MOTORCYCLE 6/2/10 M2010-009

All XVS11 ModelsNew Starter One-Way Bearing Parts

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©2010 YAMAHA MOTOR CORPORATION, U.S.A.

If you encounter an XVS11 customer that has experienced a Starter One-Way Bearing failure; in addition to replacing the damaged components, the root cause for the failure needs to be addressed. Typically, these failures are caused by engine kickback during starting. Listed below are some common causes of engine kickback during starting along with their respective corrective actions:

Common Kickback Causes Explanation and Corrective Actions

Incorrect starting procedure.

Applying throttle while starting is probably the most common cause for starter one-way bearing failures. Customer education is key.Cold Engine: Apply full choke and DO NOT apply any throttle while crank-ing the engine.Warm Engine: No choke and crank the engine but DO NOT apply any throttle.In either of the above starting conditions, if the throttle is applied while cranking the engine, an extremely lean fuel mixture is created. This lean condition is very volatile and can result in very abrupt combustion causing the engine to rotate backwards violently, damaging the starter one-way bearing and possibly other starter system components.Inform your customers about the correct starting procedures.

Carburetor mixture is too lean.

A tell-tale sign of lean carburetor settings are “blued” exhaust pipes. The blued exhaust pipes are the result of a customer operating the vehicle with the choke on for an extended period to overcome the engine hesita-tion caused by the lean low speed mixture setting. As mentioned above, lean settings can cause engine kickback.Aftermarket exhaust and or open intake with stock jetting can also con-tribute.Adjust the carburetor mixture screws to provide the correct CO (1.5 %).

Stale fuel or varnished jets present.

A common theme here is lean fuel mixtures. Stale fuel often leads to hard starting causing the customer to crank the engine longer than usual. This increases the chance of the customer opening the throttle while the engine is cranking causing an extremely lean condition.Partially clogged jets cause lean fuel mixtures.Clean the carburetors and install fresh fuel.

Intake air leak is present.Intake air leaks create a lean condition.Confirm that no intake air leaks are present. Repair as needed.

Other Contributing Factors

Battery in low state of charge. Fully charge the battery.

Idle speed is too low. Adjust the idle speed (950 ~ 1050 rpm).

Carburetor synchronization is incorrect. Synchronize the carburetors.

Addressing the root cause for a starter one-way bearing failure will drastically reduce the possibility of engine kickback during starting. However, in the event that one of the above conditions should occur in the future, a new Starter Damper Assembly has been developed that will help minimize starter system wear during kickback. This new Starter Damper Assembly replaces the original idler gears and shaft and is supported on either end by needle bearings which will need to be installed into the crankcase and crankcase cover prior to installing the new damper assembly.

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Refer to the Service Manual for repair procedures along with the following steps:

IMPORTANT: Use Technical Bulletin M2009-007 for time saving tips and detailed instructions for generator rotor removal and rear cylinder cam timing.

Needle Bearing Installation:Crankcase:Place a rag over all crankcase cavities to avoid debris or dropped parts from entering the engine.

Crankcase Cover:Using some soft rags to protect the outer finish of the crankcase cover, properly support the cover for bearing installation.

Be sure to use a suitable bearing driver to install the bearings into the crankcase and cover. Locate the original starter idler gear shaft boss and square up the bearing to the boss surface. Carefully install the bearing into the boss until it is flush with the boss outer surface.

Lubricate the bearing with engine oil.

DRIVER

BEARING

SHAFT BOSS

CRANKCASE OR COVER

STARTER DAMPER

ASSY

STARTER MOTOR

STARTER MOTORNEW PARTS

SUPPORT BEARING

SUPPORT BEARING

IDLER GEAR 1

ORIGINAL PARTS

IDLER GEAR 3

SHAFT

STARTER ONE-WAY ASSY.

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NEW STARTER DAMPER ASSEMBLY

*= INCLUDED IN THE KIT

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For your convenience, a Starter One-Way Repair Kit has been created. The original starter one-way bearing part number will automatically supersede to this part number.

Original Part Number New Kit Part Number Description Qty

5EL-15590-00-00 99999-03908-00 Starter One-Way Assembly 1

The kit includes the following parts:Part Number Description Qty

3B8-15590-09-00 Starter One-Way Assembly 1

5EL-15517-11-00 Gear, Idler 2 1

5EL-15451-00-00 Gasket, Crankcase 1

93102-12321-00 Oil, Seal, SD-type 1

3B8-15560-09-00 Damper Assembly (New Parts) 1

3B8-15115-09-00 Bearing (New Parts) 2

Provided by YAMAHA OF CUCAMONGA - All Rights Reserved