Author Archives: Sophie Whiptank - aka Bart

About Sophie Whiptank - aka Bart

I'm just a bloke doing some stuff, the more interesting bits I post on my blog. Scroll down far enough and you'll see me riding from Melbourne Australia to Birmingham, England in 2014. But now I'm working on another project, a single cylinder motorbike engine at 2750cc!

Changing gear(box).


Now I have a mockup engine, I can experiment with different lean angles to see what looks best. I can also measure the height to see what sort of space in the frame I need. (80cm tall at it’s highest!).

The gearbox from the Toyota is next to the engine in the photo, and they don’t look too bad together. A fluid flywheel, cvt and differential would make for an interesting transmission, but unfortunately the flywheel rotates the other way on the car which adds complications.

A revised plan is to make a 2 speed chain box instead. It needs to be worked out and drawn up, but I think it’s time to change gearbox…. hmm…

Tap tap tap….


It does get a bit monotonous, but I like a job where you can switch off and let your mind wonder. It wondered, long and far – it was great! But now I’m back, and the 16 holes in the second case are tapped M10 right to the bottom. Thankfully Bob did the other set.

32 holes in total, 3 taps per hole. 96 tapping operations. Tap tap… ta-da!

And drilled…


Drilling the compression plate using the rotary table. The bottom of the barrel isn’t round, but rather a series of flats like an octogon. No idea why, that information Sir Roy probably took to his grave.

Anyway, the outside edge will be milled out to a round profile using the rotary table. It’s been a bit of a pain, taking longer than anticipated. But soon it’ll be all done and ready to transfer the hole markings to the cases.

Plate in situ for marking.


The compression plate has been bored and cut to fit on the barrel. Here it is clamped in place to allow the stud holes to be marked out with a custom made punch. Once we have the holes drilled we can fit a couple of bolts and cut the outside to size.

The plate will be used to mark the holes through to the barrel, which can then be drilled and tapped for the studs. Once the plate is bolted up, the job can be centred on the plate ready for boring.

It won’t be long before the two parts come together for the first time!