After removing the engine from the frame,
It must be completely disassembled, carefully so as not to break or lose anything.
Then, as everything is quite "grimy", we'll clean the parts one by one in the ultrasonic cleaner.
Once clean, each part is examined and sorted according to its wear and tear. This allows for an initial diagnosis of the engine's condition and thus its operation.
In the case at hand, we noted several things:
the lower engine oil seals were quite "dry". After about thirty years, this is quite normal for a two-stroke. But it also causes leaks in the lower engine, which naturally reduces performance.
Despite low mileage, the clutch linings were quite worn. This indicates a moped that has made many stops/starts (urban driving?) or operates in a country with many steep climbs.
The clutch flywheel was also warped (fall?), which unfortunately requires changing the entire part. Indeed, the rotation of this assembly creates an imbalance that is not ideal at the end of the crankshaft.
For the good surprises:
the top end was in very good condition; a simple honing and a pair of new rings should give this engine a "boost,"
the ignition plate and the magneto were... new. Adjusting the ignition, an electronic background, and proper break-in of the ignition cam will make it all viable,
the exhaust was well de-restricted... you can hear it quite well in the video...
The clean parts are then sandblasted and varnished so that the engine retains its "shine" longer. The varnish also makes it easier to clean the engine, as grease adheres less. After a few hours of work, we get this:
All studs are disassembled and reassembled with waterproof adhesive, especially those for the ignition which open into the lower crankcase.
New oil seals are carefully reinstalled so as not to cut or twist them:
And the bearings reassembled on the crankshaft... always use quality bearings. Naturally, the crankshaft clearances and its run-out were checked before reassembly.
The engine is then completely reassembled and reinstalled on the frame for the first static tests.
With the static tests conclusive, the remaining casings are mounted before the road test, the final step of our restoration.
This test will happen... as soon as it stops raining, it would be a shame to get it dirty 🙂
Once the test is complete and, no doubt, the final adjustments are made, "Mrs. 88" will be ready for service again!
For visual and auditory pleasure, here are some photos of this finished 88 and a static "engine" video at the "bottom of the page."