Tyler6357
Well-Known Member
Hello everyone, I'm still very new here. Here is my situation. I decided to put a motor on my old mountain bike a few months ago. Unfortunately, I got a cheap 66cc/80cc 2 stroke China special ( http://www.ebay.com/itm/BRAND-NEW-6...7086035?pt=LH_DefaultDomain_0&hash=item35b867 efd3 ) It was the only 2 stroke engine I could find that would ship to CA. I have driven it only 500 miles and today while I was coming home it totally lost power and started backfiring. I adjusted the idle screw to get it to stop backfiring but it just has lost its power, I limped it home at about 11mph. I figured it was a fuel problem so I took apart the carb but everything looked to be working fine. I then thought the problem could be that the muffler might be starving it because I could hear loose parts inside so I took apart the muffler and tightened the screws that had become loose. However when I took the muffler apart I found several small medal balls that look like ball bearings. It is clear that these small balls have gone through the cylinder and out the exaust and got stuck in the pipe.
First: I took a picture of the small balls and pieces of metal that I found in the exhaust pipe. I took the picture next to a tape measure so you could see how big they are (see picture 2251). Anyone know what they are from??
Second: I took the engine off my bike and took the head screws off to check for damage to the piston and the cylinder. I noticed some nicks in the piston from when the medal pieces went through the engine. There are 2 on one side (see pictures 2254-2256) and 1 on the other (see picture 2262). You can see scratches down the side of the piston too. Does this piston look too damaged to use or are those scratches and nicks no big deal? The piston seems very loose. I can turn it about 25 degrees or so. I took a picture of it (see picture 2255), then turned it as far as I could and took another pic (see picture 2256). Also, the up and down has a lot of play in it too. Is this normal or is there something wrong? I should say that I had to zoom in with my camera to get the pictures of the nicks and scratches on the piston, they are actually very small (less than 2 mm wide) and less than (1 mm deep). The largest one (picture 2262) is about 2mm wide and at just over 1mm deep. They might look larger in the pictures than they actually are. Also, the cylinder surprisingly has no scratches or grooves, it only has one very slight nick that is so small I can barely feel with my finger. How this can be, I don't know.
I haven't taken the rest of the motor apart yet but before I do I was hoping someone could give me an idea of what I might be dealing with and what could have happened. Any recommendations on what I should do next? I'm not really a mechanic and I'm a total rookie taking engines apart. Is this really worth fixing or should I just get a new engine? It is only a $100 engine.
First: I took a picture of the small balls and pieces of metal that I found in the exhaust pipe. I took the picture next to a tape measure so you could see how big they are (see picture 2251). Anyone know what they are from??
Second: I took the engine off my bike and took the head screws off to check for damage to the piston and the cylinder. I noticed some nicks in the piston from when the medal pieces went through the engine. There are 2 on one side (see pictures 2254-2256) and 1 on the other (see picture 2262). You can see scratches down the side of the piston too. Does this piston look too damaged to use or are those scratches and nicks no big deal? The piston seems very loose. I can turn it about 25 degrees or so. I took a picture of it (see picture 2255), then turned it as far as I could and took another pic (see picture 2256). Also, the up and down has a lot of play in it too. Is this normal or is there something wrong? I should say that I had to zoom in with my camera to get the pictures of the nicks and scratches on the piston, they are actually very small (less than 2 mm wide) and less than (1 mm deep). The largest one (picture 2262) is about 2mm wide and at just over 1mm deep. They might look larger in the pictures than they actually are. Also, the cylinder surprisingly has no scratches or grooves, it only has one very slight nick that is so small I can barely feel with my finger. How this can be, I don't know.
I haven't taken the rest of the motor apart yet but before I do I was hoping someone could give me an idea of what I might be dealing with and what could have happened. Any recommendations on what I should do next? I'm not really a mechanic and I'm a total rookie taking engines apart. Is this really worth fixing or should I just get a new engine? It is only a $100 engine.
