As I mentioned earlier, and as many already know, I'm in the midst of crafting a custom cylinder. Theres almost constant debate swirling around the realm of 2-stroke cylinder design and tuning. I'm posting this for any interested parties. The numbers on this barrel are pretty severe, the most peaked figures I've used to date. But I'm determined to squeeze as much blood from this 50cc stone as I can, so yeah...
Also: Illustrations are for reference, and Not to scale.
Monday, October 27, 2008
So, awhile back I put a 'shit-ton' of labor in my friend Shannon's Vespa PK50S. It was a really rare bike, and I helped make it go tres fast. Anyways, shortly after its return to Shannon (after much back n' forth) It was promptly stolen off of her street. A few years pass, and I spot a posting on the ScooterBBS looking for PK50 parts in Kentucky. I follow the links around, and sure enough, some fella has recovered Shannons PK50 for himself. I was pretty excited. The bike was pretty beat up, and will need lots of love. Shannon has moved on to larger machines since, so shes not interested in its return. Anyways, its nice to see the bike being rebuilt.
Monday, October 20, 2008
So I've been working on Liz's Vespa P200, and to my surprise things are actually going rather well. This is a bit of a surprise because Ellen's bike ,which was in definitely better shape, was very difficult to finish -particularly the electrical system. Liz's P2, though more banged up, seems to have dodged that electrical bullet somehow. We're currently waiting on some parts to make the machine abit more reliable.
I'm also turning my interest onto my own machines, particularly my Puch Newport II Moped. I bought it off of Scottie, an older fellow who was a race announcer at Vintage Days at Mid-Ohio, and a regular at Supersonic Scooters when I worked there. It was well-ridden and came with a biturbo pipe and had a ZA50 motor. This was about July 2004. It took me awhile to get to it, as I was still working with my first Puch, a Maxi-luxe I had built up for racing.
My set-up on that bike:
-Gilardoni 75cc Cylinder & Head
-Dellorto PHBG 21mm
-Customized Athena Intake manifold
-Homemade Electonic Ignition set up (bodged Tomos, Puch, Hero gear)
-13x45 sprockets for the track, 18x38 for top speed
-Michelin M29s Tires
Back when I built this racer, nobody was using any of this stuff outside of Rigid and the Dutch tuners who developed it all. I had to use online dutch translator to email 18 year olds about their jetting set-ups. Most American moped tuners were skittish about using carbs over 17mm. My point is that my bike is not nearly as radical today as it was a few years ago. When I finished the bike back in 2004, I went to the Decepticons' Moped BarBQue, which was my first moped rally (not scooter rally, though). I wanted to participate in their annual illegal road race, the "no-rules" race. The problem was my bike was 75cc not 50cc, a requirement to run. Still, on a borrowed 50cc machine it was a great run, with carnage, cops and intensity. I promised to return with my own 50cc machine.
It took me awhile, but when I turned my attention to the Puch Newport, I wanted to turn it into a easy-riding street bike that could still be competitive in the No-Rules race. I also didn't want to dump a ton of money into it, as I had done with the Gilardoni racer. After fiddling around with Will Laing's Tomos Racer, it occurred to me how similar Tomos and Puch equipment was. The Tomos A35 was superior to nearly every Puch cylinder, with a reed valve and four ports being standard. After a few measurements it dawned on me that a Tomos A35 cylinder would drop right onto a Puch motor with No modifications necessary. -At the time this was not common knowledge, though other moped riders had also discovered this , i.e. Bret Walker. So I built up my Newport motor, heavily porting the case transfers on the block and cylinder, enlarging the reed intake and intake ports. I sent the barrel off to be machined, raising the deck by 3mm to push the port timing for more potential. I adapted a manifold to fit the Tomos reed, fitted a dellorto PHBG 19mm and had Dave Force re-weld the biturbo to fit the tomos angled exhaust flange. I affixed a tall rear sprocket (38) and headed for Kalamazoo in 2006. That year the racing was less crowded, and my Newport performed well, clearing the pack handily by the second checkpoint. Unfortunately I was too excited to read the handout at the third checkpoint, and lost the race thereafter. Still, the bike did what it was supposed to and there was no 50cc machine at the race as fast.
Here's me at a scooter rally
(Roll in the Hay Hay) doing a burnout:
The Newport with that set-up had a Top speed of 48-53mph, depending on how that speed was measured. It was also reliable, and my sole source of transportation for several months. Still, I recognized the flaws and limitations of the set-up and looked to iron out those kinks. The first was the biturbo pipe. The header had a diameter that limited its torque, and the tuned length of the pipe limited the powerband. The second was the exhaust port of the tomos cylinder. The piston ring end-stops faced the exhaust side of the barrel. This limited the maximum width of the exhaust port to nearly stock. While raising the deck increased the overall port timing, power was limited by the exhaust port's small area.
My first consideration was to side-step this obstacle by installing a Puch piston with the tomos-style intake windows cut into it. Puch pistons havd ring end-stops facing away from the exhaust. But I would need a 2nd over piston (38.5mm) which are difficult to find. During this time of indecision, more and more Tomos cylinders were being installed onto Puch engines and it seemed to me that my next effort should considerably improve the bikes power. Gradually, the prospect of fabricating a unique cylinder for the moped grew on me. Working at Zoots Scoots, I was frequently in contact with Kymco Super 9's which are 50cc's and aggressively ported. From a few measurements, I determined I could build a unique and powerful cylinder using the Kymco Super 9 as a basis.
Monday, October 6, 2008
I feel the need to make some record of the things I'm working on, as over time lots of stuff gets discarded and forgotten about. My situation at present is that I've moved to Seattle about a month ago, and that I just a few days ago found a job. I've tried to stay busy with the job search over the last couple weeks, most working on my resume and portfolio. I also decided to do a topical self-portrait, imitating Barack Obama's 'Hope' image by Shepard Fairey. I've also been working on Liz's P200, which is in semi-rough shape and needs quite a bit of attention. I've also worked on my aluminum casting project, when money is less strained, I'll rebuild the furnace and try another melt & pour into the final model. More on all that later.