The following tech tips are mainly from my experience. Then you might ask "What is your experience?"
(If you don't care about my boring life and want to get on with the tech tips, click here)
Well, it all started when I was 3. I guess you don't want to here all that, so I will give you the brief version.
It all started when I was 3, my dad was an auto mechanic and a graduate of an aviation technology school and pilot. I hung around with him a lot and some of his knowledge rubbed off on me. Sometimes not as much or as fast as he would have liked. He progressed on to machinist and on to tool and die maker. His claim to fame or lack of, was that he worked on the first jet pilot helmet that attached to a suit and worked on the prototype of the first recirculatory back pack for the moon probe.
As I grew up (or lack of growing up) my interests were in mechanical things. I watched my dad work on his personal projects and handed him wrenches. He wouldn't let me help as he said I was too little. That's strange because I don't ever remember being little. My first project was my own design of a pulse jet engine. I would sneak into my dads garage (when he was not home) and work on it. I got it to make one "Pop" at a time in the correct direction but never could get it to continue on. I then fell in love with this beautiful creature in a magazine. It was called a "45 Harley Davidson". Every chance I got I would touch one and drool all over it. I approached my dad about getting one and always got this "Too little" thing. Finally, Dad agreed to let me buy a motor scooter with money I made at summer jobs. The only one I could afford was a used homemade scooter. The owner said he hopped it up. My reading gave me a little enough knowledge to be dangerous so I asked what he had done to it. he said he "bored it out". I bought the "Hopped up scooter for $20." (My life savings). I soon found that "bored out" to him meant that the 14mm plug hole was bored out to use an 18mm spark plug. My first engineering project was to change the belt drive to a chain drive. But then I had to design a clutch. I didn't have any material for a clutch lining but did find some blocks of hard rubber. It worked great, two or three times but soon I discovered spin welding. Did you know you could spin weld hard rubber? Proto-type #2 was I went to a junk yard and bought a Indian motorcycle gearbox and mounted it over the rear wheel. With bicycle chains and sprockets I finally had a 3 speed motor scooter. I sold that and every thing I had that would sell and scratched up $50. to buy a disabled Indian motorcycle that had been setting outside of an air force base gate. A piece was missing out of the rear wheel and Dad made one on his lathe. I got the engine running before he finished the part so it was ready to go when he finished. It was a 1938 Indian Chief 74 cubic inch and sounded like a 1000 HP. I was so happy and excited I thought I was going to explode. I was afraid of it so I asked Dad to try it out. he road up the road and back and said it was OK and told me to ride it. I wasn't old enough to have a drivers license yet even though I drove my dad and mom to work for two years in their car.
With all the tuning I could do, 18 seconds in a quarter mile was the best the Indian would do. So, my first hop-up was to hand grind the base of the cams so as to increase lift and duration. It would now do the quarter in 17 sec. which was a disappointment to me but I didn't learn until later in years what else I should have done. As a kid, I loved to take them apart. and at times I even got some of them back together. I also loved to read about them and reading sometimes can get you into trouble. And occasionally "Out of trouble". After school I moved to Panama City Florida to work in a Triumph and Cushman dealer.
Started racing professional on TT tracks in Alabama and after a two year term in Germany in the Army I returned to Jax FL and worked in different motorcycle shops, BSA, H-D, NSU, Matchless and Honda. By now I was racing professional flat tracks in N.C., S.C., Georgia, Alabama and Florida. Among other racers I was considered too conservative and at 210 lb and 6ft 5in, too big to get out front. At that time The AMA had a point system of three points for first, two for a second and one for a third place. Heats and Semifinals counted, 20 points were needed to advance form Novice class to Amateur. and an additional 40 points to advance to Expert. The bikes were all classed the same, 500cc for overhead valves (BSA, Triumph mainly) and 750cc for sidevalve engines (H-D) (by then most of the Indian 45s were gone. I did OK though. At 8 race meets I made 20 points to advance to Amateur class. Some friends started road racing so I bought a little 250cc Honda and set it up with a home made fairing and my own hop-up. I took it to my first race. (Daytona) and a time trial netted me a 4th fastest of about 150 bikes. No, that didn't net me a first row start. It was to establish a pecking order for the three classes running. DUH! Because I was a AMA pro dirt tracker I learned (the hard way) to listen at the riders meeting. This netted me a first place into the first turn and a first place for three laps. Pretty good for first race of a conservative rider of 210 lb on a home hop-up on a 250cc bike Huh? That soon ended when I fell off coming off of the grandstand straight onto the infield. Over 85 MPH get-off netted me 17 stitches in my left knee. A week or so later an FIM race was scheduled there and I was on crutches but planned to come down to watch the main race Sunday. On Sat. I got a call from a friend at the track asking if I still had my AMA license. Because the owner of a Manx Norton that was # 1 in Canada showed up but his rider didn't and he wanted an AMA rider to ride it. That is like a local stockcar driver getting a call to come drive an Indy car. I tried every way I could to get my knee bent to get it on a bike but no way so I had to say NO to the opportunity of a life time. Just a chance to ride one of the top world class bikes against the top riders in the world including Mike Hailwood would have been something to tell your grandchildren. But that just wasn't meant to be.
Two more road races netted two more "get offs". Hmmmm! I think I see the writing on the wall. I don't think I have enough hide left on me to learn how to get good at this road racing. It wasn't until years later I figured out why I could be a smooth conservative rider on dirt and a fast but wild rider on pavement. Surprisingly it came from ground school for a commercial pilots license. It had to do with my method of judgment of speed.
I went back to just dirt tracks, but as an amateur I was middle of the pack now and had to work like hell just to gain inches on other riders. It was strangely serene and smooth to be in the middle of a pack of bikes all sliding through a turn. The sound was deafening and sliding a motorcycle with no brakes only inches from other bikes on all sides of you at 70 and 80 MPH may sound crazy to some but for those who have done it, there is nothing in the world that compares to it.
I know, you are asking, "What in the world has this got to do with a tech tip?" The answer, Nothing, other than to show you some of my background and how I approach a tech problem. Even though I listen to "Experts" on how something works, I never assume they are correct. Yes, I have wasted a lot of time reinventing the wheel. But, I have also found some flaws in the "Experts" theories. Like, ask a bunch of experts what happens if you change from a centered piston pin to an offset piston pin. You will get a verity of answers.
Here is what you did.
You changed TDC
You changed BDC more than changed TDC
You made the up stroke a different number of degrees than the down stroke
You changed the velocity of the piston between the up stroke and the down stroke.
You made it so if you change the length of the rod you changed the stroke
You made the engine out of balance
You changed the power curve of the engine
You changed compression ratio
You changed the volumetric efficiency
You changed piston skirt and cylinder load
You increased the load on the rod, bearings and crank
I got married and had a child and made a startling discovery. Auto mechanics make more money than motorcycle mechanics (at least back then they did). I tried several times to get into an auto shop and was turned down as soon as they said, "I see you worked in several motorcycle shops but what car shops have you worked in?" Hmmmmm! must be something different about car engines???? Then a friend told me about an opening at a Jaguar dealer. I filled out the application but got to a question that said, "What car shops have you worked in?" Hmmmmm! that sounded familiar. But, there was a large blank space and I knew a Jag was a dual overhead cam hemi so I just told them why a DOHC engine was better than a OHV engine. The service manager was a automotive engineer and use to teach Jag school. And he was a famous hydroplane boat builder and racer. I got the job over several auto mechanics. From then on I worked for MG, Triumph, Jaguar, Alfa, Lotus, A-H, Jenson, Sunbeam and had my own shop for a short time. I was also a service writer, service manager and started teaching in a commercial mechanics school. During this time I got my commercial pilots license and even bought a small plane. I also tried my hand at tool and die making in a shop that made some dies for Ford, Chevy and Chrysler. I did Ok but couldn't handle the pressure of the long hours of concentration required to learn the trade. Of all the types of places I worked I think they were the finest group I ever worked around. I then took a job in Nashville TN as a Tech rep with WorldParts Corp. By the grace of old friends I was still able to get in on some upgrade factory training on several cars and took the tests for ASE as Master in automotive plus the L-1 certification and got the SAE associate membership. We answered a hot line for mechanics and traveled the whole US giving seminars on Import car repair. And for a while we were loaned to JC Penney to train their mechanics on strut installation nation wide. After 6 years I left WP and worked for a new propane carburetion company at Doug Nash Engineering, trying to get a new design carburetor from proto type to a production model. I then worked for Nashville Auto Diesel College, teaching gasoline engine theory and rebuild. I then took a job as Product Information Manager for the marketing division of Manley Valves and Badger Pistons. I then worked as a quality control inspector for a local VW dealer and returned to WorldParts / Beck Arnley for another 9 years. I have attended training classes on various fuel injection systems, electronics of several types of cars, trained on several brands of propane carburetion systems and trained on Clayton dyno testing.
Now that I have put you to sleep, You can get over to the real tech tips via this link. GO