I mean, I have seen and heard of some pretty dumb builds, but Nick takes the cake on this one.
If you are familiar at all with the Honda “Jobbitt”, you know it is one great little moped. Built up from a PA50I, it is now a lightly kitted urban blaster painted like Spiderman and can probably climb walls too. It’s not terribly fast in its final form at 43 mph, but it revs right into the powerband and pulls like your Mom did last night (Boom.) And also like your Mom, the Jobbitt looks like it shamefully crawled out of the gutter this morning. Exposed wires and stickers all over the place, but still works just fine. Can’t brake worth a damn though. Camino mags are pretty but pretty don’t mean stop.
Not satisfied with creating the Most Fun Moped Since Ever, Nick wanted to create something even better. 6 Million Dollar Man Style. But not Gangnam Style. So over PSY. This build would use unconventional parts. Homebrew parts. Probably illegal parts. And parts made by imaginary friends. Speaking of which, Nick needed some machining done for the first part of his build and being a
8’3″ furry creature of legend machinist, I was only happy to oblige.
The primary challenge here was to remove just enough material from the case and the new kit to be able to make sure the transfers opened at the right time AND prevent head contact. The case had been welded on to add material for opening up the transfers and to give more space for the kit.
First order of business: Machine the case halve mating surfaces. Some quick work with the end mill did the trick. Next, we had to machine the base area on the case.
Only having a simple vise on the mill meant we had to carefully position the case in the vise and clamp down, ensuring the case was square/level/parallel to the cutting surface, etc. and would not move during the milling! With a C-clamp to hold the case halves together and slow work, I was able to remove about 1 mm from the base.
Thanks to very crappy cast aluminum, the added welding contained a lot of voids that will likely rear their ugly head when Nick is doing the transfer porting. Some Quicksteel or JB weld can take care of that, but it was still a little disappointing to see during the milling process. Thankfully the careful work and constant checking against level made sure we had a flat, perpendicular base for the cylinder to mount to. We removed the case halves from the vise and with the milling on the case complete, we installed the crank into one side and checked the clearance of the unmodified kit , making sure it would mount cleanly and not impact on any unmachined features. We also double checked the distance we needed to mill down the base of the cylinder so that we would not go over.
With that complete, we clamped the cylinder onto the table of the mill and started chipping away. I knew I could be a bit more aggressive since I was clamped directly to the table instead of the vise but took small bites anyway. Good thing too, because we actually were 0.5 mm away from complete, checked it briefly and discovered we were spot on already!
One bit of machining to be done was overboring the stud holes in the cylinder and the head so that the slightly wider Honda case stud holes would allow studs to line up with this new case. A bit inelegant of a solution (says the guy posting Your Mom jokes on a blog) but it worked and besides some transfer work, the Heart of Jobbitt 2.0 is ready for assembly.
Stay tuned Moped Kids! Next we will cover mockup of yet another part of what is making this one of the more insane builds of the year! Nope, I’m not going to tell you. You will just have to check the blog incessantly.