Come get a taste, Mantooth!

         So, I am so far back on updating this thing I forget where to start. Probably the funnest thing to talk about would be the awesome work Michael Mike and Phil did on my Simonini race exhaust. Getting ready for the race at the end of July, I was scrambling around to get everything sorted out. With the new subframe in place, the exhaust was not mounting up correctly, running short on time with my "job" & all, Phil offered to sort it out only if I brought the whole bike down to then set it up. With only a few days left, and the welding taking a day or two longer than expected, I grew somewhat concerned. Pictured at left is the exhaust such as it was in the original configuration. My concerns were solidly laid to rest when I drove to Georgetown to collect Plan B. Pictured here is the exhaust in its utterly transformed state.

       Truly the pictures do not do justice to the Naz's tight welding and metal work, nor do they highlight Phil's crazy powder coating. Nice Work Fellas! It is very good to have such talented and generous friends. So with the pipe and sub-frame completed, here's a look at Plan B after her 2010 makeover:

 

Dang! Some advice for future sub-frame builders:

1. USE A JIG. warping will occur.
2. Save the old sub-frame.
3. Lots of parts had to be customized or ordered special.

        The belt is a weird extraaa-long AX51. I wasn't sure of the dimensions i needed, so i just ordered several and tried them all until I had a winner. Also, the brake cable is custom too, again extra long. Speaking about the pipe again, there are absolutely zero ground clearance issues. When i lay the bike over on its side, the first contact point is the pedals in the vertical position. Also, the twin silencers are begging for flamethrowers to be added. That may be a special Team Nerdspeed edition ....

          So in spite of all the work done, Plan B was still not happy come race day (carb/fuel issues) and I ended up borrowing Naz's Lomos for the race. Practice and qualifying went well, Naz JJ and Travis all pushed towards the front of the pack. Phil suffered a breakdown in practice and Travis was having considerable trouble with the new disc brake front end on the hobbit. In the qualifying run I thought I had a legitimate shot at a podium finish with so much competition on the sideline, but NASCAR pit crew team efforts in the paddock got Travis' machine back in action, and I decided sharing is always the right thing to do, so Phil took the Lomos for the second qualifying run and the race. The plucky and reliable Lomos kept its head on a swivel, which is what you do in a vicious cock fight. This is me keeping the hyenas at bay:

For awhile now, Liz & I have been trying to sell her Vespa P200e. It wasn't going very well for along while, so after a new paint job didn't work, and dropping the price tag several times, we had some fun & made a commercial:
 

Less than 36hrs. later we sold it to a very excited girl and her friend who was from ironically, Columbus.

Wind beneath my wings

           Everyone has an inspiration, a goal, something they want really badly, or want to be with every iota of their being. When I get coffee, I see dudes that are definitely attempting to become Johnny Depp, or Demetri Martin or that really, really want to fall into an Ocean Pacific T-shirt design from when I was 12. When I was 12, I wanted to be Chuck Yeager. I wanted to shoot down Messerschmidts with my Mustang and test-fly rocket planes. Now that I've done all those things, I think I want to be Jan Thiel. Why? Because Mr. Thiel designed probably the blindingest most amazing race engine to date. Now, its possible that he has some competition by way of Yamaha's direct injection boat engines, but I can't find anything with wheels that holds a candle to the RSA. Even the Boffins at HRC & KTM are struggling to match this beast. 

           Some years back the arms race in MotoGP 125 was a dead heat, with bikes from a handful of marques pretty evenly matched. Piaggio / Aprilia was getting feedback from the riders that they wanted an engine with more torque in the upper midrange. Tuning possibilities exhausted with the current RSW engine, they sought to develop a different style of engine, and recruited legendary 70's 80's GP engine tuner/designer Jan Thiel, who happened to be alive and interested in the project. With his genius and Piaggio's resources, the results were unconventional and powerful. The RSA is a 125cc Transverse Rotary valve engine that makes a blistering 56.5hp, with more torque and 3.5 hp more than its reed valve predecessor. Without a new material (carbon this, silicon that) having been invented, a 3.5hp gain is pretty significant in a race class where the blood has been squeezed from the stone for decades. 

              Like many, when I first got into bikes I presumed that the stock rotary systems on my Vespas were garbage and that aftermarket reed valves were the only way forward. The truth as I'm learning is that reeds are the easiest way to access 97% of available horsepower, but that at the tip top, rotary is still the Hp King. Why? Because when a rotary valve opens there is no obstruction (like a reed cage) between the crankcase and the carb, optimizing intake charge velocity. And that miniscule difference in intake velocity is what gives rotary the narrow edge. A transverse rotary is even better as it dumps the incoming charge between the crank webs, just behind the cylinder transfers.  Combine all that with the knowledge that a rotary valve can be independent of piston position, and therefore successfully manage backflow and low-end issues, and you have a very spicy meatball.  Alas, the ship has sailed on all of my current bikes, they will all be reed valves. But now I'm thinking that for future efforts, I'll try to build a rotary bike. 

         I can find very little info on this motor, lots of pictures on complete bikes racing, but very little on the engine itself, or its 250cc brother. I made a graph to illustrate what an efficient powerplant the RSA is. Basically, the total power of the motor, divided by the capacity. As an example, the Yamaha R1 is rated at 172hp. If it were as efficient as the RSA, it would have 280 MORE hp. I realize the logic is kinda flimsy and my numbers are not all official, this graph is more a visual aide than anything. Not pictured: as it didn't fit on the graph is the pokey Harley Sportster 883 with a rating of 19.2. 

   

          In other news, I made another batch of Tomos/Polini/Daelim type intakes and tree'd them up. As I'm writing this, the wax is being cooked out of the mold in my oven. Probably this week I'll cast the mold and see if things are improving. I altered my mold design based on some suggestions from fellow engine nerd / metal caster Graham. Elsewhere, I used a bore bar to enlarge the small end on my Vespa PK crankshaft to fit the new piston for my smallframe racer. I originally bought a 20mm reamer to do this, but after setting everything up, the Adamantium or whatever the con-rod is made of actually dulled the blades on the reamer. The new piston is about 8mm wider than the old one, and should produce a big improvement in capacity.