Building a Vintage Triumph 500cc Road Racer

You don't have to go to one of the Japanese makes to build a budget 500cc or 350cc Vintage Road Racer. A 60's period unit construction Triumph offers an inexpensive and competitive alternative in the VRRA/USCRA Period 1 class and AHRMA Premier and Sportsman classes.

This paper is an account of my experiences building and racing Triumphs over the last ten years. A number of companies are mentioned in the text and this is intended as a sample of the many companies that exist to supply the Vintage Racing movement. Mentioning a company does not imply personal experience of that company or an endorsement of their products (unless this is specifically mentioned). Likewise, there are many ideas, opinions and methods of performance improvement. I am covering those I have used or seen used, and there are many others not mentioned here. I take full responsibility for any inaccuracies and would be pleased to answer any questions or provide further info - please e-mail me at: m4101ep@yahoo.com

 Topics discussed are:

1. Frame
2. Front Forks
3. Front Brake
4. Rear Brake
5. Rims
6. Tires
7. Suspension units
8. Other items
9. Electrics UPDATED
10. Engine
11. Exhaust System
12. Carburetors
13. Clutch and Primary Drive UPDATED
14. Gearbox
15. Gearing
16. Bibliography
17. Suppliers UPDATED

1. FRAME

 There are at least three choices of frame - Standard Triumph; TR5T OIF (Oil in Frame); After Market

• Standard frame
• Use a frame from 1967 or later
• These have an revised head angle (altered from 65 deg. to 62 deg.) which improves high speed stability
• Earlier frames have a small top tube and larger second tube
• Later frames have a larger top tube and a smaller second tube
• Later frames have outrigger plates are welded to the sub-frame and bolted to each end of the swinging arm pivot spindle. This is a significant mod for improving handling as it reduces twisting of the swing arm mounting lug with the resultant wobbly handing when cornering under power.
• Wheel base (standard) is 53.5"
• Comparatively cheap and available
• Designed to allow work to be done on the engine without removal from the frame
• TR5T
• Basically a BSA B25/50 frame but modified and strengthened to take the Triumph engine.
• Although Triumph only produced the model for two model years (1973/4), there are two conditions of frame. Both are good but the later condition has more bracing around the frame loops in the swing arm area and so should be stiffer. I believe some cracking in this area was experienced with the earlier frame and resulted in these modifications.
• It is possible to modify the standard B25/B50 frame to take the Triumph engine. New brackets are needed and care with the chain line.
• The frame is stiff, handles very well indeed, and the wheels remain in line because chain adjustment is done by cams at the end of the swing arm pivot bolt.
• Pros
• No separate oil tank
• Seems lighter overall than the standard Triumph frame (oil tank, all welded construction)
• Good handling
• Cons
• Limited oil capacity (2.2 liters)
• If oil contaminated (e.g. after an engine mishap) then it is a laborious operation to clean out the frame tubes completely (oil filter strongly recommended)
• Limited clearance from the second frame tube and the top of the engine
• Triumph recognized this and changed the four inner head bolts to studs and long nuts. Even with this setup, it is very difficult to lift the head with the engine in the frame and put the rocker boxes back on. Special rocker boxes with enlarged bolt holes are also necessary.
• If the standard head bolt set up is used, the rocker boxes and head can be removed with a lot of difficulty (the engine mounting bolts have to be loosened), but it is impossible to reassemble.
• Wheel base (standard) 54"
• Head angle 63 deg.
• Limited availability (not so many around as the standard Triumph frame)
• Comparatively low cost
• After Market Frames (e.g. Rickman, Seeley etc)
• These are likely to be a better overall package than the Triumph frames as they were designed originally for racing
• Limited availability (few made and mostly in use)
• Likely to be costly

2. FRONT FORKS

 There are three choices (at least) of front forks: Standard Triumph; BSA/Triumph '71 on; Ceriani type

• Standard Triumph
• Should only be considered if the standard Triumph frame is being used
• Use a set from a model as late as possible
• Modifications to improve action and handling:
• Shorten stanchion tube by 1" to improve high speed stability (results in slight heaviness at low speed ) or place 1" spacer between top bush and tubular damping slider
• Spring length may need to be shortened but it is best start with the standard length and experiment if necessary
• Fill in the two small holes at lower end of stanchion - this improves fork action
• Change the ball and cup steering head bearings to taper roller units (kit available from Triumph parts dealers)
• BSA/Triumph '71 on
• Aluminum triple clamps and sliders
• Standard fitting on the TR5T frame
• Can be fitted to the standard Triumph frame with bearing kit (care - use a longer triple clamp stem than that from a TR5T, as there will be insufficient threads for the bottom lock nut on the TR5T stem)
• Probably better forks than the stand Triumph, but not as good as the Ceriani and other similar types

• Ceriani type (e.g. Ceriani, Betor, Bombardier, Mariozzi etc)
• Best type of forks - strong triple clamps and stiffness
• Length can be adjusted by raising or lowering the stanchions in the triple clamps
• If altering fork length ensure that there is sufficient clearance for the wheel at full compression. It may be necessary to fit a restrictor spacer inside the fork.
• Can be fitted to standard frame but triple clamp stem may have to be changed to fit the smaller internal diameter Triumph head stock
• Taper roller bearing kit is preferred although the standard cup and ball will fit (I have used this latter setup with Ceriani forks on 500 and 650 Vintage Moto-X machines with standard Triumph frames)

3. FRONT BRAKE

 There are four choices (at least) of front brakes: Standard Triumph; BSA/Triumph '71 on; Suzuki; Expensive

• Standard Triumph 8" TLS
• Fits right in to the standard Triumph forks!
• It's heavy and 1.25" holes can be drilled in both sides of the hub (5 each side)
• Fairly efficient and profits from racing linings (e.g. Vintage Brake)
• Easily available and comparatively cheap
• BSA/Triumph '71 on Conical TLS
• Fits right in to the BSA/Triumph '71 on forks!
• Lighter than the earlier brake although still heavy
• Needs to be modified to increase efficiency
• Extend brake arms by 1" (suggest they be cut and the additional 1" added to the middle (make sure the welds are strong!) - this increases the leverage
• Use the heaviest duty brake cable you can find - this decreases sponginess

• Suzuki "Water Buffalo" double sided 2TLS
• Popular brake with Vintage Racers
• Looks good
• Heavy
• Should work well (I have no experience with this brake)

• Expensive
• This category includes Ceriani, Fontana, Oldani, Yamaha TZ
• These are all custom made for racing and therefore in short supply and expensive
• They all work very well indeed, providing the linings are good and they are adjusted properly
• Fontana and Ceriani are being remanufactured and are available (at a very high price)

4. REAR BRAKE

 Choice of rear brake depends on the swinging arm and what ranges of sprocket sizes are required. The following are hubs that I have used and there are many other types out there. Sprocket size limitations is an important consideration (see section on Gearing). Racing linings should be used if the rear brake is used hard.

• Standard Triumph rear hub
• Fits right in to the standard Triumph swing arm
• The brake drum is bolted to the hub and some sprocket sizes are cast as one piece with the brake drum, so that to change the sprocket size, the whole drum must be changed (unbolted from the hub) - e.g.
• 43 tooth - cast with drum (smallest size available)
• 46 tooth - detachable (e.g. not a one piece casting and the sprocket bolts to the drum)
• Can be fitted to the TR5T swing arm but needs a different internal spacer made up to fit the smaller diameter TR5T spindle and a shouldered spacer between the brake plate and drive side bearing (details on request)
• Five equally spaced 1" holes can be drilled in the hub at the mid diameter line.

 TR5T conical rear hub

• Fits right in to the standard TR5T swing arm
• Heavy but efficient
• 47 tooth is the smallest size sprocket that will fit the hub

 5. RIMS

 This is a question of personal taste, availability of good tires in the chosen rim size, and the rules (certain classes and organizations stipulate maximum rim width and maximum diameter).

• Steel rims are the cheapest and most available second hand
• Unflanged Alloy are widely available but often in 36 hole and not 40 hole needed for British hubs.
• Flanged Alloy has the period look!
• I use WM3 x 18 as there is a good range of tires in this size

 6. TIRES

 This is also a question of personal taste and experience with the various brands. Slicks are not allowed, and tires must be DOT approved (see rule books). Good vintage racing tires are available from a number of companies (including Dunlop, Metzelers, and Avon). Currently I am using Metzelers (Front 100/80 V 18 TL ME33 Comp K; Rear 120/80 B 18 62V TL ME 1 Comp K MBS) which give excellent grip and are good in the wet too. But, it seems that everyone has his or her own opinion as to which tyre is the best tyre!

• Use a good quality real rubber inner tube (e.g. AVON, Michelin) - no patches or imperfections
• Balance wheels with the tires mounted and pay special attention to wheel alignment - it's critical

7. REAR SUSPENSION

 Rear suspension is, to me, in the same category as tires. It's a very personal choice. There are many good units available (e.g. Works Performance, Progressive Suspension, Hagon, amongst many others). A lot of money can be spent on these items so be sure someone with practical experience on a similar machine to yours, a similar weight of machine and rider, and at a similar riding level advises you.

8. OTHER ITEMS

• Footrests
• If you are lucky, you can find NOS kits including the linkage for maintaining the correct direction of gear shift, as well as custom made brake levers pivoting as part of the footrest assembly. These should bolt straight on to the standard Triumph frame plates which bolt to the rear sub frame just to the rear of the swing arm pivot or may need a new hole drilled in the plate. You can also fabricate a suitable setup or modify a set from another machine (e.g. sets are available for Japanese machines).
• In the case of the TR5T frame, the swing arm pivot plates are extended rearward, and drilled to accept a NOS Triumph kit.
• Gas Tank
• More and more, reproductions of the factory racing items are becoming available (e.g. Vintage Fiberglass Racing Supplies)
• Standard tanks can be used (in the case of the TR5T, I have moved it backwards 2")
• Seat
• Although the standard set can be used, it is better to use a racing item as it gives better support.
• Often, vintage seats are homemade, and if you can manage fiberglass, foam and leather, or you have some handy friends, try it out. Otherwise try a specialist company (e.g. Vintage Fiberglass Racing Supplies)
• Fairing
• Many styles of fairing are available, including Triumph factory replicas from the mid 60's (Dave Quinn)
• Screens can be sourced from Gustafsson Plastics
• Oil Tank
• TR5T OIF
• As mentioned in the Section on frame choices, the TR5T frame has limited oil capacity and if difficult to clean thoroughly after any incidents causing oil contamination
• As an alternative to OIF, a 1-gallon tank can be made from aluminum (e.g. 0.040" 6061 Alloy). This fits in the triangular space between the seat and swing arm pivot (where the battery, electric's, and air cleaner used to be). Downside of this is that all the electric's (coil, battery etc) will have to be re located. See Section on Electrics for repositioning details.
• Standard Triumph frame
• The standard oil tank contains 3 liters, and may interfere with the carburetors. In the 60's, the Triumph factory made special tanks holding 1 gallon and extending the full width of the frame under the seat behind the vertical frame tube. These tanks were marketed by Tri-Cor in the mid 60's and so it may be possible to find one. I also heard of a company in Australia making the tanks, but I have no further information. If you fabricate one yourself, be careful to provide space for the rear wheel on full compression and allow for tire expansion at high speed.
• Oil filter
• I use a Norton style Oil Filter plumbed into the return oil line from the engine and before it goes to the rocker oil feed.
• It can be mounted under the swing arm pivot on the TR5T frame, using a steel strap attached to the swing arm pivot plates at each end. The detachable filter faces to the rear and thus can be easily changed without disturbing any other parts.
• On the standard Triumph frame I have mounted the filter on a small right-angled bracket bolted to the rear engine-mounting bracket. The detachable filter faces to the right and can be easily changed.
• Oil Cooler
• I find my engines run very hot and so I use oil coolers. If you need one, they should be mounted in the air stream as much as possible and, if angled back from the vertical, will be more efficient. Plumb the cooler into the return oil line from the engine, after the filter and before the feed to the rockers.

9. ELECTRICS

 I use BOYER Electronic Ignition on all my machines. I like the reliability and can "fit 'em and forget 'em". I have never (touch wood) experienced problems with these units, but have always been extremely careful when wiring to make quite sure it's as per the book. The other small item, which I prefer, is a cutout button that breaks the current from the alternator rather than grounding the low-tension circuit. Two reasons for this - one is that grounding out the low tension circuit could damage the Boyer, and secondly I would rather depend on a circuit break over a cutout button which depends on a ground which may or may not work. The cutout button from a TR5T works just fine, as would a regular switch.

• Standard Boyer ignition system
• Needs alternator (or total loss battery); coil; Boyer black box; Boyer timing trigger (replacement for the contact breaker); cutout switch; Zenor Diode; Rectifier; Capacitor.
• The Zenor Diode and Rectifier can be replaced by a small alloy clad unit (Tympanum), and these plus the capacitor can be replaced by one device (e.g. MitiMax). These, or similar, should available from Vintage Triumph spares dealers.
• Currently fitted to my standard Triumph framed machine, the Tympanum and capacitor are fitted to the bracket in front of the forks used to attach the front of the fairing. For the coil, I use a double 12 volt coil (from a 1973 Kawasaki 4 cyl. 900cc) and this, plus the Boyer Black Box, is fitted under the gas tank where the standard coils used to be. I use an alternator instead of a battery for reliability and less work at the track (not having to charge the battery all the time). The loss of power we put up with!
• Racing Alternator Boyer ignition system
• Needs alternator; coil; Boyer black box; Boyer timing trigger (replacement for the contact breaker); cutout switch.
• Although not strictly necessary, I use a very small 12-volt battery to ensure immediate starting (a switch is fitted to turn the battery off, immediately the motor fires up). Source - Radio Shack.
• Currently fitted to my TR5T machine, the Boyer black box is fitted behind the front number plate, as is the very small 12-volt battery. The coil, which is the Boyer item, is attached to the frame just in front of the gas tank, on the drive side frame plate behind the headstock.
• Coils with Boyer systems
• This is critical. The total resistance of the coils must not be less than 4.0 ohms. If one 12-volt double coil is used then this is the resistance of that coil. If two coils are used (2 x 6 volt coils are preferred for racing) then this is the total resistance of the coils wired in series. To measure resistance, use a multi meter set to Ohms or Resistance. Zeroise the needle with both wander leads touching, and then measure the resistance between the low voltage terminals of the coil, or in the case of the two 6 volt coils wired in series, the resistance between the + terminal on one coil, and the - on the other (the other pair of terminals being wired together).
• Wiring
• Use good quality spade connectors and soldered joints. Quality wire is a good idea too. This is the "right way". In practice I use all kinds of connectors, some soldered, some crimped. For any connections that could cause a problem, I use insulating tape over the connectors or liquid electrical tape. It is also worthwhile to use earth wires as well as the frame earth. Bad earth connections are one of the most frequent causes of electrical problems.
• General
• It is good practice to mount all electrical components on rubber or otherwise insulate them from engine vibration (care if the casing is used as an earth, or if a heat sink is needed).
• When planning the mounting of components, remember the need for accessibility, either for replacing quickly in the paddock or testing in situ.
• UPDATE - fitted a crankshaft mounted solid state generator (stator and rotor) on drive side of crankshaft. This is a Motoplat unit as used on some 2-stroke competition machines in Europe. Timing is done at the crankshaft, and the only other component is a Motoplat twin output coil. Very simple and reliable. This completely replaces the Boyer system, battery, points etc. You need a special triangular mounting plate bolted to the existing three stator mounting studs, which themselves need to be shortened. The new stator fits into a circular grove in the mounting plate, which allows it to be moved for altering the timing. The stator has to be machined to fit the crankshaft. It's quite a lot of work to set up, but once done, it can be forgotten - it's that reliable, and fits in well with the belt drive conversion. N.B. remember to locktite the mounting bolts and screws - I didn't on initial setup and the mounting plate started to come loose - I caught it just in time, and after the locktite treatment, it didn't happen again.

10. ENGINE

• Crankcase and Engine breathing
• I prefer to use the very latest crankcase manufactured from 1969. These have a ball bearing on the crankshaft timing side (instead of the earlier plain bearing) and, as a replacement to the timed breather, the crankcase breathes through the primary chaincase and to the air through a large hose.
• Crankshaft and Connecting Rods
• I use standard flywheels with some polishing and relief of roughness. Standard rods are carefully assembled - each rod should fall gently when held at 90 degrees and let go. I do not use reground cranks, as I don't trust that the proper radiusing will be done correctly. Standard balance factor is used, although I should like to experiment in the future.
• Camshafts
• I have tried standard three types:
• T100R Daytona cams (0.0314" lift)
• Reground T100R cams (0.0340" lift)
• Megacycle #512-N351 (Norris 351 grind) (0.368" lift)
• The Megacycle 512-N351 made slightly more power than standard but moved the power band higher in the rev range and narrowed it. Very little happened under 6,000 rpm.
• The reground T100R cam made slightly more power, power band remained wide, but the inlet valves kissed the pistons.
• Currently I use the standard T100R Daytona cams on standard timing.
• Also available from Megacycle are 51260 which have been recommended by other racers
• There must be more potential in this area which I have not yet exploited. Certainly much money can be spent!

• Oil Pump
• I am using two types of oil pump
• Large capacity Triumph double plunger type from early 70's 650 (Morgo also make a large capacity double plunger pump which fits right on)
• Morgo rotary pump. This provides a very good flow of oil (3 pints per minute) and fits right on (you may need to cut away the inside surface of the outer cover to prove clearance.
• One problem you may experience (more likely with the rotary pump) is too much oil in the crankcase with the resulting drag on the flywheel. This is because the higher oil pressure, generated by the pump, will trigger the pressure relief valve and the excess oil is routed to the crankcase. One fix for this is to drill from the outside casing into the excess pressure chamber of the pressure relief valve (be very careful not to go into the pressure side!). Tap the hole and screw a threaded pipe into it (for extra security it can be welded provided it is alloy). Now you can attach an oil line and route any access oil back to the oil tank. I use a new return entrance made in the top of the oil tank. In that way there is no interference with the normal oil returning from the pump to the tank.
• Another potential problem is that the high oil pressure may invert the crankshaft oil seal on the timing side. Dave Quinn sells upgraded oil seals that will take the pressure.

• Barrel and Pistons
• Standard barrels are used with whatever pistons are available. Oversize max is 0.060", and compression ratios are around 9.5:1. Pistons are balanced and stress points/sharp edges relieved. We take a lot of care to ensure the barrels are bored absolutely straight and then lightly honed. Piston/Barrel clearance is 0.005". Barrels and Pistons are assembled with WD40 for rapid break in.

• Cylinder Head
• This is a critical performance area and major gains in horsepower can be made (dyno readings of a standard engine with special head, showed 45 bhp at the rear wheel at 8,000 rpm)
• Our head has been ported to 30mm and flowed by John Parker Racing Heads in Montreal, with oversize valves (Harley Evolution valves and guides - modified), titanium collars and 200 lb. rate valve springs. Flow rates increased from 58cfm for a standard head to 82.8cfm for the Parker head.
• Valve springs are sourced from R&D. Care, standard kits come with #1010 springs, but we use #1006 springs, which give approx. 200 lbs. pressure at 0.345 lift.
• Valve lift is calculated from the lift at the camshaft plus 10%, to allow for the unequal length of the rocker arms. Thus a standard camshaft has 0.314" of lift which gives 0.345" of lift at the valve.

• Push-rods
• Standard push rods maybe OK, but, with the stronger valve springs, I use racing sets from Alloy Tech. These are larger diameter than standard, are alloy, and have steel tips at both ends. It may be necessary to modify the rocker box gasket to take the larger diameter rods.
• Push rods from the Triumph Trident are larger diameter than the stock 500 push rods, and stronger, but are longer and would need to be turned down.

• Rockers
• Rockers are lightened and polished, with particular attention to making the ends lighter. Spacers are used instead of the spring on the spindle which may reduce friction a little
• To reduce side pressure, the rocker adjuster should be in line with the valve stem both horizontally and vertically. The only way I know of altering the vertical angle is to make up longer or shorter push rods. Horizontal alignment is adjusted with the rocker spindle spacers.

• Gaskets
• I use copper gaskets on the cylinder base, cylinder head, and rocker boxes. Cylinder base and cylinder head gaskets come in different thickness. I use 0.020" on the base and 0.025" or 0.050" on the head. On other joints, Loctite/Permatex Ultra Black is used sparingly.

• Torque Settings
• I use the recommended settings from Stan Shenton's book, Triumph Tuning, which are reproduced below:
• Flywheel bolts 33
• Con rod bolts 27
• Cylinder head bolts 3/8" 25
• Cylinder Barrel nuts 22
• Rocker Box bolts 5
• Rocker Spindle nuts 25
• Oil Pump nuts 6
• Oil Pressure Release Valve 25
• Gearbox Mainshaft (timing side) 40
• Clutch Centre nut 50
• Rotor nut 30
• Stator nuts 20
• Headrace Sleeve bolt 15
• Stanchion bolts 25
• Front Wheel Spindle bolts 25
• Zenor Diode nut 1.5
• Fork Cap nut 80
• Gearbox Sprocket 50
• Care: you will find the inner four cylinder head bolts loosen in service before the outer four do. I have made up a cranked adapter to allow re torquing these inner bolts with the engine in the frame. Ideal for Paddock tuning!

• Ignition Timing
• Standard timing is used, set initially using the flywheel timing tool and then with a strobe.

• Spark Plugs
• Champion - N2, N3, C59, C61

• Oil and Gas
• 110 octane leaded race gas mixed 50/50 with 94 octane unleaded pump gas.
• Mobil 1 synthetic oil, 15W-50

• Engine Revs
• For longevity it is better to keep the revs down to 8,000
• The theoretical "safe" limit is 8,500
• We have seen 9,000 in 4^th gear at Daytona!

11. EXHAUST SYSTEM

• Three exhaust systems have been tried:
• Standard large bore (1.5" outside diameter) pipes, no extensions or megaphones. When fitted to the TR5T they worked well but grounded when cornering.
• Two into one system based upon dimensions from Stan Shenton - "Siamesed system of 1.25" diameter. The two pipes must be of equal length before they join. The length from each valve center to pipe end should be 37.5" with a 17" long tail pipe of 1.5" internal diameter". This setup gave a 10% power boost on the dyno and wide torque band.
• Two into one system based upon a pipe length formulae and Triumph works pipes from the 60's - two pipes from head are 25" long and 1.25" od; the tail pipe in 14" long and 1.5" od: the megaphone is 15.5" long and 3.5" od at the end; the reverse cone is 1.5" long and 2.25" id at the end. Still evaluating - stay tuned.
• Dave Cody of Montreal built the two pipes above.

11. CARBURETORS

• There are several choices, the most popular are:
• Amal Concentric Mk1 28 or 30mm
• Widely used and very available (new as well as used), this was the carb used as OEM on most British bikes of the mid '60,1 and early 70's.
• The body tends to wear badly after some use and the flange is often bowed. Luckily sleeving and machining can cure both of these problems.
• I use these from time to time and my settings are:
• main jet 220
• pilot jet standard
• throttle cutaway 3
• needle jet 106
• needle standard
• needle clip position middle
• idle jet 2 turns out

• Amal Concentric Mk 2 30mm
• More up to date than the Mk 1, the Mk 2 is similar to the Mikuni
• It is meant to flow better than the Mk 1, but I have not measured this. Certainly it is better made. Usually it comes for stub fitting.
• I use these on the TR5T and my settings are:
• main jet 190
• pilot jet 25
• throttle cutaway 3 1/2
• needle jet 106
• needle 2C3
• needle clip position bottom
• idle jet 1 1/2 turns out
• cold start jet 50
• Mikuni 30mm
• I have no practical experience of these on the 500cc, although I use one on my Tiger Cub Road Racer. It works just fine. Main Jets are interchangeable with the Mk 2

11. CLUTCH AND PRIMARY DRIVE

• I use a standard primary drive chain and tensioner, and have had no problems as yet (the Triumph factory used to dispense with the tensioner, because it could break up, and so changed the primary chain often)
• Many racers use a belt primary with good results. I have not tried this set up but would like to. If you, like me, use the latest crankcase with engine breathing through the primary drive, the belt must be capable of running in oil. Alternatively the breathing holes will need filling, an oil seal fitted to the crankshaft (bear in mind that the casing may not be machined for the seal), and a new breather made direct from the crankcase - this could use the timing tool hole to the rear of the cylinders.
• The Clutch is fitted with Barnett friction plates (either alloy or steel).
• The Clutch springs are from Barnett as well, and I rarely suffer from Clutch slip
• Loctite the crankshaft and clutch center nuts
• UPDATE - Fitted Tony Haywood's belt drive and clutch conversion - excellent quality and fit. Very good results with no maintenance required. No wear on belt or clutch plates over two seasons of racing. Ran dry - e.g. open to the air. Care: follow setup instructions carefully. As I am running with the primary open to the air, I needed to block the three small breather holes in the crankcase and fit an oil seal to the drive side of the crankshaft (where they used to be fitted before the primary chain case was used as the breather). I also added a new breather to the right of the crankcase just behind the right-hand cylinder through the casting which used to be used for the distributor. I used a 1/2" brass pipe fitting and plastic breather tube. N.B. this conversion alters the overall gearing by approx one tooth on the gearbox sprocket e.g. 20 tooth with the new set up is now roughly the same as 19 tooth with the standard primary drive.

11. GEARBOX

• No modifications are made to the standard Triumph gear box apart from undercutting gears if the change becomes imprecise, and using a close ratio gear cluster. These are quite hard to find. The first set I constructed from the parts book and ordered individual gears from many dealers (expensive!). The second I was lucky to find in one piece from a fellow racer.
• There are several conditions of gears and gear sets, as well as several conditions of crankcase (and gearbox shell). Be careful, as one condition is unlikely to fit with another condition. Check thoroughly before buying.

11. GEARING

• Optimum overall gearing is easier with a 20-tooth gearbox sprocket - there is very little clearance for this and it is necessary to remove the crankcase protector steel strip.
• Gearing that I use for some circuits, and mph @ 8,500 rpm:
• Shannonville 52/53 108/106
• Mosport 47 120
• Shubenacadie 52/53 108/106
• Loudon 52/53 108/106
• Daytona 43 131 (140 @ 9,000)
• Belnap 52/53 108/106
• Excel chart for 500 gearing choices is available on request

11. BIBLIOGRAPHY

• Triumph Tuning
• Stan Shenton
• Tuning for Speed
• Phil Irving
• Triumph Racing Motorcycles in America
• Lindsay Brooke
• Triumph Twin Restoration
• Roy Bacon
• Triumph Tiger 100/Daytona (Development History)
• J.R.Nelson
• The Racing Motorcycle
• John Bradley
• Sportbike Performance Handbook
• Kevin Cameron
• TIOC Magazine/Newsletter (technical articles)
• John Healey
• Nuts, Bolts and Fasteners and Plumbing
• Carroll Smith
• Motorcycle Restorers Workshop Companion
• Geoff Purnell

11. SUPPLIERS

• Moto Montreal (Chris Stewart 514-932-9718)
• Extensive stock of British parts
• John Parker Racing Heads (514-488-8919)
• Full cylinder head service including flow bench work
• Dave Cody (514-932-5214)
• Fabrication, Alloy welding etc
• John Healey (508-429-4221)
• Race parts e.g. copper gaskets for barrel and rocker box
• Barnett (310-941-1284)
• Cables, clutch springs, clutch plates
• Boyer Bransden Electronics Ltd. (01622 730939 UK)
• Electronic ignition (race and road), coils
• Dave Quinn Motorcycles (203-393-2651)
• Morgo oil pumps, high pressure crankshaft oil seal, fairings
• R&D Valve Springs (Don Rickard 760-948-4698)
• Complete kits incl. Titanium retainers and racing springs
• Megacycle Camshafts (415-472-3195)
• High performance camshafts
• British Cycle Supply (902-542-7478)
• British parts suppliers
• Vintage Brakes (Michael Morse 209-533-4346)
• Selection of racing brake linings
• Vintage Fiberglass Racing Supplies (603-239-6778)
• Seats and Tanks
• Gustafsson Plastics (Leif Gustafsson 904-824-3443)
• Screens made to measure
• Alloy-Tech (217-253-3939)
• Racing push rods, and other performance parts
• Tony Haywood (0244 830776)
  28 Kelsterton Road, Connah's Quay, Deeside, Clwyd, UK CH5 4BJ

• Beltdive and Clutch conversions

ACKNOWLEDGEMENTS

Racing would not be possible without the help and support of friends and suppliers. Grateful thanks to everyone involved in our racing program, including the following:

Guy Connell Moto Montreal John Parker - Parker Racing Heads Team Demented John Gurr, Ken Reagan, Bob Tibbits Bill Magnussen Junior - CMR Dyno CVMG (Montreal Section)

JT Sports - Steve Tucker Marc Cornut Moto International Richard Desmarais Guy Martin Voyages Ariane Travel Champion