some engines will run ok without it, others will not. I am betting that too much gas is leaking into your crankcase, thinning out your oil and causing your engine to overheat. My engine (a 98cc side valve) ran fine without the pcv tube connected, but once I found out what it was I reconnected it to the carb. I did it to improve my gas mileage, because all that unburnt fuel that's getting past your rings is being wasted if its not being sucked back out. I would reconnect it and see how it runs.