Rivera Primo Brute IV User Manual
2108-0005
INSTALLATION INSTRUCTIONS FOR
It’s common knowledge that a belt drive primary can provide advantages and service that a chain
cannot, especially considering the new technology present in every belt. For dependable, high performance, long-life service nothing beats a modern Primo
®
Belt Drives primary-drive belt-kit!
Primo’s long-time tradition of “Quality & Performance” has made our belt drives the most popu-
lar in the world. That same quality & performance is now available in the Brute IV
TM
3” wide open
electric-start primary belt-drive for most Big-Twin motorcycles. The Brute IV
TM
is ideal for streetperformance, competition, and show-bike applications. It looks as good as it works. Carefully read
and follow these instructions for a quick, convenient installation. If you have any questions regarding this installation call (562) 907-2600 and a PRIMO
®
BELT DRIVES technician will be happy to
assist you!
Use of the word Harley-Davidson, various motorcycle model names & designations & OEM part numbers are for end-user reference or application information
only. No affiliation between Rivera Primo Inc. & The Harley-Davidson Motor Company exists or is implied by the use of said information. Rivera Engineering, ProClutch, Primo, and Primo Belt Drives are registered trademarks of Rivera Primo Inc. Unauthorized use is prohibited by law. law.
IMPORTANT SAFETY NOTE....
When performing any motorcycle work such as installing a belt drive it should be securely fastened in an upright position with
easy access to the primary drive. If you are working with a lift, fasten the motorcycle securely to prevent it from falling.
Always remove the battery to prevent accidental start-up.
Brute IV
TM
Belt Drives
3” Wide
8mm Belt
Fits 1970-2006
Big Twins
(Except Late 1978-86
w/Rotary Top 4-Speed Trans)
BRUTE IV
TM
SHOWN WITH STANDARD POLISHED
ALUMINUM BELT GUARD (PP-419-P-AY),
SUPPLIED IN KIT (NON RUBBER-MOUNT MODELS)
BRUTE IV
TM
KIT SHOWN WITH
OPTIONAL FLAMED BELT GUARD
# 2014-0010
** To prevent serious injury, all
open belt drives must be run
with a full coverage Belt Guard !
www.riveraprimo.com
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HOME OF PRIMO®BELT DRIVES
QUALITY & PERFORMANCE SINCE 1973
1
2
3
STEP 1:
Begin by disconnecting battery cables. Removing all the OEM
primary-drive components including the inner primary cover,
AND THE FACTORY INNER-BEARING RACE ON THE TRANSMISSION MAIN SHAFT! Check the motor shaft & transmission
main shaft for leaky seals. Check & thoroughly clean the motor
drive shaft & trans main shaft. Check & tighten the shift-lever
as needed at this time!
If you wish to change the final drive
ratio, now is the time to install a rear
belt drive transmission pulley (tighten
nut perprocedure outlined in HD factory service manual). Primo’s billet aluminum rear drive pulley is
available with 29, 30, 32, or 34 teeth & weighs 3 pounds less
than the OEM unit.
STEP
2:
Install the starter coupler onto the end of the starter
motor as shown. This component must be installed
prior to the installation of the bearing support.
1986-1988 Sof
tail / FXR applications:
Adequate clearance for the coupler must be made. Remove
approximately .150” of material in the area indicated by the X
(use the 7 o’clock position as your guide).
A 1990 or later starter motor is required. The Primo Belt
Drives adapter plate (PP-407H) is mounted between the
starter motor and the transmission starter boss as pictured.
1970-78 Shovelhead applications (ratchet top only).
A 1990 & later starter motor is required for Shovelheads. A
Primo Belt Drives adapter plate (PP-306) is mounted between
the starter motor & the transmission starter similar to the Softail
adapter.
STEP 3:
Install the bearing support (rear motor plate section PP-304,
PP-404, PP-504, or PP-604). Carefully align the bolt-holes
and install the bearing support over the starter extender. Only
hand tighten the bolts at this time. Attach the 1990 or later
starter motor to the rear of the bearing support (1986 Softails
require an adapter PP-407-I) (1970-78 Shovelhead with
ratchet top requires the starter adapter PP-306).
2A
2
6
5
4
3A
3B
STEP 4:
Install the Motor Plate (front section PP-303, PP-403, PP-503,
or PP-603), start the four front section bolts, but only hand tighten at this time!
Install the 4 center bolts that attach the front section of the
Motor Plate Assembly to the rear section. TIGHTEN THE
MOTOR PLATE BOLTS, THE BEARING SUPPORT BOLTS
AND THE CENTER BOLTS TO 29 FOOT POUNDS OF
TORQUE AT THIS TIME, WHILE ENSURING THAT THE
PLATES ARE PROPERLY SEATED AND ALIGNED. If you
have a PP-400 (show chromed alternator cover) install it now!
STEP
5:
Apply a liberal amount of bearing grease to the transmission main-shaft
splines to act as a corrosion inhibitor. The grease also protects the
splines by absorbing shock-loads & preventing rust.
STEP
6:
Install the starter jack shaft mechanism (extender, spring, pinion gear, thrust washer, lock washer, and bolt). Make sure the
lock washer is correctly oriented. Use 1-2 drops of blue
threadlock & snug the bolt. Bend the locking-tab over to keep
the bolt from vibrating loose.
STEPS 3A
& 3B:
Primo Belt Drives PP-502 Motor Plate assembly (rear section) for
Dyna Glide is notched for swing-arm pivot-boss clearance (photo 3A).
Approximately .125” of material must be removed from the end of the
nut & swing arm pivot bolt assembly (photo 3B) to allow clearance for
the Brute IV starter ring-gear before installing the clutch basket.
Remove enough material from the end of the nut & bolt to allow the
starter ring gear & clutch basket assembly to be installed & rotated with
approximately .100” clearance between the ring gear & the nut-bolt.
PP-400
See page 7 for starter mechanism diagram!
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STEP 7:
Install the rear pulley (clutch basket) and hand tighten the clutch hub nut making sure it is snug. Note that this
nut is left-hand thread. At this time it is important to check the air gap between the back side of the starter ring
gear and the pinion gear. Recommended gap should be .075” to .125”. Use an 1/8” Allen wrench to measure the gap.
Just slip the short end of the wrench between the ring gear & the pinion gear. If it fits, great. If there is too much gap,
the jackshaft assembly should be shimmed to reduce the gap to the spec above (order #1185-0500 shim kit).
Air gap between ring gear
and pinion gear
Measuring the air gap
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