Peter, I thank you for your good wishes and advice. I'll be sure to have my mechanic check out the front caliper when he is getting to the bottom of why I experienced the problem that I did. Better yet, after I notify Yamaha corporate about my experience, perhaps they will have one of their experts look into the problem. I do know that no one is going to be able to determine the cause of the failure until they have personally inspected the motorcycle. My first hand experience with the maintenance history/mechanical condition of my motorcycle and the sequence of events during my incident make me 100% positive that the ABS system and not the caliper was the culprit. If I am proven wrong when the caliper is inspected, I will gladly eat my helmet. :^)
I know you weren't attacking my service guy in your post, but for the record, in all of my dealings with him he has proven to be an extremely competent mechanic and technician (this has NOT been my experience with all Yamaha mechanics). He was very thorough at the time that he replaced my ABS pump. I know this because I assisted him during the entire procedure (o.k., he let me stand there next to him while he did the work and I held stuff for him from time to time). :^) He inspected the entire brake system during the procedure including the calipers and he declared the system to be in excellent health. I especially remember him telling me and showing me that the calipers were in excellent condition because I had asked him about them specifically. I had asked him about the calipers for a very good reason. Before I had the ABS pump replaced, I had written the GTS list about my rear wheel locking up (I was too chicken to test the front brake at that time. I wish I had been too chicken this past Saturday). In response to that post, someone had written me back suggesting that the rear caliper was sticking. The calipers were not sticking then and I do not suspect that they are sticking now. Also, least anyone misunderstand, I am fully versed in the operating theory involved with an anti-lock braking system. I fully understand that "the HU is designed not to interfere with normal braking action when it has even the slightest problem". Unfortunately, the GTS ABS system is apparently not very proficient at determining when there is a problem. To add insult to injury (no pun intended), it won't even acknowledge when it has failed and one of the wheels has actually locked up. Maybe if I can get both wheels to lock up at the same time one day, that darn ABS fault light will finally activate. :^) The incident I experienced this weekend happened over the span of a second or so. The ABS system did activate and try to release brake pressure as indicated by the lever dropping back toward the bar. Things were happening very quickly, but it did seem that after the lever dropped back towards the bar that the front brake did release slightly before it went into full lockdown mode. That brief moment of ABS malfunction delayed my reaction time just long enough to put me into a near unrecoverable position. Safely recovering from a locked front wheel on any motorcycle is hard enough without a malfunctioning ABS system screwing with things at the same time. Again, I'll eat my helmet if a malfunctioning front caliper had anything to do with it. In fact, I'll also eat my red white and blue Elvis racing boots, too. :^) Shawn, Thanks for the good wishes, I'll be sure to follow your recuperative advise. Sorry to hear about the problems that you are having with your front caliper. Man, what kind of roads do you drive on? After seeing your post I actually went out and looked at the front end of my motorcycle to try and figure out how rocks could have hit your brake pistons. With the caliper nestled inside the front wheel like it is that looks like it would be very difficult to happen. You haven't been off-roading on your GTS have you? :^) I have skinned the tires and performed the routine brake maintenance on all of my motorcycles for many years. During each of those occasions with the GTS I have always cleaned and inspected the brake calipers as thoroughly as I could without completely disassembling them and everything has always appeared to be in excellent condition (the last time I did this was less than 3,000 miles ago). Functionally, the regular brake system (excluding the ABS) has never given any indication of a problem. My goodness, my GTS has rarely ever been ridden in the rain, it has never been ridden down a dirt road, it's only got 18,000 miles on the clock, and it is always parked in an enclosed garage when it is at home. I can assure you that with the high level of care and attention this motorcycle has experienced, something like a seizing brake caliper would not have escaped my attention. I should point out that I have never had the ABS activate during a real emergency braking situation except for the rare occasional flutter of the back portion of the system during maximum weight transfer to the front wheel. The most excellent regular braking attributes of the GTS have never required me to cross over the ABS threshold on the front end. Thanks to all and I will keep you posted as I find out more. Duane ----- Original Message ----- From: "mototune" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, February 26, 2002 8:36 AM Subject: Re: WARNING: Road Test Your Front Anti-Lock Brakes at Your Own Peril ----- Original Message ----- From: "Shawn Pearsall" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, February 26, 2002 11:53 AM Subject: ABS Front Caliper
