请教一些汽油机或摩托/割草发动机的问题

1.是因为看到harbor 13HP发动机的反馈：“Purchased this engine,took it home and mounted it in a atv I built. After filling engine with oil,I noticed a silver shine to the new oil. Since I build racing engines, I pulled the crank case bottom and found a bunch of metal fileings ,so took hole engine apart. the piston rings are a joke,and so was the cylinder hone,and vale job. just to see what I could do, I rehoned the cylinder, put honda pistons rings in it, and side polished the rod with arp rod bolts. to make a long story short and with the help of a high lifr cam, the engine now runs at 4500 rpm, and is making over 20 horse power. I have run the engine very hard with no problems for the last 114 hrs.” 该人改造及用本田活塞环后机器提高到20马力！
上面的honed the cylinder， side polished the rod with arp rod bolts，high lifr cam我不懂，请赐教。

2.我知道摩托/割草发动机多为2冲程单缸用混合油，但不知为啥这类机器毛病多？我的割草机是本田引擎，每次拉绳发动都要好几次，风门调节在发动前没帮助。似乎要化油器里有层油雾后，不多不少，才能发动。正确的启动和维护步骤?我忘了当初加油是否要混机油还是自动混的？清洗化油器的目的？