I've tested mine on dirt before (front and rear) and it's obvious when it's
working (or not). It locks ever so briefly and releases and cycles between.
Do this at your own risk though and don't try it unless you are very
confident about sliding the bike. Try it at very low speed first.
If you have no joy with getting the ABS unit replaced free from Yamaha, I'd
bleed the brakes and "exercise" the ABS via the diagnostic plug under the
seat (as Jeff B says, search the archives), bleed again and exercise a
couple more times. You might actually get it to free up. Haven't heard that
anyone had success with this but it's worth a try. The good news is that
most have had the problem limited to the rear brake only and Yamaha replaced
many of our ABS units at no cost because we complained as a group. Most were
replaced in 2000 and 2001. However, it seems that recently it has become
more difficult to get Yamaha to replace it for free. Be persistent.
Below is a copy of the letter sent to Yamaha that got them to do the free
replacement. This will fill you in a little further.
Good luck,
Joe.
*********************************
Yamaha Motor Corp. USA Joe Loss
6555 Katella Ave. 2043 Mariposa Ave.
Cypress, CA 90630 Boulder, CO 80302
(303) 860 2983 (WK)
The President, (303) 448 0824 (HM)
I am writing this letter to you on behalf of a number of fellow Yamaha GTS
1000 owners concerning failure of the ABS braking systems on these
motorcycles. Through an internet discussion group for GTS enthusiasts, we
have conducted a survey showing that at least 37 discussion group GTS owners
have, or have had, ABS systems which have failed. I have documentation from
these owners giving their details and information concerning their problems
that I can send to you for your perusal. Most of these have not had the
system repaired yet due to the prohibitive cost charged by Yamaha for
replacement of the ABS hydraulic unit (HU).
This is a serious safety issue and we believe Yamaha should take immediate
action to correct the currently unacceptable and dangerous situation.
1) THE PROBLEM
We have had reports of both front and rear brake failures, however
most owners report problems with the rear brake. When the failure has
occurred, in a severe braking situation, the brakes will easily lock-up and
the ABS system does not control hydraulic pressure as it is designed to.
Moreover, the ABS malfunction warning light does not illuminate to advise of
the failure. Consequently, we have found that many owners were unaware that
their ABS had failed until they heard of other failures and tested their
units. Many owners have been riding their GTS's for many years unaware of
the fact that their ABS unit is not functioning properly or of this
potential danger.
Of course, this is a serious safety issue because ABS braking
systems are supposed to allow the operator the confidence to heavily apply
the brakes in an emergency situation without fear of lock-up. The owner of a
GTS that is not aware his ABS system has failed, may brake in an
inappropriate manner for a non-ABS brake, causing lock-up and loss of
control of his motorcycle. This will likely occur in the worst possible
situation, in an emergency. Even for owners who are aware of the failure,
learned reactions from years of ownership may cause over-application of
brakes resulting in lock-up.
We have no documented evidence of any accidents caused by this
failure, but we are trying to obtain any relevant accident information at
this time.
2) EXTENT OF PROBLEM
We have at least 37 documented cases of GTS 1000 ABS brake failures.
In most cases I have collected signed forms completed by the owners with the
following information:
Name / Address / Phone number:
Model / Year:
VIN number:
Current mileage:
Failure (front/rear brake):
Mileage at which failure first detected:
ABS Repairs performed and cost:
Repairs completed under warranty (yes/no):
Comments:
Signature / Date:
I will gladly forward you this information upon request.
Considering the small number of GTSs produced (approximately 800 in
the United States) the number of reported cases of the failure is very high.
This is particularly true given that only a small percentage of all owners
have been surveyed. We believe this ABS brake defect to be a widespread
problem with this model Yamaha.
3) THE CAUSE
The general consensus of opinion among GTS owners is that the
problem is caused by corrosion of the HU components through moisture and/or
air in the hydraulic fluid. One owner, after thoroughly rebuilding the HU at
his own expense, came to the same conclusion. Most owners report having
changed brake fluid regularly, some as often as every 6 months.
Nevertheless, ABS failures still occur.
Many owners believe the ABS system is abnormally susceptible to
leaks allowing air and moisture to enter the system. They also believe that
HU components are abnormally prone to damage from deteriorated fluids. A
number of owners suspect that regular "exercising" of the HU through
invoking ABS diagnostics is important to flush old fluid out of the HU
before it becomes severely contaminated. Regular bleeding of brakes alone
may not renew this trapped fluid. However, even if all these precautions are
taken, the ABS units continue to fail.
4) OWNER'S MANUAL MAINTENANCE RECOMMENDATIONS
If the GTS ABS system was designed to require abnormally frequent
brake fluid changes and regular "exercising" of the HU, many owners are
curious as to why the Owner's Manual supplied with the motorcycle or the
Shop Manual do not clearly state these procedures.
In fact, the Owner's Manual does not even list replacement of brake
fluid in the recommended maintenance schedule. Incredibly, nowhere is it
stated that replacement of brake fluid is ever required. Further, the Shop
Manual states the fluid should be replaced "only when brakes are
disassembled".
5) CURRENT REPAIR PROCEDURE
Some owners have requested that Yamaha repair their malfunctioning
ABS units. However, Yamaha has refused to repair the HUs and has insisted on
replacing the entire HU at a cost of about $2000. Some owners have had HUs
replaced under warranty, others have borne the cost on their own. We believe
that requiring non-warranty owners replace the defective HU's at such a
prohibitive cost is an unacceptable situation. Particularly since we believe
that replacement of the HU's alone does not remedy the problem in the long
term.
A few mechanically competent owners have attempted reconditioning
HUs on their own and at their own expense. Some have been successful, some
have not.
6) YAMAHA ABS SYSTEM DESIGN
We are not aware of other motorcycle or car manufacturers having
widespread problems with their ABS systems as is evident on Yamaha's system.
If other manufacturers can produce reliable systems then it is not
unreasonable to expect that Yamaha should do the same.
Most GTS owners bought their bikes, in part, because of the added
feature of ABS brakes. It is unfair to expect owners to pay exorbitant costs
for maintenance of a flawed design, or to simply do without their ABS system
for which they paid a premium at time of purchase.
7) WHAT YAMAHA SHOULD DO
We are a group of GTS enthusiasts and most of us have previously owned many
Yamahas. We all want to continue to purchase Yamaha motorcycles. We believe
Yamaha should immediately address this ABS failure problem to restore our
confidence in Yamaha's commitment to its products.
We believe Yamaha should further investigate the ABS system problem to
determine the exact cause and the best possible repair or modification to
ensure long term reliability. For those units that have failed, Yamaha
should carry out these repairs and modifications at no cost to the owner.
If necessary, based on Yamaha's investigation, Yamaha should also issue to
all current owners and all Yamaha dealer workshops an addendum to the
Owner's and Shop Manuals with more detailed and updated recommended
maintenance for the braking systems.
We look forward to receiving a prompt response to this letter in the very
near future. Please feel free to call me directly to discuss any aspect of
this issue.
Regards,
Joe Loss.
-----Original Message-----
From: Boman, Jeff [mailto:[EMAIL PROTECTED]]
Sent: Monday, October 14, 2002 2:14 PM
To: [EMAIL PROTECTED]
Subject: Re: ABS System Not Working Properly, Please Help
Dan,
First, Take a ride down the archive trail to learn how to activate the ABS
while sitting on the center stand.
Secondly, the dirt road scenario may be influencing the ABS. I can't
remember anyone else attempting to test the ABS system on a dirt road. You
might want to try firmly applying the rear brake in a simulated panic mode
on a solid surface and see what happens. I recommend the rear break only,
because I haven't found the ability to truly apply the front brake hard
enough to make the bike do anything other than stop quickly.
Jeff B.
======================================================================================
NOTICE - This communication may contain confidential and privileged information that
is for the sole use of the intended recipient. Any viewing, copying or distribution
of, or reliance on this message by unintended recipients is strictly prohibited. If
you have received this message in error, please notify us immediately by replying to
the message and deleting it from your computer.
==============================================================================
