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SCR/Moto Carrera CT1 200GP AHRMA Rocketship!
Scott Clough leads a field of 12 riders into Albuquerque's
fastest corner in his first outing since 1979! |
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The Scott Clough Racing 1971 Yamaha CT-1 175 enduro-based roadracer
uses the stock frame and swingarm, with RD400 rod bearings for swingarm
bearings running on a drilled 400 crankpin for a pivot sleeve. The
steering stem and triple clamps are Yamaha aluminum MX parts, with Moto
Carrera tapered roller bearings at the bottom and stock balls on top. The
front forks, damping rods, springs, hub, and brake, are all Yamaha R-5
parts from Moto Carrera. Rear hub is stock CT-1, with the backing plate
modified for pin-in-slot torque location on the swingarm, and a boss added
for brake cable attachment. I fabricated all the rearset components and
mounts, cables, and removed all unneeded material from the frame and
swingarm. Rims are reconditioned shouldered alloys, in WM2 front and WM3
rear sizes, fitted with Avon 80/80-18 front and 90/90-18 rear roadrace
tires, and laced with stock spokes from R-5 and CT-1. Shocks are
reconditioned Konis. The fairing is an MT125 from SGS compostites,
modified from 2-piece to 1-piece, with all mounts and stays fabricated by
SCR.Gas tank is from an R-5, and the seat is made to match from
fiberglass. Total wet weight is approximately 190lbs.
The engine has a Scott Clough Racing weighted and balanced crankshaft with
a YZ connecting rod from Pro-x. A modified Wiseco 66.5 mm piston is used
in a CT-1 cylinder with Scott Clough Racing porting, and the intake is
welded and machined to accept a 28mm Mikuni rubber manifold, securing a
Mikuni VM30 carburetor with SCR mods to fit the manifold and increase
airflow. The head is a vintage Webco head, machined by SCR.The stock CT-1
wide ratio transmission is currently being used, until I can secure an MX
close ratio box. The engagement dogs are undercut, and all motor parts
have been cryogenically treated to increase strength and reduce friction.
The clutch uses Barnett friction plates and shimmed stock springs, and can
just barely hook up the power made by the engine. The pipe is a Moto
Carrera/Tommy Crawford GP pipe, modified only slightly to fit the frame.
Ignition is a YZ125, modified to fit by SCR.
I built the entire bike from picking up the frame and engine parts just
after Christmas 2003, to it's first outing at the AHRMA Sandia Classic in
Albuquerque May 1-2, 2004 in the 200GP class. The bike had no real track
time prior to the event,as the first attempt showed the Ebay ignition I
bought had a bad component. I have not roadraced since 1979, and had to
take the rider certification school at Sandia prior to racing. In the
first race, I holeshot from the 3rd row, and was never challenged, winning
by about 6 seconds in 6 laps. The second race was much the same, starting
from the second row and winning with a similar margin, over about 11 other
riders. No tuning or chassis changes were necessary, it ran at that level
right out of the trailer.
SC
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