View Full Version : 2 Stroke engine performance resources. Books, and other things.

Billy Golightly
03-16-2007, 10:58 PM
I'll try and get the ball rolling in here with a list of books I currently own on 2 Stroke engines, and 2 stroke engine performance tuning. I started reading these about a year ago now and I've learned so much in just the short time already its mind boggling. Anyone interested in doing their own engine porting, or taking the time to learn the intimate secrets of 2 stroke engines should take the time and read each of these books.

Two Stroke Tuners Handbook by Gordon Jennings: This is in my opinion, hands down THE BIBLE of 2 stroke engine tuning. Written in the early 1970's by Cycle magazine writer and engine tuner extrordinare you can learn more about a 2 stroke engine from this book then you can imagine. I have read it cover to cover 7 times so far and I STILL pickup something new that he mentions every time. Important topics covered are Port/time area formulas and how to calculate them, cylinder head design and improvement, crank case volume, crankcase pressure, transfer port angles and heights, rotary valves, piston port engines, exhaust and intake resonance, efficiency, complete with formulas. Even though this is just the tip of the iceberg for the treasure trove of information this book holds it is very very easy for a person to read and understand. By following the information in this book you can make even the slowest slug of an engine run like it was designed for a motoGP track. Even if you only have elementary understanding of the 2 stroke engine and how it works, you can jump right in with this book and have everything laid out for you in easy to understand and comprehend terms. Highly recommended as the first book to read on the subject! ISBN: 0-912656-41-7

Two Stroke performance tuning by A. Graham Bell: This is a great follow up to Jenning's book. Its a little bit more technical, and novices of the 2 stroke engine may have a hard time comprehending some of the concepts but sarge on through the book and you will learn a great many things ranging from Exhaust pipe formulas, port maps and layouts, power valves, extensive information on reed valves and operation, intake stuffers and their purpose, tips and tricks for lubrication and cooling to give your engine better life, and a more up to date look at carburation and ignition systems then Jennings book has. Its info ranges from Dirtbikes, to MotoGP machines, to carts, to trials bikes. ISBN: 1-85960-619-9

Two Stroke Tuning by Roy Bacon: This book has a lot of info already well covered by the two previously mentioned books, but it also has a few things that they don't cover well. One is crankshaft splitting and rebuilding in detail with several diagrams, and what to do if you happen to press it together slightly off. The other is information on porting, and improving your stock reed cage and intake tract. Grahams book touches on this briefly, and the info in this book adds to it. The back of the book has some pretty good info on how to read Lectron carb metering rods, and how to tune them. That info is hard to come by. Its also got a pretty interesting index of specifications for many motorcycles and dirtbikes. Information ranging from stock timing, carb settings, clearences, and wear tolerances. Not a very good stand alone but a great additional resource. ISBN: 0-8518-4039-6

Two stroke Exhaust Systems by Roy Bacon: This is a very small book that is almost like a pamphlet but still has some good info. It ranges from the different type of 2 stroke exhaust pipes which are a plain pipe, pipe and megaphone, pipe and expansion box, and the current day resonant pipe. You'll get educated on things like negative and positive pressure waves, exhaust temperature varying pipe efficiency, pipe construction, mounting, and maintenance. No ISBN. Printed by Lodgemark Press.

The High Performance Two-Stroke Engine by John C. Dixon: This book is probably the most detailed and hardcore book out of the list. It is also consequently the most mathematically complex out of the books listed here also. There are others (Such as Gordon P. Blair's Design and Simulation of two stroke engines) that are more technical, but I have not read them yet. Its got formulas for everything and even ventures into the very serious realm of calculating and anticipating the fluid/air dynamics inside of the engine as they are happening. There is an entire chapter on head dome designs and how they should vary dpending on the types of fuels being burnt, and what the engines specific use will be. A nifty chart with different types of fuels or additives to use in the engine for different applications IE anti detonation additives for a gasoline base, methanol 10%, acetone 10%, benzol. Easier starting, Propylene oxide 5%. To sum this book up, its got every topic all the previous books mentioned in the most hardcore, geeky way possible. There are calculations, and limits for every single part of the 2 stroke engine and this book will explain them all to you with a performance first attitude. Not for the faint of heart when it comes to 2 stroke engines!ISBN: 1-84425-045-8

Two stroke high performance engine design and tuning by Cesare Bossaglia: This book is rare, and almost not worth mentioning because of that. First printed in 1968, although not that much older then Jennings book this one just “feels” like a lot of the info is outdated. However, the best part about this book are the numerous obscure designs and ideas people had for 2 strokes back when it was at the start of its hey-day. Even though this book is old, it is almost an engineers reference. It goes over a few topics not covered in other books such as bore and stroke proportions, balancing, theoretical analysis including the forces exerted onto engine components like the crankshaft, piston, connecting rod, and wristpin and how increasing an engines power levels effects the forces applied to these parts. A large portion of the book is focused on the larger industrial type 2 stroke engines, although there is a lot of info about smaller motorcycle based engines. Tons and tons of pictures and illustrations, probably more then all the other books put together. I've read this book once, and some of it is difficult to understand because of the translation from Cesare's native language and also because some of the things its talking about have absolutely no place in todays engines and its difficult to understand the usage of such ideas and theories without being able to imagine it. Read this book when your ready to really think outside the box on your next engine build, you'll have so many crazy ideas you wont even know where to start. No ISBN: Lodgemark Press.

I'm still constantly looking for books relating to this subject I've not yet read. The 2 main ones I'm missing out on right now is Gordon P. Blair's Design and Simulation of the two stroke, and MIT Professor Heywood's book. I will obtain these in time, study them, and then add a review of their content to this thread. If anyone else have a book not mentioned here and has throughly read it, feel free to post your overview and thoughts of what you learned from it.

Billy Golightly
03-16-2007, 11:23 PM
Web links for more information, resources, and applications:

Advanced Porting Basics: http://www.minimotoclub.co.uk/vb/showthread.php?t=9923

Hot Rod Magazine connecting rod choices: http://www.hotrod.com/techarticles/choosing_the_right_connecting_rods/

Helmholtz Resonance. Formula for designing a tuned length intake tract:

Kinesethic Energy Injector. A device developed by Eric Gorr in the early 1980s based on a helmholtz resonator: http://www.google.com/patents?vid=USPAT4457267&id=YvJ1AAAAEBAJ&dq=Eric+Gorr

MaxxTraxx USA Tuned Pipes:

HPT Sport Tuned Pipes:

Vins Bike Page, formally 2strokes.html:

Java Pipe Tuned pipe designer:

MOTA 2 Stroke performance software:

Two Stroke Racing (TSR) performance software:

Optimum Intake Runner Prediction:

03-17-2007, 08:02 AM
Very Cool Stuff...Thanks Billy

Billy Golightly
11-05-2007, 06:33 PM
bump for those that might have missed this.

11-08-2007, 10:32 PM
Hey Billy have you heard of MacDizzy? At one time you could access it for free. I was wondering if would be worth the money to join their forum.:wondering

Billy Golightly
11-08-2007, 10:36 PM
I don't know, I haven't ever been on it before. I would actually spend some serious time at PlanetSand in their 2 stroke forums first. I don't know whats at MacDizzy's forums but the PS ones have some extremely technical and insightful conversation a lot of the time and its all free.

11-08-2007, 11:38 PM
Two Stroke performance tuning by A. Graham Bell:
Awesome book! I think this book is the best book for 2 stroke engine builders and tuners to start out with. I think with all the pics and diagrams, you get a good understanding of the 2 stroke engine and well worth the $35 price.

Two Stroke Tuners Handbook by Gordon Jennings:
Good book, not as good as Graham Bell though. You can also download the pdf version of it...somewhere. I have it if you cant find it.

Gordon P. Blair's Design and Simulation of the two stroke:
Dont waste your money. It is $100, and the book mostly goes along with his software and teaches you how to use his 2 stroke software. Most of the info in this book is not used in the real world of 2 stroke engine building. Although there are a few interesting chapters, most of the book is over everyones head.

Mac Dizzy was one of the pioneers in 2 stroke engines on the internet. His site use to or still does contain tons of links and 2 stroke info.

TSR Software... It is the best for a reason. Measure every aspect of your engine and it will give you a horsepower rating.... Then change the numbers around to figure out what mods will do what. I bought mine probably 8 years ago for like $1000, now its like $500 and you get more programs and they are updated.

11-08-2007, 11:49 PM
bump for those that might have missed this.

make it a sticky? this stuff is interesting for sure.

11-09-2007, 12:12 AM
Hey Billy have you heard of MacDizzy? At one time you could access it for free. I was wondering if would be worth the money to join their forum.:wondering

I've heard that it isn't worth joining anymore, but that's just what I heard. There's some good stuff for free in the thread spread,


I've heard dynotech has a TON of information you can get for 20 bucks a year, mostly sled stuff though.


10-11-2009, 08:29 PM
Mac Dizzy


Billy Golightly
10-11-2009, 09:36 PM
I've got a macdizzy membership. It could be argued its worth it for the ability to back and read everything in the archives (which does date back pretty far) but there isn't hardly anything in the line of new material. The $25 for planetsand.com is a better investment IMO.

Dr. Kit
12-10-2009, 01:19 PM
Concerning 2-Stroke tuning ressources, it could be interesting also to look at the pulsjet side...

I think that highly-tuned 2-Stroke engines and pulsejets are very near, in a certain sense (effect of expansion chamber on intake = use of the synchronization of the acoustic waves in pulsejet intake)

Maybe Dr. Schnurle also worked on pulsejets!

Two PDF brochures :




12-13-2009, 12:02 AM
thanks Billy! deff will come in handy

12-14-2009, 07:28 AM
Gordon Jennings Archive


Billy Golightly
12-14-2009, 11:47 AM
Dr. Kit, welcome to the forum. Never knew or read about pulse jet engines before. Going through the first .pdf right now, very interesting stuff! Thank you for the contribution.

Dr. Kit
12-15-2009, 05:14 PM
Thanks. Yes, pulsejets are great.

Here is a link where you can see an animated GIF showing 2 Stroke engine in a dynamic way (bottom of page) :


The effect of the negative shock wave from the expansion chamber, extracting more gaz directly by the transfert ports and the carb, is very visible in this GIF. It's exactly like in a pulsejet : the violent depression wave following the burnt gasses has the capacity of admiting fresh gases, without the action of any mobile element like a piston. It's a way of using "free energy" from the exhaust gasses which would have been lost, to obtain a certain degree of "overfeeding". It can be seen like a kind of "sonic supercharger". And so the filling of the cylinder is better. And I think this is the secret of the incredible power of modern reed valve 2 Stroke engines. In fact, 2 Stroke engine is a kind of pulsejet!

Here are two Youtube links. The first is a mega-tuned Kreidler 50cc, the second is a small pulsejet. The sounds are from the same family...



Hum, I hope this kind of post is okay in the "Mad Scientist Lair"!...

Billy Golightly, I readt your first post, concerning two stroke tuning ressources. I had readt yet the book "2 Stoke performance tuning" by Graham Bell, and found it very interesting. But, after reading your post, I readt (in fact I read it now) "2 Stroke tuner's hand book" by Gordon Jenning. And you are right : this book is really the bible, it is very very interesting, ALL the problems are explained, or at less, seen, by the autor. And this book is very clear, simple and of high level at the same time, and very nice to read, also, nice style.
I think I'll spend some time reading the others books, after... (Okay, maybe I'm a "2-Stroke nerd")

tecate 250rr
12-18-2009, 06:55 PM
Thanx you guys for this thread and all the contributuions .I am a knowledgeable mechanic and this stuff is just amazing i wish i could absorb more faster , thanx again

12-18-2009, 09:44 PM
Two Stroke Performance Tuning by A. Graham Bell


Dr. Kit
12-23-2009, 04:37 PM
Another little contribution in the pure mad scientist style, about “Kadenacy effect”…

If I undersdand well (wich is not very sure…), the Cadenacy effect is a “storage” of energy from the previous stroke (cycle), under the form of pressure differential, to use it in the following stroke. This pressure differential is created in the crankcase by the negative wave generated by the diverging part of the expansion chamber. This phenomenon exists particularly in pulsejets and in two stoke-expansion chamber engines

Some links :



(“a kind of reciprocating air pump without any moving parts!”)


And I think that Gordons Jennings, in fact, speaks about this phenomenon, page 91 in “Two Stroke Tuner’s Handbook” :