The Yamaha Vstar 1100 Starter


External bolts This is what we are looking for,  the incidence of defective VStar 1100 starters as defined by twisted external bolts.  This starter was removed from the motorcycle, but the twisted bolts could clearly be  identified whether the starter was removed or still mounted in place.  Please refer to the captions in this picture for definitions used in this discussion
  1. Rear end cover - This is the part of the starter motor that is bolted to the engine block by two bolts (not shown)
  2. Starter barrel - The permanent field magnets of the motor are attached to the inside of this barrel.  The armature shaft is supported by a plain bushing inside the rear end cover and its field windings are energized through four brushes mounted to a base plate located under the rear end cover.
  3. Front end cover-  The torque is transmitted and multiplied by planetary gears located under this cover.
For the purpose of identifying the defect, we will use the criteria of "twisted bolts" as shown in the picture above.  We will look at a few pictures of the internal parts of this starter, and a few other examples of defective starters, to see what elements of the design failed.  These internal details will be provided for clarification, but it is important to note that the twisted bolts are by themselves enough to identify a starter as defective.  As we shall see, the external bolts can not be twisted unless some vital internal structural elements of the starter's design have failed.  It will be clear that even though the failure is identified by the twisted bolts, the bolts can not be twisted unless serious internal damage has also taken place.  

Before we look inside the starter, let's look at a few more external clues.

Alignment Marks

Alignment marks
The  Vstar XVS1100 Service manual  (part number LIT-11616-12-63) on page 7-21 references these alignment marks.  They are to be aligned as stated in the note at the bottom of that page.  To quote:

"Note: Align the projection (a) with the slot (b) on the end cover and starter motor yoke"


Clearly the alignment mark on the starter barrel is not aligned with the projection on the end cover.   Something is wrong with this picture.  The starter is twisted as initially noted by our external observation of twisted bolts, but closer examination shows the factory alignment marks to be off by an approximately equal amount.  Determination of a twisted starter doesn't require removal from the bike.  It is very easy to assess the situation with the starter still installed on the bike as these pictures show.

 


Notice that the bolts are not in alignment with the engine using the front engine mount bolt as a reference point.  Examples like these should be listed as "twisted" in the following survey 

 

As a contrast, the next picture shows a normal starter.  Notice that the starter bolts are aligned with the front edge of the engine block.  It is clear that this starter is not twisted, but aligned squarely with the engine block.  If your starter looks like this, we need to hear from you too.

 

 

One of the pieces of information that will be needed is the date of manufacture which is found on the Vehicle Identification Number sticker on the left front frame down tube.  Although it is barely visible in this picture, the date of manufacture is printed in large numbers in MM -YY format.  The date of manufacture of this bike is 4-99.  Please take a moment to determine the date of manufacture and dates (if any) of any relevant service done to the bike.  After taking the survey, come back and read more about the details about what goes on inside the Yamaha starter.  Once again, we need people to respond to this survey regardless of the condition of their starter.

 

Please fill out the survey form and send it along to us so we can collect the data into a meaningful report.  We would like to demonstrate to Yamaha Corporation that they would be acting in their own best interest by addressing the problem and developing a cure.  We need hard data, not just a few isolated instances.  We also don't need you to take your bikes apart to help out.  A simple external examination of your bike is all that is needed.

Thank You

Proceed to Questionnaire       Top of Page        Continue Reading