BZ's BMW Isetta 300's: Isetta - Transmission Rebuild

Friday, September 4, 2009

Isetta - Transmission Rebuild

Since the engine and transmission are mated, I'll be removing them together.

I've already removed the chain case and drive couplings. To further facilitate removing the engine, I'll also remove the carburator, coil, mud flaps, exhaust manifold, shifter rod, air filter cannister, and the eccentric sheet metal. After removing all these pieces, the last step was to remove the nuts on the engine mounts. Once engine mount nuts were removed, I got my knees underneath the engine and wrestled it out. I'm guessing the engine and transmission together weigh about 125lbs.

Engine and transmission removed.

Damage to the transmission cover.

Separating the transmission from the engine revealed worn splines on the input shaft.

The transmission has been separated from the engine and cleaned up a little bit . You can see the damage to the cover caused by either loose bolts or a broken drive coupling. Fortunately the damage is only cosmetic.

New gaskets, seals, bearings and other misc parts that will be used in the transmission rebuild. For the engine and transmission rebuild, I've decided to use Bill Rogers. Bill has an excellent website with lots of useful information on restoring Isettas. Bill also rebuilds Isetta engines, transmissions, chain cases, and brake cylinders. If you're in need of any of these services, I highly recommend him. The below photos of the transmission rebuild are a small fraction of the photos that Bill took during my rebuild. My experience with Bill is that he is very knowledgeable, meticulous, honest, and reasonable. That's probably why you may have to get in line for his rebuild services.