Product FAQ

A:  We recommend non-synthetic Type 'F' automatic transmission fluid (ATF) for use with all our wet primary Pro Clutches. This ATF is designed to produce maximum torque transference via a higher friction coefficient in these type of applications.

A:  Total belt deflection (up and down movement), should not exceed 1/2" and should be not less then 1/4".

A:  Total belt deflection (up and down movement), should not exceed 1" and should be more then 1/4".

A:  The belt that comes with your Brute III Extreme belt drive kit is 1.750" wide with a Kevlar core  wrapped in a polyurethane jacket and the tooth pitch is 11mm GT2.

A:  The belt that comes with your Brute IV belt drive kit is 3.00" wide with a fiberglass core  wrapped in a rubber jacket and the tooth pitch is 8mm HTD.

A:  We at Primo Belt Drives consider many things when we design our drives. Among them are quality, reliability and safety. We believe that using a four inch or wider belt drive puts excessive outboard pressure on the output shafts. This will very negatively affect the life of the shafts, bearings, and seals. They also limit road clearance.

A:  As a rule we do not sell direct to retail customers. We prefer that you contact a local Primo dealer where you will probably be able to negotiate a better deal and also cultivate a lasting relationship for other parts, accessories and service. However, if you find that there is no dealer in your area that you can go to, we will in those instances sell retail direct. However, we do not discount our suggested retail prices for any reason.

A:  No. The Brute II & Brute II Classic belt drive kits that we formerly sold with an idler fit 1965-1984 4 speed or 5 speed Big Twins that utilize an aluminum primary cover. The replacement belts are 1 ½" wide, 11mm tooth pitch and can be purchased either with a fiberglass core or a Kevlar core. Our new enclosed belt drives called the Brute II Extreme do not use an idler and use a new & stronger 1 ½" belt made of Polyurethane and Kevlar. These new belts WILL NOT retrofit to the older Brute II belt drives. The applications are the same as the Brute II except the new Brute II Extreme will not fit 5 speeds.

A:  The idler assembly was created to take up the slack in the belt. However, they tend to be another source of friction on the belt lowering life expectancy. We are now manufacturing 8mm Brute & 11mm Brute II Extreme belt drive kits, where the belts are made to the exact length needed and no longer need the idler.

A:  Our 2 piece motorplate provides additional strength and allows for easier installation. It also gives you the capability in many applications to maintain optimum belt tension.

A:  Unfortunately, we are locked in to specific belt lengths which restrict us to certain pulley combinations.

A:  Absolutely! Our pulleys are designed for ease of installation and flexibility in application by utilizing a removable shaft insert. We make offset inserts for both our enclosed and open belt drives up to 2 inches in length. We can also custom manufacture inserts to any size with special pricing and approximately 2 weeks lead time.

A:  In 1994 to 2006 Big Twin applications (except 2006 Dyna) Harley Davidson changed the Big Twin ring gear from 66 teeth to 102 teeth. The problems start when the compression of the engine increases, thus making it much more difficult to turn the ring gear. The added pressure results in the narrower tooth on the 102 ring gear to fracture. The tooth on the 66 tooth ring gear is substantially wider and less prone to breakage. Rivera Primo recommends the 66 tooth ring gear in all high compression applications. We also manufacture a 84 tooth ring gear. Note that all three types of ring gears must be mated to the correct pinion gear.

A:  We recommend using the using a Primo 3" Open Belt Drive on most motors larger then 113 inches. Of course, the amount of torque and horsepower can differ widely between engines regardless of size. The width of the belt is the constraining factor in regards to how much power you can put through the belt. The Evo and Twin Cam Brute III Extreme enclosed belt drive uses a Kevlar corded 1 3/4" Urethane belt capable of handling horsepower in the 150 + range.

A:  Yes! Our Pro Clutch is inherently easy to pull in due to the diaphragm spring design, as well as the 3 different springs we manufacture for different size engines. If your motor is producing torque in excess of 120 ft. lbs. we recommend using the TPP Variable Pressure Clutch Assist which utilizes centrifugal force to aid in pushing the pressure plate against the clutch pack. Consequently we can use a very light spring, reducing the amount of pressure it takes to pull in the clutch lever while still be able to handle horsepower in excess of 250. For those people with disabilities in their hand or wrist, we offer the fully centrifugal Centri Force Auto Clutch, which allows you to shift or idle in gear without using the clutch lever at all. The Centri Force Auto Clutch is available with most of our open belt drives.

A:  To adjust the height of the diaphragm spring. The small shims go directly on top of the 4 studs and allows for more arch in the spring, while the big shims go under the 4 nuts and help to flatten the spring.

A:  Put two small drops of blue (242) threadlocker on the transmission mainshaft nut and torque to 60-90 ft. lbs.

A:  With a splined shaft the clutch hub will pull off by hand, on a tapered shaft you should use the Rivera Primo Clutch Hub Puller part # PC-2000 or PC-4000.

A:  Generally, the black spring is for stock applications, the silver for motors with torque ranges form 90 ft. lbs. to 130 ft. lbs. while the gold spring is for racing 

applications. On bikes with more then 130 ft. lbs. of torque, we recommend the TPP Variable Pressure Clutch Assist.

A:  From Rivera Primo or an authorized Rivera Primo dealer.

A:  This could indicate that the clutch is not adjusted properly. Proper clutch adjustment should be done as follows:

Turn out the cable adjustment until the clutch lever rests against the grip. Turn the center adjusting screw out and then turn the center screw in until the clutch lever just starts to move away from the grip, then turn the center screw out ¼ of a turn and lock the center adjusting screw jam nut firmly against the pressure plate. Now adjust a black cable so you have approx. 1/8" free play from the clutch cable ferrule to the clutch lever perch and on a braided cable you will have almost no free play.

A:  This is due to the fact that an open belt is run with out an enclosed housing, compared to stock which is enclosed and muffled with oil. The noise you hear are the clutch plates tapping against the inside of the clutch shell.

A:  No. The Pro Clutch is manufactured differently to outperform other clutches. You should use only Genuine Rivera Primo clutch friction plates and steel drive plates manufactured specifically for the Pro Clutch.

PC-1000-A  –  Fits 1936 – 84 Pre - Evo Big Twins (40 % more surface area then OE)

PC-1100-CA – Fits 1986 – 89 Evo Big Twins ( 325% increase in friction plate surface)

PC-1200-CA – Fits 1990 – 97 Evo Big Twins  (100% increase in friction plate surface)

PC-1298-CA – Fits 1998 – 06 (except 2006 Dyna) Big Twins (100% increase in friction plate surface)

1056-0020 – Fits 2006 Dyna & 2007 Later Big Twins

PC-1300XL – Fits 1991 – Present XL Models

* Simple bolt-in installation

* Smooth & easy hand control

* Three diaphragm springs available; stock, street competition, & race

* Double row sealed bearing replaces loose rollers and cage (PC 1000 & PC 1000 C)

* Wet or dry application

* Stainless steel or billet aluminum pressure plate

* Sealed bearing provides stable hub rotation & eliminates vibration