THE JUNKER ATV
For a while I had this cheap Chinese ATV that I picked up from a friend for almost nothing due to it being worn out. Over time the engine had gotten to the point where there was no saving it. Rather than try to find the correct version engine parts for this thing I decided to try and do something else with the frame. I removed the engine, leaving the frame and rear end. Original plan was to convert the thing to an electric ATV using a converted car alternator. After looking at that idea the alternator most likely wouldn't have had the juice to pull me and the machine with any real zest. The alternator idea would fit better on a bicycle. The next idea was to take another Predator 212 and work the thing into the empty engine space and turn this thing into a 4 wheel version of a minibike.
Since the frame was already stripped, I would have to fabricate a motor mount for the 212 that is in line with the sprocket on the rear end. Aesthetically and practically, using the ATV's old fuel tank was a better option since the 212 tank wouldn't fit anyway. The controls on the handlebars were utilized for the engine, being able to accept a generic throttle cable. The brakes were left untouched since really the only thing being done was shoving an engine in this thing. I used a plain centrifugal clutch for the driveline. The seat is crude, being a piece of 3/4" plywood.
During the first test I found that the drive sprocket was too small for the engine to pull the machine with me on it. Luckily I was able to source a bigger sprocket that fit this machine, allowing me to have a driveline with higher starting torque to the wheels. I ended up having to put inner tubes in the wheels since they wouldn't hold air. Once these things were done, we were off to the gravel.
With our first test runs down, we found a few issues with the build. The first thing was our driveline chucking the chain off most of the time when I tried to open the machine up. To help this out, I added some chain guide hardware and tensioners to help guide the chain better so we can actually enjoy this thing versus stopping to reinstall the chain. With the machine able to actually run hard, I was able to get some speeds clocked, finding that this deathtrap is able to run 30mph, probably higher than it was originally designed for.
Of course, just like with the KT196, I had to make some power mods to this thing. What else do you do with a machine that is already sketchy? Make it faster. Just like with the KT196, another Mikuni carb upgrade was done. I also upgraded the exhaust, rebuilding the assembly with better bends and no muffler, making it a little louder, sounding better and able to breathe better. With the carb upgrade done, I was able to make several runs and gain a few mph more, hitting 34 mph. I also gained quicker acceleration. I tried to see if I could eke a little more out of the carb with some jet changes but ended up dropping the performance pretty quickly so I had to stick with jets that are close to stock.
The next move for this thing is to repair the brakes. The whole time we were running off of the front brakes and even they were mediocre. Every time I did a test run I had to gauge when to stop early enough to be able to almost coast to a stop with the weak brakes. Restoring the rear brakes is paramount, this will involve replacing the master cylinder and pads, which of course Amazon provides the parts for cheaply.
