IBRARY’s comprehensive
booklet on obtaining the best speed & performance from your classic Triumph “B” Range 1963-* 650cc or 750cc unit-construction twin, including the single-carburetor 6T Thunderbird & Saint, TR6, TR65 and TR7 Tiger and Trophy, and twin carburetor T120, T120V and T140 Bonneville. Your “obsolete” Triumph twin is capable of surprising speed & power, without loss of reliability. Over 35 years of research and experience has gone into this booklet. It’s the most modern and complete do-it-yourself
literature you can buy to get the most from your Triumph. Before making any decisions about modifying your motor, get the best help available, and do it right the first time.
This booklet is not
a repair manual, but goes far beyond into fine tuning, improvements and
modernization. Use it with your service manual for best results. Not an
expert mechanic? You’ll still find many improvements you can make yourself
with common hand tools. I identify parts and procedures that, in my opinion, have little or no value, or are not cost-effective - avoid these and save yourself time and money.
Perhaps you're preparing a vintage road racer or flat-track machine for AHRMA, and are required to use many stock parts by class rules. How to give your bike an invisible competitive advantage? Making an “old-school” drag racer? Which old time speed equipment will help? You don’t just want this booklet - you need it.
Don’t rely on a shop, even one with a proven history, to prepare your engine to out-perform the owner’s personal entry or those of their premiere (famous) customers. Do they just use the same cams, carburetors, pistons, valve sizes, transmission ratios, pipe lengths & flywheel weight they’ve been using for the last 30 years? Why? With this information you can become part of the design team, rather than just the sponsoring rider.
British shop owners, tuners, engine builders and mechanics: your customers can improve performance without changing original appearance. Many of the modifications described in detail in this booklet will be completely new and attractive to your performance-minded customers, and add many billing hours to your service department.
In addition to proven modifications, I also include many new ideas, potential adaptation of concepts known to produce results in other engines, etc. that in my opinion may provide the innovator and craftsman with new methods of gaining a competitive advantage (although these carry the usual risks of cost vs. benefit, development time, etc.).
I guarantee that you’ll find well-tested and effective information in this booklet you’ve never seen before, and that will help you plan and complete your project.
Consider this: if this booklet saves you from making even a single mistake or bad purchase, or gives you one new idea, doesn’t that make this purchase worth while? The price is a small fraction of what you will invest in the motor - plan more intelligently, and get better results.
Please note: this booklet is only directly relevant to the “pre-unit” (1946-62 3T, 5T, 6T, T100, T110, T120 etc. 350cc, 500cc & 650cc) engines in a general (not specific) manner, although the information and comments are applicable.
This booklet does not address the smaller 1957-74 “C” range unit engines such as the T21, 3TA & T90 350cc and 5TA, T100A, T100C, T100R, T100SS, T100T, TR5A & TR5T 500cc, sorry. I have some general data here: .
Owners of similar British pushrod OHV parallel twins such as the BSA A7 & A50 500, A10 & A65 650 & A70 750; Norton 500, 600, 650, 750 & 850; Matchless 650; and Royal Enfield 500, 700, & 750 will find much of the theory, design concepts and information applicable to their machines, although obviously the specific instructions and dimensions will not apply. I also have some data posted for three of these; BSA unit ; BSA pre-unit ; Norton .
Stapled in paperback to reduce printing cost, it includes the following chapters, some with black & white illustrations, diagrams and charts:
Bore & stroke chart; gives engine size for all bore oversizes and stroker flywheels.
Aftermarket speed equipment; the only detailed guide
to aftermarket speed equipment both
current and obsolete, including big-bore
cylinders, with a table of bore size, material,
required modification for use and illustrations.
Stroking; details on installing long-stroke
crankshafts, adapting the Norton Atlas or Commando
89mm crankshaft, selecting components, where clearancing is necessary, calculating skirt lengths,
piston compression distances, much more.
Building a short-stroke 500cc motor; for vintage racing.
Alternate “offset” firing order; explores 76° & 90° crankshafts.
Crankshaft inertia; what it is, how it affects power, when more weight is helpful.
Engine balancing; how to be sure the work is done successfully.
Crankcase breathing; how it functions, making improvements.
Long rod vs. short rod; which is used when & why, examines the effects of rod ratio in detail.
Oil system; explores function, variations.
Port efficiency; examines size, shape, down-draft angle, improving flow.
Combustion chamber; explores quench & squish, “bath-tub” shape, head milling for compression
with a table of distance vs. ratio change.
Dual plugs; when they are an advantage, tuning changes needed.
Porting; improving port efficiency by changing shape.
Intake port tuned length; theory and practice, pre-calculated tables with length vs. RPM, etc.
Exhaust system design; megaphone vs. straight pipe, tuned length, backpressure, etc.
Tappet radius; what is it, what effect does it have, what choices are available.
Rocker arm geometry; which parts are affected, when & how to analyze it for errors, make
corrections, determine proper pushrod length, reduce wear & breakage, and improve efficiency.
Lightened rocker arms: what does this do, and why; with dimensions and diagrams of how to
remove metal from non-critical areas to reduce weight without compromising strength.
Cam choices; listing manufacturers, part numbers, duration, overlap, lobe center angle, lift etc. for more than
30 high-performance cams, with comments on selection.
Cam phasing; very detailed description of how the power curve of an engine can be altered by
changing the positions of the cam gears, effects of changing the lobe separation angle,
advancing and retarding the cams, with tables of lobe vs. tooth positions, etc.
Transmission ratio chart; gives individual gear ratio, engine RPM lost on each shift, as well as
tooth counts of all factory and aftermarket (Quaife, Triple Cycles) gear-sets for the 4-speed
and 5-speed transmissions, using gears from more than one set to make your own ratios,
how to pick the best ratio for your engine and racing format, which factors affect choices.
Installing a 5-speed; in unit or pre-unit 4-speed transmission cases.
“Vintage” and “Production” Classes at Bonneville; how the rules apply to your project,
advantages, compensating for high altitude.
Most dimensions are given in fractional inches, decimal inches and metric for the convenience of tuners in all languages.
Please note: this is not a “coffee table book” of vintages racers, it is a research tool for those who seriously want to improve their Triumph engines. It does not include information on Amal Concentric, Amal Monobloc, or Mikuni carburetors, which I cover individually in separate booklets; see the links below. It is not a repair manual. I assume that you either are, or have a good working relationship with, an experienced mechanic. If your bike won’t start, your float bowl leaks, the spark plugs foul, &c. my booklet will not help you. It does not contain information on tune-ups, or explain how to adjust, disassemble or rebuild the engine. If you do not already have this information do not buy this booklet. If you’re pleased with how your engine runs now, this booklet is not going to be of much use, although you might find it interesting.
The proposed price of this booklet is $29.95 + postage. The draft version is over 90,000 words as of March 2008, and may be substantially larger when completed. It is not available yet. Do not order, all payments will be refunded. Click here to receive notification when this booklet is available: .
