1987 Yamaha Banshee Beat To Dune Sweet

To improve shifting, the shift drum was machined to accept a needle bearing which supports the left side of the drum. This allows the drum to turn more easily by reducing friction and preventing the drum from binding.

The shift shaft was machined so the shift fingers turn the shift drum more efficiently. In stock form, the drum is turned only partially with the shift shaft fingers. The rest of the turn is accomplished by the shift detent rollers pushing on the shift star points with spring pressure. This is why when the points become rounded the result is poorer shifting. The shifting was improved by allowing the fingers on the shift shaft to turn the drum farther before relying on the detent spring and roller to finish the shift.

To improve clutch life and holding ability, the clutch center was machined with an additional steel and one more fiber plate for a total of 15 clutch plates. The stock plates were replaced with clutches that have more surface area, increasing the clutch hookup. Barnett clutch springs were used to increase the clutch spring tension. The added clutch grip to the engine wears out the stock basket cushions. We upgraded with a Hinson clutch basket. The Hinson billet basket is stronger than stock and is rebuildable. Even with Hinson parts basket cushions wear out; we suggest you make cushion replacement part of your season prep even if you have a stock clutch.

The kick-starter idler gear comes with a bronze bushing that rides on the transmission countershaft. When the bushing wears out, it allows the idler gear to cock sideways enough to break the snap ring out of the countershaft. This not only ruins the countershaft, but the broken parts are now floating around in the transmission. If the snap ring goes between two gears, you can just imagine the resulting damage. So a steel bushing was installed to replace the stock bronze one, which solves the problem.

To improve reliability and performance of the motor, the crankshaft was checked for runout. If the crank has too much runout (or wobble) bearing life is compromised, and the cases will wear, losing their ability to hold the crankshaft securely in the cases. We trued the crank to reduce or eliminate runout. The crank was then welded to the crankpins to prevent it from spreading or twisting. Plus, the trued crank uses less of the engine's power to rotate a bound rotating assembly, allowing the combination to put more power to the ground - not to mention piston timing. Making sure the cases are within tolerance at the main bearing area is essential. If the cases don't hold the crank securely enough, the crank will move in the cases and break the right-side main bearing at the snap-ring groove. The snap ring is designed to locate the crank, not to hold it in place. To prevent movement, the cases must be in perfect shape. We installed the crank with Loctite Stud & Bearing Mount for further protection.

The Banshee center case had a substantial mismatch at the cylinder base. The step was ground out so the air will transition smoothly from the crankcase into the transfer tunnels at the bottom of the cylinders. Removing the step is good for about 2 hp.Cylinder porting makes the Banshee a lot more fun to ride. There are various porting methods used to make power. This is critical when it comes to an engine build. Make sure you tell the engine builder what you use the quad for so you get the proper porting. For duneing, you need a useable powerband. This is accomplished by shaping and angling the transfer ports to more effectively fill the combustion chamber.The transfer ports are angled so the fuel charge emerges from the transfers and forms a coherent column of gas that sweeps back toward the rear cylinder wall and sweeps up the back of the cylinder walls to the spark plug. This column of gas scavenges the residual exhaust gas out of the cylinder without allowing it to mix with the new charge. This design also helps hold more fuel in the combustion chamber at low rpm. This prevents the fresh fuel charge from short-circuiting out the exhaust port and being wasted before it can be burned in the combustion chamber. Preventing this loss of fuel charge at low rpm will dramatically improve bottom and midrange power needed for duneing.This is key to why LRD's engines are famous for making big horsepower while retaining strong, useable, low-end power.The exhaust port is also reshaped for better breathing. Added boost ports are put in the intake port. To further improve performance, the cylinder is bored by 1 mm to slightly increase engine size to a 65mm bore. The piston receives a dry film lubricant coating to the skirt to reduce friction and increase part life. A thermal barrier coating is baked to the top of the piston which improves piston life by reducing piston temperatures. This also keeps the heat on the fuel which allows more fuel to be used. This of course also enhances performance.

It's easy to recognize an LRD ported cylinder. Like many companies, LRD marks the barrel with a serial number that provides vital stats for that specific build. This way, with a simple phone call, LRD knows exactly what you have and what has been done to the bike. The stock head was replaced with the Pro Design Cool Head since we find that the Cool Head helps reduce water temp. The head shell holds and moves more coolant than stock and uses O-rings to seal rather than a head gasket. The elimination of the head gasket removes a heat barrier between the cylinders and the head, allowing the relationship between the head and cylinder to be more thermally efficient. The Cool Head's interchangeable combustion chambers allow compression to be adjusted to match altitudes and fuel octane.

Skinless, the Banshee won't win any beauty contests, but the FullBore plastics (see lead photo) help top off the quad with a killer new look. The front section is a one-piece design with a radiator cap hole. This helps when it comes to keeping an eye on the fluids because the stock plastics don't provide an access hole to the radiator.

We wanted good all-around power for duneing; we didn't want to kill the torque. These Keihin 28mm carbs were bored to 30 mm. The small inlet of the 28mm carb really increases the air velocity, which helps the 350cc motor pick up a little on the bottom end.

RIS Designs has a plethora of polished aluminum parts for most quads but especially for the Banshee. This front grab bar is one of the many parts we opted to use on our beat-to-neat buildup.

FullBore Innovations has aftermarket plastics for the Banshee. The plastics come in a one-piece front section with no fenders up front. The rear can be ordered with or without fenders. This quad is mostly ridden in the sand, so we opted for no rear fenders. This retains the streamlined look of the front and carries it through to the rear.

Trail Tech also manufactures some cool components for the Banshee, most of which have a functional element built into them. Such is the case with these 35-watt Torch halogen light kits that fit in the stock Banshee mounting location.

Sitting is not the optimum position for aggressive riding. Trail Tech has a way of making interaction with the quad ergonomically correct by adding a riser to the 6061-T6 billet aluminum handlebar clamp. Plus, the handlebar clamp adapts the quad to a 1-1/8-inch clamping point for strength and tapers back down to 7/8 inch to fit stock controls. Trail Tech's X-Bars are ultra-strong, reduce vibration, and are made from heat-treated 7075 aluminum.

Razorback Designs will custom-cover most any ATV or motorcycle seat. The design can be chosen from a list of patterns on Razorback's website, or your own custom design can be made in the color scheme of your choice. The LRD exhaust pipes are excellent for both power and sound. The only unfortunate part is that when LRD assembles the silencer it doesn't seal the can to the ends with some sort of RTV sealant; this allows the exhaust to blow two-stroke oil past the silencer at each end where the end pieces are pop-riveted together.

ITP's introduction to the sand market with the Sand Stars rear paddles is truly an entry-level consumer's dream. The rear paddles with mini-scoops provide good traction and excellent handling characteristics. The front dual-rib construction provides good steering traction. The smaller double-rib design has excellent surface area for turning without the need for a tall rib that may flex under hard cornering, plus it won't fatigue while sitting on hard surfaces for prolonged periods of time.