Post by n4zou on Jul 29, 2011 18:12:49 GMT -6
After 13,000 miles my stator burned out one phase. I noticed it was not properly charging the battery. Battery voltage was only 12 VDC at idle with only a very slight increase when running the RPM up a little over idle. I knew then I had a bad stator but I double checked just in case the voltage regulator was shorting out that phase. I unplugged the stator output connector while it was running and checked across each of the 3 output wires. Voltage output was only 5VAC on one of the 3 phases. I went ahead and shut it off knowing it was going to be a while before I received a replacement stator. I went ahead and drained the carburetor and removed the battery. I then went in and order a new stator from the dealer I purchased my scoot from. It cost $44 + $12 shipping. After ordering I went ahead and pulled the Right lower body panel, muffler, and that air valve pollution control system connected to the exhaust port on the head. All must be removed to remove the right side engine cover containing the stator. I used some card board as a cover bolt placement guide because not all the bolts holding the cover on are the same length. Make sure you drain the oil before you remove that cover! Also be sure and clean the cover and engine area so you don't get road grime in the engine when you remove it. Removal was easy. (It was much easier than the 244cc CFMOTO engine.) After you remove all the bolts you'll need to look for some little tabs around the cover that allow you to pry it off without needing to pry on the sealing surfaces. Because the stator is mounted in this cover and comes off with it the magnets in the magneto will exert some force as you pull it off. (Also parts will not come flying out and rolling around on the floor like the CFMOTO engine.) 3 bolts hold the stator in the cover and 2 bolts hold the ignition pickup. You'll need to remove both. You'll get a new ignition pickup with the new stator so you will not need to worry about pulling new wires through the rubber plug. This is the easiest stator replacement I have ever done! Whoever designed this had to work as a mechanic at some point in his career.
Lucky for me the gasket remained on the engine and was not damaged. When I put the cover back on I just stuck it on and bolted it in place. I had no oil leaks at all. Here are pictures.
The bad stator. I thought I might one day rewind this stator myself. This photo tells me how to do that.
I've never figured out why the poles that burn up are not the ones that have windings shorted to the stator frame. They seam to always be the poles that are connected to the output wires.
Whoever wound this coil broke the plastic insulating material and went ahead and wound it anyway. This is what caused the stator to burn up.
This is the new stator. It was wound by someone that took great care to do it properly. I don't think this one will burn out before I wear out this scoot.
The new stator and ignition pickup bolted in the cover and ready to be put back on.
Note the pry off tab at the bottom right on the cover.
Here is the engine side. Note how the oil line is incorporated into the case instead of the external oil line used on the 244cc CFMOTO engine. That made this job so much easier and faster. While I was at it I made a block off plate for that air valve hooked up to the exhaust port. You can see it under the two shiny bolt heads at the right side of the picture above. Idle is much improved and I gained 5 MPG fuel economy. That block off plate was a pain in the ass to machine. It requires 4 precise 10 degree angles to be milled off and the ends must have a radius filed by hand so it matches the tube flange exactly. I could have simply cut the tube from the stock flange and used sheet metal to block off the exhaust port. I did not want to do that just in case removal of that pollution control system caused a performance problem. I am not in California so this system is not required in my state. If you are in California make sure you reinstall this system. I also had to make a spacer for the case bolt used to hold the valve to the engine. Yes; I have a lathe and mill for making special parts. I do not make parts for sale however, so don't even ask.
Lucky for me the gasket remained on the engine and was not damaged. When I put the cover back on I just stuck it on and bolted it in place. I had no oil leaks at all. Here are pictures.
The bad stator. I thought I might one day rewind this stator myself. This photo tells me how to do that.
I've never figured out why the poles that burn up are not the ones that have windings shorted to the stator frame. They seam to always be the poles that are connected to the output wires.
Whoever wound this coil broke the plastic insulating material and went ahead and wound it anyway. This is what caused the stator to burn up.
This is the new stator. It was wound by someone that took great care to do it properly. I don't think this one will burn out before I wear out this scoot.
The new stator and ignition pickup bolted in the cover and ready to be put back on.
Note the pry off tab at the bottom right on the cover.
Here is the engine side. Note how the oil line is incorporated into the case instead of the external oil line used on the 244cc CFMOTO engine. That made this job so much easier and faster. While I was at it I made a block off plate for that air valve hooked up to the exhaust port. You can see it under the two shiny bolt heads at the right side of the picture above. Idle is much improved and I gained 5 MPG fuel economy. That block off plate was a pain in the ass to machine. It requires 4 precise 10 degree angles to be milled off and the ends must have a radius filed by hand so it matches the tube flange exactly. I could have simply cut the tube from the stock flange and used sheet metal to block off the exhaust port. I did not want to do that just in case removal of that pollution control system caused a performance problem. I am not in California so this system is not required in my state. If you are in California make sure you reinstall this system. I also had to make a spacer for the case bolt used to hold the valve to the engine. Yes; I have a lathe and mill for making special parts. I do not make parts for sale however, so don't even ask.
..BAD TO THE BONE..
