The Bike Build (Part 6)

And now we are in the home stretch.  The final assembly stage and test rides, the debug and the final joy of having a bike.

And here is where we left off. Most of the major components have been bolted to the frame, the electrics mostly tested, but still more to go.

Because this was the early 90s, I suspect some of you have figured that these are scans of actual photographs, No digital camera when this was done and as a poor engineer I did not really take too many pics of the build, so you go from the picture above to the one below.  Now don't be fooled, this is not the completed bike, this is a test fitting of the panels, tank and set just to make sure it all hangs together, and apparently it did with little adjustment required.

This picture is amusing as this is a picture of yours truly, when I was much younger, doing something extremely complicate and clever no doubt. 

With this as the final product; not too shabby if I say so myself. I was very happy with the way it had come out but it had not run yet.  It needed to be transported back to my flat to do the final small bits and bobs, tax it and get it running. 

So onto Dad's trailer it went and we ran that thing the 150 miles to my flat.

At this point, we got it off the trailer, finished the last pieces, put fresh petrol in the petrol tank, oil in the oil tank (it's a 2 stroke engine with a separate oil tank, rather than running on pre-mix), and fired it up. Eventually it ran.

In all its glory!

There were two main bugs that needed resolving to get it to run right.  I had done a few local trips with the bike, but it was never a bike I expected to go any distance on. However I did decide to travel from Swindon to Maidenhead on it one day, and that did not end well. I got a few miles out of Swindon when I felt my leg getting hot and wet. Apparently the thermostat had stuck and eventually the thermostat housing  seal bust, spraying my leg with hot water.  I disassembled it on the side of the road and threw out the thermostat. That solved the immediate issue but I had to head home because the thermostat housing now leaked.

The second issue was harder to solve and frankly never really got solved.  This was a TZR125 engine and it had a power valve. What is a power valve, I hear you ask?  It is an assembly on the exhaust outlet of the cylinder that changes the effective size of the exhaust port.  This allows what is essentially a puny little engine to produce more torque at lower revs, and more horsepower at higher revs, just by changing the aperture size of the port.  Mine did not work.  The valve itself rotated, driven by an actuator.  The actuator worked just fine until it was connected to the controller. The controller was connected to the throttle and it seemed to work fine, but all connected together, it completely failed to function.

I tinkered with this for months, and eventually settled on pegging the damn valve about half open to give me the best performance I could get with a static port. I tried replacing the actuator, the controller, everything I could think of but I never could get it to work right. 

And that is it. I used the bike regularly, passed my bike test on it, and eventually sold it on, but it was a fixture of my life for a while and I loved it. This was the only bike build I have done so far in my life, but it was a fun learning experience, I do not regret it. I did sort of wreck the carpet in my little flat, but its just the price you pay for the fun and experience. :)