Lifan LF50QT-15 dies whilst idling

[raswan]

Hey guys,

Fiancee's got a 2009 Lifan LF50QT-15 scooter with 1500km on it that is on the fritz. Frankly, it's given us enough trouble over the course of its lifetime that I'm ready to sell it, but need to fix this one issue first.

Here's the problem: start it up, give it a little juice, and it will idle correctly for about a minute. Then, as soon as it revs down to normal idling rpm, it will die. Keep giving it a little juice, though, no problem. You can drive it around town fine, but if you stop for a light or stop sign, you've got to keep feeding it a little throttle, otherwise it will die. Doesn't matter if you run it for 5 minutes or half an hour, same problem.

I've adjusted the idle up a little, to the point where the rear wheel brake that keeps the back wheel from spinning during idle is overwhelmed and starts spinning. Fuel filter isn't clogged, and it drains fuel fine. Shot some carb cleaner in too, put seafoam in the tank with fresh gas, same problem. Friend who's knowledgeable about motorcycles suggested the autochoke, given it's behavior.

What do you guys think? I'm a relative noob here, but I can follow directions if they are clear enough and don't require super-exotic tools. I'm willing to spend a little to fix this so I can get rid of it, but I'm sicking of it sitting outside the apartment unusable.

I'm looking around too, but any suggestions for a place to get parts would be most welcome.

Thanks in advance!

[headonz]

I have a Lifan QT50 too and they are a well made scoot but you should do a little maintenance at least.

Pull the spark plug and compare with others here

www.xs11.com/xs11-info/tech-tips/maintenance/carburators/68-tuning-carbs-by-reading-spark-plugsthrottle-chop.html
www.4secondsflat.com/plug_chart.html

[gatekeeper]

Sounds like the valves might be a little tight. A common symptom for that is when it won't hold an idle or is hard to start when warm.

Check and adjust the valves. Here is a link to a video. Don't worry about taking off the fan cover to check the timing marks. Just make sure the three holes on the cam shaft line up like shown in the video. Set the valves to .004 inches intake and .005 inches exhaust.

www.youtube.com/watch?v=s0K-ytyjOFg

[larry001964]

Yep i agree with gatekeeper. Adjust your valves and you may not wish to sell it.

[raswan]

Thanks gatekeeper and larry. I'll try that first chance I get this week and report back.

[skuttadawg]

Actually the valves are loose . My Echarm would idle fine but just before coming to a stop it would stall but start right up . When the valves are too tight they make it hard or even prevent it from starting since not enough fuel and air get into the engine