This engine was fitted, I say 'fitted', it was hanging out of my series 3 LI when I bought it. The engine was siezed and it wasn't in the best condition, so I decided to find a 125cc engine to fit and register the scooter with.
Before I bought the replacement engine, I started to strip this one in the hope of it being a relatively simple rebuid/freshen-up. However, it wasn't. The stripdown took literally a month of Sundays. I've never come across an engine that put up so much of a fight. I actually belive it had been sitting in a river or a bucket for 20 or 30 years.
I wanted to start by removing the flywheel and stator plate. The flywheel had corroded itself to the mag housing. After chipping some of the mag housing aluminium away, the flywheel could then be removed using a puller. The stator then came out with no problems.
I then removed the spark plug and the head. The plug came out easily, but the head had corroded around the barrel studs and no amount of heat and prying could get it free. To remove the head, I broke the majority of the metal away, then used a hacksaw to cut down the sides of the studs. Doing this, and a bit more heat, eventually freed the remainder of the head off.
The next job was to remove the barrel. I cleared the cooling fins out, soaked the studs and bore with penetrating oil and reached for the blow-gun. After a little while, the barrel started to wobble and the crank started to free up. A few more squirts of oil got the crank and big end loosened up, but the piston could not be persuaded to shift.
At this point I didn't expect to save much, if any of this engine, so I got the drill out and fitted a hole saw that would go down the bore. I used this to drill through the crown of the piston and the piston rings could then be pried out. I continued to drill down until I hit the gudgeon pin, then used a chisel to break the piston skirt up which allowed me to lift the barrel clear of the crankcase.
Time now to remove the mag housing. I wound in the T-bars which then promptly stripped the threads out of the housing. I fired-up the blow-gun again, started to gently tap the edges of the housing which led to lots of broken pieces on the worktop and no movement.
I took a break from the mag housing and started stripping the chaincase down. There was no oil inside, but everything came off nice and easily, which was nice. I decided to use the crankshaft as a drift to remove the remains of the mag housing. I got my biggest copper hammer, fired-up the blow-gun - again, then started whacking. Eventually after about 10 minutes, I saw some movement, and shortly after, it was all over
Time now to strip the gearbox down. I removed the endplate and pulled out the gears and gear cluster. For some reason I decided to count some teeth and it was to my surprise, that what I had, was an LI150 Special or 'Pacemaker' gearset.
The stripdown was almost complete. All that was left to do was strip the chaincase cover and remove the silent blocks. There is an old saying, where there is pleasure, there must come pain. The Pacemaker gearset was the pleasure and trying to remove the silent blocks was a whole load of pain. Even with the proper tool, these were complete agro to get out. After coming this far, the last thing I wanted to do is fracture the casing where the mounts locate. Fortunately, and after stripping the thread on my tool, the mounts were removed.
With the casing fully stripped, I had to helicoil one of the M8 chaincase stud threads and also remove the other which had been sheared off. This job was completed with no dramas. I then put the cases and parts to one side with the vision of using the cases to make a fast engine.
A few months pass, and while I was in the process of rebuilding the 125 engine, I sent the 150 cases away with a new mag housing to be vapour blasted. Unfortunately, although nice and clean, the cases are quite badly pitted, so I'm going to rebuild back to a standard 150cc but using a 125cc gearset. I still want to build a fast engine, so I will keep the Pacemaker gearset for that.
Now you are all pretty much up-to-date and if you're all still awake (lol), your prize is lots of pics
Thanks for reading,
Jim.
Here is the engine just after removal:
Trying to remove the flywheel:
Flywheel removed:
And off with the stator:
Manky spark plug:
Head before removal:
Losing my head:
Cutting down the side of the studs:
Mmm, nice:
Brutal piston removal:
Rings out:
And off with the barrel:
Remainder of Piston removed:
Chaincase cover removed:
Compressing the clutch for circlip removal:
Clutch assembly removed:
Front sprocket removed:
Looks like a shim, but it's the rest of the oil thrower plate:
Rusty Lee:
Siezed rear brake shaft removed and bent brake arm:
Mag housing removal:
Finally out:
And out with the crank:
Hmm, someone has been here before:
A few random pics:
I'm planning on going on the Kickstart run on the 11th, so that would be its first outing if I get it in the scooter in time.
It will however be ready for fitting and firing-up this weekend.
