Project Blue… Still working on it. Slowly.

When you work on projects like this as a hobby and still have a full time job, you have to be willing to accept the fits and starts. In August, I was certain that I would have a couple months of solid hobby time to make progress, and I did. That’s when other factors come into play. I had planned on getting the cylinders installed and was working on the rolling chassis milestone. Let’s start with the latter of those two.

Rolling Chassis

It’s always a good feeling to have the driveline, suspension, and wheels all installed on the frame. it lets you begin to imagine a completed project and is something to look forward to. Blue has been very close to this stage for a while now. I have the front end installed to the forks, the motor (short block) installed, gearbox and swingarm installed. I already wrote about the rear drive issue in the previous project update. The part is off to be corrected and I still have my spare on the bike. I am hoping to get the original back before I need to move too far ahead.

(update: it got done.)

Cylinders

The cylinders are another story. For this project I am using Wossner high compression pistons. The are a straight replacement for original pistons and not too different from those in the Siebenrock kit I used on Project Red. One key difference from the OEM pistons is the design for the wrist pin installation. BMW wrist pins extend beyond their bore on each end and are grooved to accept a standard outside snap ring. Easy to install and remove. Aftermarket pistons all seem to use a continuous constance lock ring instead. This allows for a shorter wrist pin, and lower weight. The lock rings are the problem.

I am sure that they are easy enough on a full size auto motor where you have larger diameter wrist pins, but on the airheads, they are a royal pain. Normally, you install one in the piston before you put the piston in the cylinder, then you put the second one in as you install the cylinder on the motor. I planned ahead a little on this and installed the rear lock ring on each piston so I would not be competing for space with the motor’s bell housing. Still when you are installing the front lock ring, you need to contend with the two front studs that hold the cylinder to the motor. If you don’t bend quarters with your fingers in your spare time, you are going to have a rough time getting these installed.

I fought with one for long enough that I gave up since the Threebond on the cylinder had essentially cured and needed to be cleaned off. With all the attempts and methods I tried, I wound up doing a good job of buggering up the pistons surface finish. I eventually decided to order another set, since I don’t want mangled pistons in this project. Yes, they would be fine to use. Yes, I know that nobody will ever see them unless something goes catastrophically wrong. Even so, I was not happy with how they were looking and opted to order a new set. these will get used in one of my next projects.

While I waited the six weeks for the new pistons, I made many attempts at fabricating an install tool for these clips. Some got close to working, but not quite good enough. This is just too much for a printed tool. Finally, I found an install tool that does work and works very well. It consists of a sleeve to compress the ring and a plunger to push it into the piston. Simple and straight forward.

Now, I have the cylinders installed and torqued.