How to Replace the Neutral Switch on a Yamaha Wolverine

by Chris Gilliland

The Yamaha YFM350 Wolverine was produced between 1995 and 2005 to fit the role of a medium-sized utility-type all-terrain vehicle. The Wolverine was powered by a 348 cc single-cylinder, four-stoke, engine with an integrated manuallyoperated five-speed transmission. A small switch, located against the inner left wall of the engine crankcase, was used to inform the Wolverine's rider when the transmission was shifted out of gear and into neutral, preventing the ATV from racing off when it should remain stationary. The neutral switch usually requires little attention but can fail eventually. While the switch is fairly simple and is attached to the engine by a pair of bolts, extracting the switch requires the removal of the engine's primary and secondary clutch assemblies.


Park the ATV on a level work surface and set the parking brake. Let the engine cool for a minimum of 30 minutes.


Remove the seat from the ATV, using the release lever at the rear of the seat cushion. Disconnect the negative battery cable from the battery, located below the seat's mounting point, using a Phillips screwdriver.


Remove the screws attaching the top of the right foot rest to the bottom of the rear fender using a Phillips screwdriver. Remove the bolt from the lower half of the foot rest using a ratchet and a socket. Pull the foot rest away from the ATV to provide clear access to the right engine crankcase cover.


Pull the rubber boot covering the reverse gear cable end, located at the rear of the right engine crankcase cover, to reveal the cable adjuster. Unscrew the cable adjuster using a combination wrench, then pull the end of the reverse cable out of the catch built into the reverse lever mechanism. Remove the bolt attaching the lever to the reverse shift actuator shaft using a ratchet. Remove the left engine crankcase cover and gasket, using a ratchet and a socket, to reveal the primary and secondary clutch assemblies.


Hold the primary clutch housing steady using a clutch holder -- Yamaha part no. 90890-01235 -- and unscrew the nut from the center of the primary with an open-ended wrench. Grasp the primary clutch housing and pull it halfway off of the primary shaft. Rotate the primary clutch until the indentation in the primary gear is aligned with the indentation in the secondary clutch housing. Pull the primary clutch carrier assembly, clutch housing and the plain washer off of the primary shaft.


Unscrew all five bolts from the secondary clutch pressure plate -- the outermost plate at the center of the secondary clutch assembly -- in a crisscross pattern using a ratchet. Pull the clutch springs out of the pressure plate spring wells, then pull the pressure plate out of the secondary clutch assembly.


Measure the uncompressed length of the clutch springs using a vernier caliper. Replace all five springs as a set if any of the springs are less than 1.54 inches long.


Slide all 13 fiber and steel clutch plates out of the secondary clutch assembly. Separate the fiber plates from the steel plates. Measure the clutch plates' thickness with a vernier caliper. Replace the clutch plates as a set if any of the fiber plates are less than 0.11 inch thick or if any of the steel plates are less than 0.008 inch thick.


Straighten the bent lockwasher tabs at the center of the secondary clutch assembly using a flat-head screwdriver. Hold the clutch assembly steady with the clutch holder tool, then unscrew the nut from the center of the secondary clutch using a breaker bar and a socket. Slide the inner clutch boss, thrust washer and the outer secondary clutch housing off of the splined secondary clutch shaft. The neutral switch will now be accessible at the upper left corner of the crankshaft.


Remove the neutral switch from the crankcase using a ratchet. Pull the neutral switch wiring grommet out of the groove cut into the crankcase. Loosen the band securing the wiring to the ATV's frame, then unplug the switch connector.


Mount the new neutral switch onto the crankcase and tighten the switch bolts to 4.3 foot-pounds using a torque wrench. Coat the switch wiring grommet with SAE 20W-40 motorcycle-grade engine oil, then push it into place against the crankcase. Route the switch wiring connector through the band and plug it into the ATV's wiring harness. Tighten the band to secure the wiring to the ATV's frame.


Slide the secondary clutch housing, thrust washer and inner clutch boss onto the secondary clutch shaft. Slip a new lockwasher over the shaft and screw the clutch nut into place. Hold the secondary clutch stationary and tighten the nut to 65 foot-pounds.


Soak the clutch plates in engine oil for one hour. Slide the plates into the secondary clutch assembly, starting with a fiber plate, followed by a steel plate. Alternate between fiber and steel plates until all 13 clutch plates have been installed.


Push the pressure plate over the clutch plates. Insert the clutch springs into the pressure plate spring wells and screw the clutch spring bolts into place. Tighten the bolts to 5.8 foot-pounds.


Slide a plain washer over the primary clutch shaft. Align the primary gear's indentation with the indentation in the secondary clutch housing, then push the primary clutch housing and clutch carrier onto the primary clutch shaft. Hold the primary clutch steady and screw the primary clutch nut into place. Tighten the nut to 100 foot-pounds.


Reinstall the right engine crankcase cover and gasket onto the engine. Tighten the crankcase cover bolts to 7.2 foot-pounds. Reinstall the reverse shift actuator lever onto the crankcase cover and tighten its bolts to 7.2 foot-pounds. Reattach the reverse cable to the lever and screw the adjuster into place. Pull the rubber boot over the end of the cable.


Reinstall the right foot rest onto the ATV. Tighten the foot rest bolt to 46 foot-pounds. Tighten the screws at the upper edge of the foot rest snugly.


Reattach the negative cable to the battery's negative terminal and tighten the terminal bolt. Reinstall the seat onto the ATV.

Items you will need


About the Author

An avid motorcyclist, Chris Gilliland has immersed himself into the two-wheeled world while balancing work life and raising three daughters. When he is not managing the parts department of a local, multi-line motorcycle dealership, Gilliland can often be found riding, writing or working on his motorcycle blog, Wingman's Garage.