Harley-Davidson Motorcycles Jackshaft Assembly
Big Harley-Davidson motorcycles are tough on starter motors and starter system mechanical components.
Tech Tips: Repairing and Servicing Fuji 400, 450, 500 and 550cc Engines
Many of the engines that power Polaris ATVs are liquid-cooled, single-cylinder, SOHC 4-stroke units manufactured by Fuji. The 400, 450 and 500cc engines are nearly identical outside of bore and stroke. The newer 550 engine is updated, but some of these tips still apply. The 570 engine has a DOHC head and is unrelated for
Simple Steps to Prepare Your Powersports Battery for Winter
As winter approaches, many powersports vehicle owners will need to store their vehicle until the spring. Maintaining the battery state of charge during extended periods of storage is essential to ensure that the maximum service life is delivered. Owners should also note that many newer-model motorcycles have more key-off drains than previous models. This makes
Replacing Gaskets and Seals
Servicing and repairing powersport vehicles requires replacing gaskets and seals on a regular basis. Trying to reuse seals and gaskets can leave a technician in a world of hurt and wasted time redoing work. Always be prepared to replace any seals and gaskets that are removed during a service or repair procedure. Don’t accelerate the
5 Steps to Setting Sag the Race Tech Way
Static Sag or “Race” Sag is the amount the bike compresses from fully extended, with the rider on board. Here’s how to measure it the Race Tech way. It is a little different than how you may have done it before but is much more accurate as well as consistent. This instruction uses a Sag
Servicing Ball Joints
Front A-arms generally use spherical bearing ball and socket joints to connect to the steering knuckles. The steering tie rods connect to the steering shaft and knuckles with ball joints, and they can be used to connect rear A-arms to a stabilizer bar via a tie rod. These ball joints can be damaged and wear
Engine Decompression Systems
The decompressor system reduces cylinder compression at low rpm for easy starting. Decompressor systems are often used with single cylinder four-stroke engines, but manufacturers sometimes utilize these benefits on other engine configurations including V-twins. The compression is reduced by momentarily opening an exhaust valve on the compression stroke of the piston to partially vent the
CV Axle Boot Repair
The CV axle boot is a weak link in the final drive systems of four wheel drive ATVs and Side-by-Side vehicles. If the boot is damaged the joint can lose its lubricating grease and pick up debris to contaminate the joint. If the boot damage or deterioration is not addressed it will lead to a
The ‘Mysterious’ Little Black Box
Computer, Igniter, CDI, ICM, ECU, and ECM are all names for the black boxes that are the brains behind modern engines. Depending on the type, they control ignition, fuel injection, ABS, display meter or a combination of all. They are very important and often very expensive. Unfortunately, they often unnecessarily take the blame for mysterious
Diagnosing Yamaha’s EFI Self-Diagnostic Systems
For years now technicians and educated vehicle owners have enjoyed the benefits of the self-diagnostic functions of fuel injection systems. Evaluating fault codes is now a standard task in powersport vehicle service. Some fuel injection systems have expanded onboard diagnostic abilities that can be used to troubleshoot issues in addition to the simple fault codes.
Mechanisms of Fuel Delivery: The Float Valve
In a previous issue we went over mechanical fuel delivery system problems associated with carburetor equipped engines. The final mechanism of fuel delivery to the carburetor is the float valve. The float valve is a fantastically simple mechanism to regulate fuel needs for the carburetor. Unfortunately, it is often problematic when fuel is left in
Gravity and Vacuum Fuel Pumps: Maintaining Efficiency
Old fuel is clogging up fuel systems and seals are deteriorating as power sports vehicles sit idle over the cold winter.