Friday, August 6, 2010

July 7, 2010
I have been monitoring the max speed that I get after about a 1/4th mile hill of 30 feet. In the past 3 weeks I have been testing a lot of variables with expansion chamber length, transmission settings and carburetion.

My first tests showed that I couldn't get the engine to come up on the pipe. I lengthened it from about 25 to 29 inches and it would come up on the pipe strong but even with 16.5 grams in the variator I could feel the engine get stronger from about 37 mph until it flattened out at 47.7mph. My pipe was getting cobbled up so I made a new pipe with a 32" length. The pipe comes on lower now and would pull to about 46. The only way that I know I am optimum is when I go past that point.

I knew my pipe is really too long for max speed now and plan on cutting my new pipe down some perhaps an inch.

I also am going to put in a stiffer contra spring and rebuild my variator with some decent weights. I may want more rpm with acceleration and want to make sure that the internal friction of the variator doesn't overcome the weights.

No matter which setup I used I encountered almost the same top speed. I calculated the port time area and it was decent for almost 13000 rpm. To me that pointed to the intake system. The reeds and carb.

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