Draft Cycle Works

Monday, May 18, 2015

Rock Flute Specifications:

For my own notes and for those interested, here are the specs on Rock Flute.  I'll update this as things change... because they always do. For instance, the green paint in the picture is actually a brighter green than the color code listed below.  I will update the picture as soon as the bike is repainted.

Engine:
10.9 to 1 CR
1978 CB750 F bottom end
1976 K model cylinders, Decked
1976 K model Head, Stage II porting, decked by Mike Reick
                33.5 mm OS intake valves, stock exhaust valves
                Megacycle 125-75 cam, 0.005” Int/Exh tappet clearance, 105 int 104.5 exh lobe centers, no adv.
                                (More cam specs in chart below)
                Adjustable cam sprocket
                HD Valve springs and titanium keepers
                Late model cam towers with unbolted early model rocker shafts
Wiseco 836 forged piston kit
CycleX Super Rods
New primary chains installed
Reinforced valve cover with cam tower stabilizers

Transmission/Final Drive:
F model transmission, backcut with close ratio 4th and 5th gear
             Primary: 1.708:1
            1st:           2.500:1
            2nd:          1.708:1
3rd:           1.333:1
            4th:           1.133:1
5th:           0.969:1
Barnett Clutch plates and springs
Drilled clutch basket with oil grooves for added oiling
Final Drive: 17/48 2.82:1

Ignition:
Dyna 2000 ignition with 3 ohm Dyna minicoils
Total Timing Advance: 35*
Timing curve: 4 (changed 6/12/15 from 5 which may be causing low/mid stumble)
Rev limiter: 10,500 RPM
NGK DR8EA 5 kohm Resistor type spark plugs @ 0.036” (resistor plugs used to eliminate noise in digital tach and increase spark duration)

Fuel/Intake:
Ramflo Filters
Sudco VM29/CB750 Adapter boots with vacuum ports
Mikuni VM29 Smoothbore Carburetors
               Mains: 120
               Pilots: 12.5
               Air Jets: 0.9
Air Screws: 1.5 Turns
Jet Needles: #5DL31 with clip @ #5
Needle Jets: 0-6
Throttle Valves: 1.5
Float Height: 23 mm

Exhaust:
4-2, 2” long baffle with 1.25” inner diameter

Frame:
Cycle One Manufacturing rigid
2" forward
4" up
36* rake, Harley 1" neck
5" ride height
Paint: Sikkens Rally Black
Body:
Fuel Tank: 1969 Triumph Tiger Daytona 500
Rear Fender: 5" Ducktail ribbed fender, 7 Metal West
Paint: Mopar F8 Green / Nissan Obsidian Black / Ford Graphite Metallic
Seat: Satin black powder-coated Accufast seat pan with single leaf spring suspension
Suspension/Front End:
Square lef girder with Honda Rebel shocks mounted behind legs to the lower rocker studs
Wheels/Tires/Brakes:
Front Wheel:  Satin black powder-coated SOHC CB750 rim laced to a CL450 dual leading shoe brake hub
Front Tire:  Shinko 705 110/80-19
Rear Wheel:  Satin black powder-coated DOHC CB750 rim laced to a late model CB750 drum hub
Rear Tire:  Shinko 705 130/90-19
Gauges/Info Center:
Vapor Computer System
     Speedometer, Tachometer, Trip/Odometer, Top Speed, Time, Head Temperature, Shift Lights/Redline Warning
Analog Oil Pressure Gauge
Lighting:
Headlight:  Cycle Standard 4.5 inch early style headlight with high beam indicator
Taillight:  Bullet style dual filament

Oil:
Capacity: 3.5 Quarts
Mobil 1 20w-50 Full Synthetic

Fuel:
Capacity: 3.7 Gallons
Premium 91+ Octane

Curb Weight:
450 Lbs


Cam Specs
Valve Lift
Duration
Int. Open
Int. Close
Exh. Open
Exh. Close
Lobe Center
Overlap
tappet Clearance
Sealed Duration
Int.
Exh.
Int.
Exh.
BTC
ABC
BBC
ATC
Int.
Exh.
Calculated
Int.
Exh.
Calculated
Megacycle 125-75
0.400
0.375
262 @.04
257 @.04
26
56
53
24
105
104.5
50
0.005
0.005
251

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