Basic chinese bike troubleshooting guide

Hi everyone!Since I wrote a couple of guides relating to our experiences with a 110 chinese quad and a 250 dirt bike, I've had a few queries from people who have had some difficulties with their bikes. I'm not an expert in any way, nor a trained mechanic, but I've had some experience with keeping our bikes running and troubleshooting issues as they've happened. I thought that I'd put them down into a guide that may help other people. As I find more information and resolve issues with our bikes, I'll add the details to this guide.At the moment we have a 110cc Quad, a 125cc Quad, a 125cc Pitbike and a 250cc dirt/trail bike in the family. A friend has a 110cc Buggy.Bike brands vary, but there are zongshen and loncin motors in them.Anyway, here are some queries I've received that may be of help.Here we have a Quad that is proving hard to start and keep runningHiI was hoping your still doing your guides to 110cc quads if so I've just bought a second hand one put a new battery in it. It starts only with full choke and ifI turn the choke off it runs for about 15 seconds then stalls.I have had it going around the yard but it stalls every time after a short while. Im suspecting its the carby, any help would be great thanks. Here is my response:Hi Mate,Sounds like a carby problem for sure.Running on full choke and then dying when you turn the choke off sounds like there's just not enough fuel getting through.You can take the carby apart and give it a good clean, make sure nothing's blocked and fuel can get through. You can have a play with the mixture screw on the side of the carby as well. You never know, the previous owner may have fiddled and set it wrong. Note that there will be two screws, one for idle speed setting, the other for mixture. If you don't have any luck with that, a spare carby will only cost you around $15-$25 from the bikes spares category here on ebay. Do a search for 110cc and have a look to see that yours looks similar to the one on the listing. Best of luck mate and let me know how you get on..Here is another Quad that is proving hard to startDear Farnk666, Hi, Noticed your guides and am wondering if you could help me with my 110cc quad which is approx 3 years old and won't start at all. I have replaced coil, spark plug,