I am new to the mechanical side of quads, but I bought a Redcat MPX 50 just so I can start learning about them and what not. It was running fine, but then one day my roomates drove over something in the garage and he heard a loud pop. Then the bike wouldn't start after that. i checked the spark plug it had someone came loose, so I screwed it back in, now it dounds like it wants to start, but won't turn over. Any ideas, because I've got nothing.

 

alright, so it won't turn over, go ahead and check the voltage across the battery. check fuse and replace if applicable on positive cable. if battery/fuse is good, check wiring from battery to solenoid to starter. check ground wires also. turn key switch on, try to start, if it fails, try jumping the solenoid posts with a screwdriver to see what you got there. if it turns over then and won't start, check for spark. checking for spark: pull spark plug, attach to coil wire, ground to jug/head, crank/turn engine over and watch it. let us know..........

 

here's a website that'll help you out.
Kid ATVs | Cheap ATVs | Jetmoto ATV Parts | Online ATV sales | Kids 4 Wheelers | Hastings Minnesota

also, here's a manual that has a few tips that can help you out too.
http://www.kidatvs.com/RedCat/kmx50_manual2.pdf

just FYI, on the first hyperlink, when you click on the different quads to look at the specs, you'll see a hyperlink on the right hand side that says "manual". that's the owner's manual for each model/style quad. pretty handy for the chinese ones.....