BSA Triple Engine Rebuild

After many enjoyable summers on my beautiful BSA Rocket III, I felt it was time to get down to some serious maintenance. I initially thought that I would be able to get away with just doing a top-end repair: new rings, valves and valve guides. The advantage of this is that it can be done without removing the engine from the frame. So, on a cold Sunday a few weeks back, I pulled off the tank, the mufflers and the carbs, and then set to work on the engine. After accumulating a small pile of bits, I was now staring at the pistons. After doing what I could to clean up the head and cylinders, I sent them off to two different shops. My British bike guy was to check out the head, and install new valves and valve guides. I sent the cylinders off to a machine shop to hone the cylinders and bead blast them.

Unfortunately, upon inspection of the pistons, there was enough play in the connecting rods that I decided that I needed to do a complete engine rebuild, This is a daunting prospect for me. I have owned my bikes for years, and do work on them, but I do not by any means consider myself a great mechanic. The biggest reason I do this is that is expensive enough to buy the parts for a vintage bike without the added money to pay someone to take it apart and put it together for you. So, with the encouragement and help of my motorcycle mentor Louie, we pulled the engine out of the frame and lifted the approximately 200 pound engine onto the workbench. I think I knew this day was going to come, as I bought an engine stand I could bolt it to, to make it easier to work on.

Probably the most difficult part of the takedown was removing the clutch hub, which I suspect has not been off the bike since it's manufacture in 1972. I used 3 different gear pullers, and ultimately a torch and hammer to get it off. Fortunately, while I trashed the hub, the shaft is still in good condition. After getting a line on someone who could do the crankshaft grinding for me (there are less people who do this every year) I am now in the phase of cleaning all these bits to prepare for my reassembly. Wish me luck!