Day 59 - C110

What is old is new again. I've mentioned that my first bike was a lowly Honda 50, model C110. Because it only had 5 blazing horsepower and I was always riding like it had much more I became an expert at rebuilding the engine.

It was an overhead valve engine which was advanced for a small bike of the time but was overshadowed by the later overhead cam engines soon to follow. The big difference is that that the cam is down in the engine block and the valves are opened by way of push rods and rocker arms.

The Achilles Heel of this setup is the pushrod. It's long and will flex under load at high rpm. Then it breaks stopping all forward progress. Also, because it has mass, at high rpm the momentum can continue to keep the valve open when it should be closing. Flexing leads to breaking and the momentum, known as valve float, causes the valves to hit the top of the piston with catastrophic results.

Breaking pushrods became such a common experience for me that I carried a spare set taped under the seat and could replace them in a matter of minutes. A feat I proved while crossing the Bay Bridge as cars and trucks whizzed by by only the tiniest margin.

Good judgment comes from experience and experience comes from bad judgment!

I was the most experienced C110 engine overhauler on the planet! I took apart the top end and replaced valves. I took apart the bottom end and replaced gears. I rebuilt it more times than I can count and became quite a good motorcycle mechanic who could diagnose problems quickly and wasn't afraid to take things apart. Friends came for advice and with their own machines.

Fast forward to today and, voila, another C110 engine!

You will notice that it is in several small boxes. When I worked in dealerships people would come in with a long tale of woe. All about how they were going to fix it felt confident because they had once changed the spark plug in their lawn mower but now it was just too much for them. Did we think we could reverse their incompetence and make it run again?

We would look it over for signs of gross destruction, there were usually none, pull out the Honda Flat Rate Manual and show them the standard cost.

They would be so happy that we could restore their bike to running condition and didn't make them feel like total toads that they would thank us for our help. We would be thinking that they had already taken the engine out of the frame and torn it down, thereby doing half our work for us. If they had lost a clip or a bolt we had the entire parts department only 10' away. This was easy money!

Now I am looking at an engine I know all too well and all I have to do is put it back together like a jigsaw puzzle. It's cleaned up and ready to reassemble so first thing tomorrow morning I'll be out in the garage, right after I finish my oatmeal.

Stand by for further announcements.

---

Make my day, tell a friend about this blog!