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Restoring a 1970 BSA A65 Firebird Scrambler.


Table of contents


Introduction

This 1970 BSA A65 Firebird Scrambler was bought in 1993 in a miserable condition with many parts missing. However, the bike had a spare engine with a hole in the crank-case from a thrown piston rod that had matching numbers with the frame and I decided that my search for a project bike was over. The bike was taken apart completely and a trial assembly was done during a period of two years.

During this time all the missing parts were sourced in Great Britain, USA and Sweden. My intention was to use only New Old Stock (NOS) parts but this intention had to be abandoned due to obsolete cycle parts. However, new pattern parts were in many cases available at reasonably prices and proved to be, after some disappointments, of very high quality. In many cases parts were sent back to the supplier as they did'nt meet up to acceptable standards.

The purpose of the restoration was to create a classic looking motorcycle with all the charm of brit bikes from the golden era, yet be able to use the bike for all kinds of purposes including modern city stop-and-go traffic.

The following pictures show most of the modifications and restorations undertaken. The bike was finished in 1997 and sounds and run just as good as it looks!

If anyone is about to venture out on a similar restoration, please feel free to contact me!

Ride'em, don't hide'em!

Richard Trygg
richard@ingfatrygg.se

Suppliers


The following suppliers has been used throughout the project:

SRM Engineering

SRM supplied some engine parts including a new cylinder head, 750 cc cylinders and pistons. They did most of the engineering work such as:

SRM claims to be the largest supplier of engineering services, aftermarket conversions and parts for BSA in the world.

Comment:

To use SRM parts proved to be worst mistake of all in the project as some parts were of poor quality. The list below describes the worst cases:

The worn out camshaft cost me one riding season and almost 100 hours spent in the garage dismantling the entire engine, cleaning it out and checking for damage caused by metal particles.

SRM admitted to the above and supplied new parts, gasket sets etc. but since delivery time from them was long it all took the entire riding season.

The engineering work undertaken by SRM in general spanned from questionable to excellent which might indicate that the problem is quality assurance related.

Since this restoration SRM has continued to grow as a supplier and are considered quite reputable. Hopefully the problems with quality control has improved by now.


http://www.srm-engineering.com/

TMS of Nottingham

TMS supplied both engine and cycle parts and seems to have a large stock of spares for most Brit bikes. Good products, many NOS parts and good quality pattern parts. Highly recommended supplier.

TMS 92-94 Carlton Road
Nottingham NG3 2AS
Tel (0602) 503447
Fax (0602) 503556
Great-Britain

Gustav Johansson

This gentleman is the former BSA agent in Sweden and was still in operation in 1995 and I hope he still is!
He sells NOS parts as well as some used parts and pattern parts. He supplied my rear mudguard and chainguard both were pattern parts of higher quality than NOS parts and still at reasonable prices!

Gustav Johansson
Kornhillsvägen 17D
302 58 Halmstad
Sweden
Tel. 035-128002, 111863

Central Wheel Components

CWC supplied the steel rims, stainless spokes and nipples. Excellent quality and reasonable prices.

Central Wheel Components
Lichfield Road
Water Orton
Birmingham B46 1NU
Great-Britain
Tel. 021-7475175
Fax. 021-7496688

Birka Motorrenoveringar

Machine shop that mostly renovates car engines but also performs work on motorcycles, specialising in BSA. They also have a stock of NOS engine parts for BSA. Excellent services by highly competent personal. Better choice than SRM for machine work such as regrinding, reboring and assembly work. Talk to Mattis.

Birka Motorrenoveringar
Rosenlundgatan 52
104 62 Stockholm
Sweden
Tel. 08-845767, 844080
Fax. 08-849264

Bri-Tie Motorcycles

Provides a variety of services including engineering work. Specialises in tank repair, chroming and paint. Bri-Tie provided the paint, Flamboyant Red, and Silver Sheen for the front hub. Excellent service by true enthusiasts, highly recommended!

Bri-Tie Motorcycles
Cwmsannan House
Llanfynydd, Carmarthen, Dyfed.
SA32 7TQ
Great-Britain

A.O Services

Specialises on electrical systems for classic brit bikes. Very personal and competent service from a small and dedicated supplier. A.O Services supplied all electrical components including a DIY loom kit and a hard to find light switch. Highly recommended supplier.

A.O Services
35 Griston Road
Watton, Thetford
Norfolk IP25 6DN
Great Britain
Tel/ Fax: 01953 884681

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Engine

The engine was given the full treatment with all the available alterations from SRM Engineering: As the engine was in a miserable condition only the crankcase halfs, crank-shaft and gearbox axles were reused. Remaining parts were replaced with NOS parts, or SRM parts which proved to be a mistake! The hole in the crankcase were welded by SRM and turned out invisible!
The crankshaft during the initial part of assembly. The connecting rods are std BSA with steel end cap supplied by SRM. Left side shows the end feed conversion for oil supply.

Timing side of engine after fitting of camshaft and idler pinion. Here the combined roller/ball bearing shows. The single race of balls serves as a thrust bearing.

Overview of timing side.

Overview of primary drive side.

The SRM jumbo kit. Bore size is now 79.5mm with standard stroke of 74 mm, this gives 734 ccm. Compression is the standard 9:1 but higher ratios are available. Note the O-rings in the front oil return holes.

Setting up the Boyer-Bransden micro digital ignition statically. Later this is done dynamically with a strobe light to exactly 34 deg BTDC.

Close-up of the Boyer-Bransden ignition. Be sure to cut the center screw for the rotor to correct lenght.

The Lucas RM 24 stator was standard equipment for late model Triumphs and is encapsulated. Here the aluminium SRM clutch plate shows. The plate has a roller thrust bearing which makes it lift straight out to avoid drag. The clutch works very well with this setup.

Parts for the cylinder head ready for assembly.

The SRM flow ported head with 32 mm inlet valves. The valves are stainless steel. Unfortunately the head was supplied with damaged threads for rocker cover and spark plugs.

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Oil tank

The back plate of the oil tank was cut off to enable cleaning and the sight was a real surprise! Leafs, bugs and a candy wraper was removed and severe rust damage revealed! An additional oil tank was sourced on a swap meet, cut open and the best part of each tank was welded together.

This is what one can expect to find in a 30 year old oil tank!

Thats better!

The back plate from a swap meet bargain was in better condition than the original one.

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Front forks

The front forks on the late model pre-OIF is a excellent piece of engineering and can be compared with many forks of today. The model from 1968 to 1970 are the best in my opinion since it has the shuttle valve that prevents bottoming-out. All moving parts were replaced by new parts from TMS and are pattern parts of high quality.
All parts required for a complete restoration. Only the bottom fork legs was reused from the original bike. The inside had to be honed since it was slightly damaged.

A pipe vice and some copper sheet metal makes a good support.

A homemade tool with brass screws to fit the holes in the chromed seal holder.

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Front wheel

The front wheel was restored back to its original condition with the help of a Dunlop type rim from Central Wheel Components, stainless steel spokes and nipples. The hub was turned and brake linings of a modern type was fitted by a local brake shop.
All components needed to respoke the wheel. Permanent lubricated bearings were fitted. The hub was resprayed with the original Silver Sheen paint.

The wheel was laced in the front fork with a precision dial.

Ready to be installed on the bike. Tire is Dunlop TT100.

Not only does it look good, it provides two-finger stopping! The brake levers are chromed which is not original but looks nice!

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Rear wheel

The rear wheel on the 1970 BSA's and Triumph's is of the famous quick-change type that sadly was replaced by the conical hub on 1971 year models. The wheel can easily be removed without taking of the chain. The brake might look like a bicycle brake but set up correctly supplies ample stopping power.
The famous crinkle hub, shotblasted and ready for paint.

All components prior to lacing. Remember to measure offset before the original wheel is taken apart.

The finished wheel installed on the bike. Tire is once again Dunlop TT100.

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Frame

The double downtube cradle frame of the A50/A65 is undoubtedly one of the best frame of the sixties and can hold its own even compared with many modern frames. Roadholding is excellent and the frame was often used in specials as TriBSA's as the frame is stiffer than its Triumph counterpart. There is only two servicable points on these frames and thats the swingarm bush and the steering head races. Many of the bikes from the sixties and early seventies has had experienced som rough times so always check that the frame is straight before painting and reassembly.
The swingarm with the bushings removed. They are very thin, so easy to remove. A tool is necessary to install them undamaged.

Here the new bushings are installed. They are not always necessary to replace since they are unstrained and if well lubricated should last almost forever. In this case they needed replacing.

Here the frame is in its initial state of trial assembly with the swingarm installed. The steering head bearings are replaced with the SRM conical bearings, a recommended modification since this actually improves handling.

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Electric system

Many of the problems with classic brit bikes can be related to the electrical system. Since I had previous experiance with this, I decided to go all the way with this. The Boyer-Bransden micro digital ignition system must be considered the single most important modification to be made to any classic brit bike. Not only does this make the contact breakers obsolete, starting is easier and idling improved. Secondly, I decided to use the power box from the same manufacturer. This, together with the RM24 alternator, gives a 3-phase 180 W power output. This is really for electric start machines but since the wiring gets simpler and more reliable I opted for this system. All wiring was redone with equipment from AO Services and all the switchgear was replaced with NOS parts. All connections are soldered and not pressed.

The bracket for side panel mounting were modified to take the Boyer-Bransden electronic ignition unit. The small box is simply strapped down with a reusable wire strap.



This is not an ideal position for the power box as some of the extra heat has to be ventilated away. No problems so far might be due to Swedish riding conditions which allows for excellent cooling!!



The Wipac Tri-Consul light/horn/kill switch were one of the components hardest to find. NOS item from AO Services.

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Paint work

Through the BSA Owners Club I got the information that the colour of this export model was called Flamboyant Red. Bri-Tie supplied the paint and also could deliver the original Silver Sheen used on the front hub. Since these paints were delivered as cellulose enamel, I decided to only use the Flamboyant Red as a colour match. A piece of sheet metal was given the three layers of coating. First the gold base is applied, then the transparent red and finally a couple of coats of clear laquer.
The colour match was given to a local paint supplier who stirred up a batch of modern car paint to the exact colour match. This is applied in the same manner as the cellulose but have a catalyst hardener to give it a glas hard surface.
The frame, fork shrouds and lower legs as well as some brackets were painted the original black. Instead of using the now so popular powder coating I decided to go with normal 2-component car paint since this is very easy to touch-up if minor damages occur.
I performed all the paint work myself in a well ventilated garage at approx. 23 deg. C with excellent result.


The tank emblem in all its glory. These emblems disappeared on the OIF models.



The chrome knee grips with white lining only found on the 1970 year model.



The steel sidecovers were fitted with transfers provided by the BSA Owners Club.


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Photos of finished bike





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