The Yamaha Vstar 1100 Starter -
Internals
Drive End Cover - Dowel Pin
Lets take a look inside the starter
This is a close-up of the inside of the front end cover. Note that
the dowel pin is intact and not broken or damaged and is located in its
proper place . Notice also the raised projection barely visible above the
top edge of the cover. This is the "projection" that is supposed to be aligned
with the mark specified in the manual page 7-21 and pictured above in this
report. Everything here looks as it should. The dowel pin is where it should
be. Nothing is damaged and the locating pin is in the specified location.
What then is the reason for the misaligned parts as shown by the twisted
bolts and the improper alignment of the marks shown in the above picture?
Lets take a look at the other half of this mating surface, the starter
body where it aligns and mates with this end cover.
Planetary Gear
The dowel slot shown here on the outer perimeter of the planetary gear is the locking point for the dowel pin shown
in the previous picture. It is obviously in fine shape and able to solidly lock the body of the starter, and the planetary gear to
the front end cap as designed and as noted in the service manual (page
7-21). This hard steel planetary gear is a semi-loose fit into the
softer metal outer shell of the starter body and is locked in position solely by the single
dowel pin.
We can see that the dowel pin shown in the previous picture is correctly
located and not damaged. We can also see in the picture to the right,
that the dowel slot is not deformed. How is it then that the alignment
marks are so far off ?
It
can get very complicated at this point so we will simply say that the drive end
is locked in place by the dowel pin, which appears to be doing the job.
There are several "locking detents" as pictured that are stamped into
the side of the starter body, apparently to keep other internal parts from
turning such as the field magnets from turning. However, we aren't going
to look inside there just yet. There is some reason that the major components of
the starter are twisting relative to each other and it isn't the dowel pin at
the drive end that failed in this case. Maybe the answer is at the other
end of this starter.
Rear End Cover - Brush Assembly Base Plate
The rear end cover is removed revealing the brush assembly base plate.
Pay close attention to the locking tab on the brush assembly base
plate, and on the raised bumps inside the rear end cover. The general condition of the brushes and the other
wear items indicate that the starter on this bike was not abused and does
not have many miles on it. There is no discoloration to indicate an overheating
condition. I was amazed
by the pristine condition and lack of general wear of the internal parts
of this starter.
Everything seemed almost too perfect. What's wrong with this picture?
We know that this starter is defective as defined by twisted bolts. We saw
that the alignment marks were off by the same amount. Something had to
have failed, and it wasn't the dowel pin Maybe the problem is to be
found under the brush end of the starter. A closer examination
of the parts at this end of the motor soon revealed a problem Let's zoom in for more
detail.
Brush Assembly Locking Tab - Close-up
The close-up of this locking tab is almost frightening. All of the torque
of the starter is resisted by this one solitary bent piece of soft metal.
We saw how the drive end of the starter is held in place by a solid
steel dowel pin locking the barrel of the starter to the front end cap.
However, the starter is bolted to the engine at the other end of the
starter motor. All of the twisting of the motor, and all of the hammering
of the occasional engine kickback is ultimately focused on this puny little
tab of mild steel. Although this picture doesn't clearly show it,
the tab was actually bent so far back and toward the inside, that
it was able to bypass the raised bump molded into the rear end cover.
Every time the starter was engaged, the free play that was worn into the
parts shown here allowed the parts to slam into that tab. Is there
any wonder that there was often an audible "klunk" when this happened?
Maybe this starter was a fluke. Maybe this was a freak occurrence
and maybe nobody else would have this problem. I guess we need to
look at a few more samples then.
Another Example - Higher Mileage Starter
Does this look familiar?
This starter obviously has more mileage on it as indicated by the amount
of oxidation on the commutator, and by the wear on the brushes. The tab
is bent back into a total state of submission as was the locking tab in
the previous example.
Maybe a top view will show a different perspective.
The top view shows the tab bent inwards allowing enough room for the end
cap to twist without obstruction.
I looked at the drive end of this particular starter. Things got
ugly
Remember the dowel pin shown in the previous lower mileage starter? Apparently,
this starter got hammered and pounded enough that the dowel pin gave up
and sheared off. If you look closely you will notice the broken stub
end of the broken dowel pin still in the hole in the front end cap.
Can you imagine the banging and clanging that took place when this starter
was kicked over? This little cranker was loose and sloppy at both
ends of the motor!
This is the only example I have seen of this type of failure, but we would
be interested to see if there are any more out there that look like this.
Here's a picture of both parts of this sad case. Note especially
the broken pieces of dowel lying on the bench in front of the starter
parts (circled).
Once again, it is important to remember that the internal broken parts
bring more depth and understanding to the discussion, but we don't need
to go to this detail to establish the defective starter. All we are
trying to do is to determine the number of occurrences of defective starters. The determination of failure needn't
require the dismantling of starters. All we need is to determine the
extent of the problem as noted from strictly external visual clues. It is also
very important that we hear from as many Vstar 1100 owners as possible, whether
or not you have a problem.
That was kind of a long way around the issue, but we want you to have a
clearer understanding of the inner workings of the starter motor to better
understand why the twisted bolt syndrome is not an insignificant issue. It
is symptomatic of a serious internal breakdown of the parts.
This is all we are looking for. Notice the long bolts in the picture
to the right. They are obviously twisted. There is no need to
take things apart to prove that the internal parts are broken or bent. As
we have shown, it
can be proven logically that if the external bolts are twisted, the internal
parts must also be damaged.
If you have not yet done so, please participate in the poll regardless of whether or not your bike has the
symptom. We need to hear from all owners of the 1100 Vstar. At this time, all we are doing is trying
to establish whether or not a problem exists, and whether or not it exists on a large
enough scale to expect Yamaha to address the issue.
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