|April 2000 Racer Corner||www.virtualindian.org|
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During Indians last fling a small batch
of 4 cam big base racing Scout where put together by Dick Gross and ridden
to success by Bobby Hill. The 4 cam machines where a system that included
the whole machine.
The set up essential used a factory cam
to which Grosses own unique cam lobe was pinned. I've seen one set up where
he was using a factory Savannah came run backwards with his own lobe pinned
to it. He used a factory Bonneville lift with a spacer brazed to the side
of it at one point. He also hand made his own lifts with different
center to center lengths.
The cylinders used a 1/8 over sized inlet nipple brazed in to the cylinder. They also had a 1/8 over intake valve. The exhaust valve was the standard size. They used the m-53 1 1/2 HD carb with the bombsight venturi.
Ignition was by magneto. The oil delivery
to the motor was adjusted by pressing a drilled orifice in to the
back of the aluminum oil pump directly in front of the pinion shaft.
Different sized holes where used. All in all it must have worked
well as they sure did run.
Related VI Articles:
Cam Gallery (photos of Indian cams, including the Gross 4-cams!)
Cam cover patterns and casting
Warpath BB engine cases
Original BB case article
New "Tall Fin" racing heads
Racer Corner 1; Jim's Sport Scout racers
Racer Corner 2; Factory racing tanks
Racer Corner 3; Strengthening your rear frame
Racer Corner 4; Narrowing your forks
Corner 5; Factory 648 instructions & specifications
Timing chest of the 4-cammer
Drive side bearing housing
Drive side housing, external
Nut for bearing housing, the way Gross did 'em
Oil pump with provisions for tach drive
Gross pump left, Daytona under-seat oil tank pump right
Cam covers; iron pump left, Big Base center, Lyle's art right
Stock BB left, Lyle's magic right
BB cylinders left; notice the #s face towards the drive side of the cases rather than the V
Big intake nipple left, stock right
Modified left, stock right