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Francis-Barnett Motorcycles

Francis-Barnett Model 87 Falcon

Technical and Service Information

The following information is from the Instruction Manual for this model, published by Francis & Barnett Ltd:

Engine 20T two-stroke
Cubic Capacity 199cc (11.8 cu ins)
Stroke 72mm (2.866 ins)
Bore 59mm (2.3228 ins)
Rebore Sizes 0.015" & 0.030" Oversize
Compression Ratio 8.5 to 1
Ignition Timing Points begin to open 5/16"
before TDC
Contact Breaker Gap 0.012"
Sparking Plug Type Lodge CCL 14
Sparking Plug Gap 0.018" - 0.022"
Correct Lamp Bulbs Head - main

Head - pilot
Tail
Speedo
6v, 30/24w, twin filament
pre-focus

6v, 3w MBC
6v, 18/3w
6.5v, 0.3amp MBC
Carburettor Amal Monobloc 376/231
Choke bore 1"
Main jet 180
Pilot jet 30
Slide No 3½
Needle jet 0.106"
Needle position - 2nd notch from top
Sprockets
(Standard)
Engine
Clutch
Gearbox
Rear Wheel
18T 3/8" pitch
43T 3/8" pitch
18T 1/2" pitch
50T 1/2" pitch
Chains Primary
Final Drive
3/8" x 1/4" x 0.225", 58 links
1/2" x 0.305", 121 links
Rear Chain Adjustment (Machine on stand) 1¼" whip approx.
(Rider Seated) ½" to ¾" whip.
Overall Gear Ratios
(Standard)
4 speed
6.5, 8.6, 12.0, 19.1 to 1
Hub Bearings Front
Rear
15 x 35 x 11mm
15 x 42 x 13mm
Internal Gearbox Ratios 1.0, 1,3, 1.85, 2.95 to 1
Engine Main Bearings Drive Side (2)
Flywheel Side (1)
3/4" x 1 7/8" x 9/16"
3/4" x 1 7/8" x 9/16"
Engine Big End Bearings Steel Rollers (8) 1/4" x 3/8"
Steering Head Bearings 1/4" balls - 19 top , 19 bottom
Wheel Rims WM2 - 18 front & rear
Tyres 3.25 x 18 L/W front & rear
Tyre Pressures
(Normal Solo)
Front
Rear
16 lbs/sq in
24 lbs/sq in
Spokes Front R/H
Front L/H
Rear
10 swg x 6 3/4" (18)
10 swg x 6 5/8" (18)
10 swg x 6 9/16" (36)
Brake Drum Diameters 5" front & rear
Brake Lining Width 3/4"
Total Braking Area 13 sq ins
Fuel Tank Capacity 3¼ gallons
Fuel Mixture Petrol/oil ratio 20 : 1 (see below *)
Oil Capacities: Chaincase - fill to drain plug level
Gearbox - fill to level screw behind
K/S crank
Forks - per leg
 
175cc
1 litre

55cc (one petroil filler
cap measure)
Wheelbase - static 49¾"
Seat Height 30½"
Ground Clearance 6"
Width Over Bars 26"
Overall Length 78"
Approx. Weight 267 lbs

* - Editor's Note: In the manual, a petroil ratio of 16:1 is recommended for Castrol and "MobilMix TT" 2-stroke oils. However, modern semi-synthetic 2-stroke oils can run at higher ratios (where in accordance with the manufacturer's instructions), and will produce less pollution and carbon build-up.

From an archive of www.users.zetnet.co.uk/Francis_Barnett/ For more information on this page visit Emu Archives



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