Hello, I am a sixteen year old student who has recently bought a scooter in order to drive around and get to places faster. As a cheap alternative i have decided to buy a cheap chinease scooter called Sym Symply 50. The scooter was in a decent condition from year 2012 with 28,000 milea on it. The scooter was a good runner for about a week, i could do 40mph+ on a flat road where as after a week it went to 15-20mph on flat. I also have a issue where the Scotter losses power on full throttle if the engine is turned on first time in the day, even warming it up doesnt help and i need to make sure that i dont full throttle it or it will stop. I am thinking that new cdi could help here as someone on youtube had same issue and that fixed it but id someone has a different fix let me know. Me and my dad have thought that it is due to its old milage, we thought that maybe it wasnt serviced etc so we changed couple of parts inside it. The parts which we changed were: spark plug drive belt engine oil air filter After the changes were made, there were little improvements where moped has wemt 30-35mph and i was happy of that however a week after the changes it went back to begin slow. I understand that it is a chinease and that it is a 50cc so therefore I shouldn't be surprised however i do think thag there is something not right with it. I am planning to buy new package for the transmission which wouls include stuff like new variator, weights, clutch and all of them, could someone tell me if it is worth to buy them or invest money in something different like carb etc.
Hello, greetings Wazil. Before you start splashing the cash I'd give the carb a good clean, make sure it's jetted properly so it's neither running too rich or lean. You've already changed the sparkplug, oil and filter which is good. There's definately something not right with it. Just because it's Chinese and 50cc shouldn't make you not be surprised. I would be very surprised if it happened to me.
Okay so Ive decided to watch a couple videos of how to clean the carb out in the GY6 scooters. The process looks very complicated and am unsure if is possible to do by me myself as my dad is now fed up with changing stuff for it. Ive decided to take a extra look at the problems and do extra research, I've attached links which should explain and show you the firsy issue with the bogging engine if that's what youd call it. This video is not as accurate but its the best one I could find. If i launch the engine it will run good, therefore there has to be enough air, fuel and a good spark. The moped will not stop if its on center stand like on the video, it will spin back wheel normally however what I noticed is thaf if i rev it up onn centerstand it wont bog the engine after Im on it however the speed issue is not fixed. I hope this gives you little more information and you could then give me your opinion again, I would consider a new unlimited rev CDI so could you let me know if that would fix anything as Ive heard that it also has performance boosts. Thank you once again.
It's always a bit scary the first time. But it's not that hard, if you are just organized and have that gentle touch and aren't to hard handed. This applies to most things you do on a scooter. 1.Take some photos as you progress," important first time you do stuff, later on you learn and can estimate where everything is supposed to fit" so that you know which cable/hose/jet/screw goes where. If you fix it right away it's not such a big problem. But if you don't Take photos, and pick all parts up a month, half a year or longer afterwards. It's easy to forget where everything was attached. 2. ORGANIZED. Have some old ice cream plastic buckets. With lids to organize all small parts in. So they don't disappear on the ground. Or end up in a vacuum. 3.TOOL-SET. Just fixing the carb doesnt demand a big assortment of tools. Screwdriver and pliers. If you planning of fixing more as things break down, have proper tools for the task. Hopefully dad has some tools. Otherwise I recommend buying a kit with great assortment. Usually cost around 100/150 eur/usd but its well worth the money to have all tools at hand organized. Instead of having everything thrown in a old toolcase. With alot of sizes/variants missing. And youll have the rest of your life. Cause it really sucks. To stop working, simply because you miss that exact tool/size. And it gets funnier when shit like this doesn't stand in your way. 4. I use freeze spray to blow the piping. Since it produces a mist, compared to just compressed air. So it's easy to see if something is blocked. And you also learn which hole goes where, since mist exist on the other end of that hole/pipe. Set this got crazy long. Hope you have some use of the info
Check the diaphram in top of carb for splits, jets, float level, airfilter all std complete and clean ? Valve clearance, 0.04" inlet and 0.05" exhaust. How fast do you really think it should go ? If you had a car that did 140mph would you drive it all the time at 140 ? You have a 50cc scooter that does 45 mph flat out and you ride it 45 flat out all the time !
Okay, cleaned out carb but that did not help I decided to then risk it and buy the transmission kit, bit of a different one as I wanted a whole of clutch not just the inside part without spring or anything. After changing the variator and clutch the moped runs fine, 30-40mphs on straight road. Thank you for all replies, and this person has helped me - https://www.youtube.com/channel/UCv8JIBfVdNoNLO9FKwkLg7Q
Hi, also worth checking your valve clearances. Lots of vids online - dead easy to do. That’s some miles for a 50 GY6, if it’s all original then it’s worth investing in a new top end and cam. The cams in these (and attached cam bearings) do wear so it’s worth doing every 15k. Only £10 for a cam and under £30 for the top end. you have resolved the issue, from what you said I was thinking it was the auto choke attached to the carb. Running well on the stand, then bogging whilst riding is usually indicating a rich mixture. When the choke breaks it sticks in the on position. This would cause a rich bog. once you have changed these you will be confident spannering on the GY6. Good bikes SYM’s - probably the best of what comes out of China. Everything GY6 is so damn cheap hence why it’s worth replacing rather than fixing. Instead of stripping a carb that’s done 20k miles just replace it, under £20!
