This is the book everyone wanting to learn about getting more performance  should read. In this book they use a Yamaha SR 500 as a example , parallels with the Savage engine quite well. All the theory , all the math , it's a fantastic book , has been in print for many many years and is still relevant today. The teacher I had used this book in his engine performance class Dema Elgin of Elgin Performance Cams. You can find it new or used online.

Four Stroke Performance Tuning by A. Graham Bell

It's worth every penny !

Here ya go:
https://www.scribd.com/document/79009859/Four-Stroke-Performance-Tuning-3rd-E...

Ruttley .Yes heard of this book in earlier posts ,will check it out.thanks!

hotrod wrote on 04/04/17 at 13:46:37:

Another great book is, Design And Tuning Of Competition Engines, by Philip Smith. Mine is old, like 1966.  It's a surprise to see that not much has changed over the years. Those old dudes were smart.

In 1966 the ICE was already over 75 years old. Of course they knew a lot about engines. Look at the advancements through the 1940's and 50's alone. Before the jet era Pratt and Whitney, Allison and Rolls Royce built the most advanced engines the word had ever seen. Race car engines were making over 100hp/liter. By the 1960's the ICE was well known and established technology. It certainly wasn't the dark ages.

Yes, the basic formula of suck-squeeze-bang-blow hasn't changed in 50 years, but almost everything about the ICE has. When that book was written points and condensers buried inside of a distributor and mechanical fuel injection were state of the art. Few could ever imagine computer controlled engine management that has given us variable valve timing, direct ignition, electronic fuel injection, HCCI...we can go on for pages.

Ruttly wrote on 04/04/17 at 20:50:48:


And that is exactly why I ride!

Most of these books talk about intake plenums and header collectors. That's something unknown to a thumper but the rest of the book usually applies.

I live about 45  seconds from a main road. In that 45 seconds, while I leave the neighborhood in 2nd gear, my whole attitude changes. It can be the worst day ever but in that first 45 seconds, my whole world changes. The bike and I are warming up together, so to speak.

For total overall performance the SR500 is a better engine , but I already have one , so I needed another project. RYCA tracker original plan was find the donor bike ,put nice exhaust on it and rejet stock carb and call it done.
But oh no , two things changed all that , first is I found this forum and all goodies to be had from here and a great membership complete with technical support and second was I found my donor engine leaking oil between the two main cases. Darn the bad luck now I had to tear down a engine with only 809 miles on it. Upside of that was I get to build the engine.
Finding that this engine has its draw backs , a simply horrible exhaust port and a crankshaft/flywheel/rotor that is incredibly heavy and flimsy clutch basket , amongst some other issues. But it has two outstanding attributes it's a big 650 single with a happy button.
I will spare you all the long a$$ list of engine mods , but it is much improved over a stocker as far as power , now we will find out if it will stand up to the test of time !