A friend of mine has a VBB with a newere LML motor in it. It is a Vietnam resto, but surprisingly, it is one of the only ones I have seen that was actually pretty good. He's been riding it around for a year or so as a "Sunday driver". Recently, he took it out and noticed it was making a funny sound. Shortly thereafter, the motor siezed up solid. Not a soft easy sieze, but a "something mechanical broke bad" solid sieze.
So, he hauled it over to my garage, and I proceeded to try to determined what happened.
First, I got it up on the lift. I figured I'd look for the easy stuff first, and slowly dig into the motor. I suspected something in the top end, but I want to be thorough. So I'm going to start with the clutch, since that is easiest to get to. I pulled off the rear wheel, to get access to the clutch cover, and then pulled the cover.
Inside, the clutch looked ok. No exploded parts, nothing looking too wrong on this end. So it is time for me to check the other side of the motor.
Next, I pulled the fan cover off to get access to the flywheel. Nothing looked wrong with the flywheel.
So it was time to delve into the top end. I pulled the head cover off to get access to the cylinder head.
Next, I pulled the head. I was half-expecting to find a hole in the top of the piston, or bits of metal inside... but that wasn't the case. I did see a lot of scoring on the side of the cylinder. So, I'll need to investigate further.
Yowza! I pulled the cylinder, and saw this. This piston is TOAST! This is a serious siezure. However, that isn't the end of the story. What you can't see in this photo is that not only is the piston destroyed, but the crankshaft rod won't move either. It looks like we have a crank big-end bearing failure as well. It is looking like there was some problem with the two stroke oil, as in, there was none. This is an auto-injection motor, so I'm suspecting either a failure of the injector, or a failure in the oil line. In any case, I'm going to have to take the motor apart, and replace the crankshaft and top end at the very least.
Here we go... time to pull the motor apart. I took off the gear selector, the flywheel, and the stator plate. Then, I got all the case nuts and bolts off.
Motor cases cracked. The bottom end looks fine. The crank is stuck solid. She's a goner!
Now to pull the clutch, so I can get the crank out. However, no matter how hard I tried, I could not get the clutch nut off. After a lot of heat applied, a lot of air power tools, and a lot of swearing - I gave up. I pulled the motor, and handed it off to the scooter's owner. I told him to pull the clutch himself, and then we'll pick up the story from that point.
The owner has told me that he has gotten the nut off, so I'll be working on it again soon. Stay tuned for the next exciting chapter! Hopefully coming in a week or so, when I get the motor case back.
It's pretty common for an LML to run a big end. In the last two years, their cranks have been horrible. I've seen the ugliest conrods in them, scarred with what must be angle-grinding marks. Thrust washers absent or just one, nearly no side-clearance.
For $200 you can get a MEC or Mazzuchelli that will go forever, so why wouldn't you?