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Here is another update:

Flywheel arrived last night. I installed it right off. Comparing the two flywheels the new one was lighter and slightly smaller in diameter. The raised lug on the flywheel was a bit thicker but still when installed the air gap on the CDI trigger was quite a bit larger and more than a credit card. The engine runs so I am not going to worry about that. You can see in photos the difference in the placement of the lug. I was concerned in looking at this it wasn't going to be enough as it looks to me to be maybe 5 or 6 degrees. It was enough of a change and the engine now cranks and kicks just fine.

I have fixed a couple of other things like charging system quit which ended up being a faulty connector latch causing the connector to slide apart just enough to cause an open circuit at the regulator/rectifier.

The last remaining item is a surge at higher speeds. This is not a full misfire but I would describe it as a lean surge. If I had access I would put it on an exhaust gas analyzer but going to have to do this by the seat of my pants. I have a set of jets coming probably go up a couple of numbers and see what kind of results I get.

I have been over the cam crank timing twice. Runs too good for that to be a problem. Has anyone put a timing light on one of these engines? Where are the marks supposed to be?

I have a couple of pics of the fly wheel position and at first it looks like the key and and raised section on the flywheel are 90 degrees apart. I pulled the flywheel traced it out and located the key. So, with the diagram you can see that the key is greater than 90 degrees. I can leave this apart over night and do anything you think I need to figure out the keyway position.

Well haven't figured out the pics and my photobucket account won't let me upload. So to describe what I am seeing raised portion of flywheel at 12 o'clock keyway at 3:30.

HI Guys,

So here is my update. Basically this thing is up and running. I certainly have found plenty of things that would make this engine run lousy but the kick back on start eludes me at this point.

Here is what has been done so far:

Should be noted this scooter is a 2006 Lifan although the title says 2008. It was elderly owned, garage kept with 680 miles on it, has not been started for two years and free to me. It was taken to a "master scooter tech" who told them he had cleaned the carb, flushed the tank and that once running had an engine noise like a bad connecting rod 45 days ago.

I put this scooter right up on a bench which made it so much easier to work on.

Went back over cam timing, location of timing marks relative to piston TDC which were ok and and checked valve adjustment.

Checked again ohm meter and voltage readings on exciter coil and pick up coil.

Cleaned gummed up carb, plugged jets, stuck slide.

Flushed tank which had water in it.

Replaced fuel lines, filter and vacuum petcock which was leaking.

Replaced slipping starter clutch. The old one the allen headed crews were loose and had damaged threads.

Flushed out crankcase.

Replaced gear oil.

Inspect drive belt variator etc.

Repair ignition switch which had fallen apart.

So It now starts and runs pretty decent. Remaning items:

Variator is pretty smooth but tuned to get up into a higher "gear" to soon for me. My 125 Yamaha Vino is much quicker off the start.

Engine surges a bit at steady throttle cruising speeds. I suspect the carb is still lean but have not looked at the plug. Carbs are so cheap I may just buy a new one.

Still is the kick back on start issue. The kick back can really be felt when kicking and using electric start. On electric start it will lock the motor briefly. Does have a new battery. I have looked at the timing with both modules I have. The aluminum finned "racing module" and the original black module both are advanced when checked with a timing light. The timing does not change at all from idle to higher RPMs. When looking at the timing with a timing light the timing is between the 3rd and fourth mark on the flywheel and in the same location with either module. The lick back seems to be the same with either module. Most engines I have seen the timing is lower at idle and start then advances with RPM. My back ground is automotive so I am not sure what I should be seeing with this engine. Can anyone offer any suggestions here?

I have this scooter given to me that doesn't start after it sat for a while. An early discovery was the starter clutch slipping and not engaging. I can get it to engage sometimes. Here are the symptoms and what has been done to troubleshoot:

Does not start, kicks back and will pop out through exhaust. This seems like preignition.

The ignition system works and has spark

Tried a new module and coil

Checked cam/crank timing

Checked to ensure the piston was indeed at TDC when at TDC (T) mark on the flywheel

Checked stator and trigger using ohm meter

With meter in AC mode and with engine cranking (when I can get starter clutch to not slip) I have .5V at pickup and 70V at power supply from stator (that 70V seemed high)

With the spark plug out engine kicks fine. With spark plug in engine kicks fine. With plug in and spark plug wire connected engine kicks back.

With plug out I checked ignition timing with a light and it is pretty advanced. There is a T mark and F mark and two marks up from that. The ignition is firing at around those two higher marks. I might have suspected a sheared key but I checked that by ensuring the piston was at top and TDC lined up on the flywheel.

I did disconnect an aftermarket looking alarm system that I thought might have some odd effect on the ignition system.

I do have a starter clutch coming but I know it is not going to fix the no start.

Anyone have any thoughts on this? I am kind of scratching my head at this point.

On Monday I went for a bit of a road trip and picked up a couple of scooters I found on CL in New Hampshire. One of them a parts bike for my Kymco and the other a Yamaha Riva XC125. The person I bought it from was 15 years old and his grandfather gave him the scooter hoping he would fix it up. It had 4500 miles on it and missing a front fender, handlebar cover and did not run. The battery was dead so I could not even crank it over and with no kick start no immediate way to judge whether or not it had compression. I stuck a magnet in the crankcase and with no metal negotiated the price and into the truck it went.

Yesterday afternoon I had a few hours to putter around with it. The gas tank was off with a leak. So cleaned the tank then did a fiberglass patch. The gas tank smelled bad enough I did not even try to start it. While the fiberglass was setting up I pulled the carb off. The main and pilot jets were totally plugged and the plunger for the needle was stuck. The idle mixture screw had a tamper proof plug and oddly enough the screw head faces straight up. Gave everything a thorough cleaning and blew with compressed air.

The gas gauge did not work and the screws were missing for the sending unit. I still had a little time to mess around with this thing. So checked the gauge and it swept fine. Pulled the sending unit out and found the resistor wire for the potentiometer broken right at a soldered joint. Soldered that up and boom all set. A little trip to the hardware store and for 75 cents I had the missing screws.

After assembly and a battery charge it literally started right up and ran flawlessly on a quick run around the block. So, for $150.75 investment I have a running scooter that needs just a few plastics.

I have to say I have purchased now seven scooters in the last 18 months and I have been most impressed with the quality of this one. It is almost 20 years old and all of the rubber gaskets and o-rings in the carb were still flexible. The electrical connectors are high quality none broken none crumbling in my hand. The plastic covers are flexible and of a much higher quality then the chinese stuff.

Anyone riding these? Have a source for used parts?

I think I am kind of a fool for the retro look. I have seen some old Vespas I could buy but probably not a real smooth running rig.