Date: Thu, 30 Oct 1997 18:30:41 -0800 From: "D.R. McClellan" To: gts-1000@MBnet.MB.CA Subject: Wobbly Alignment Explanation MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Hey Rich! Thanks for the good info. Now that you've go the front aligned but scary, check to see if it was compensating for a poorly aligned rear. I had a front tire wear on the left side last summer, and the problem magically went away when I put on a new rear. So I think I was riding around with the rear tire misaligned. The marks on the rear swingarm are usually reliable, but not always. There are tools available that make the check a snap. Basically it's a long straight edge with long threaded pins that contact the edges of your rims. (Lame ASCII Art follows) | | __|_____|____________|_______|__ The front and rear rims differ in width so the pins need to be adjustable, and you have to have the pins long enough to clear the centerstand. The pins that contact the front wheel need to be adjusted to EQUAL lengths(distance from straight edge to pin tip) but LONGER than the ones for the rear which should also be at EQUAL lengths. You should be able to get all four pins to contact the rims at the same time. Once you've achieved this, and without moving the steering, or adjusting the tool, try to get the same contact on the other side of the bike. If this can be done, and you can move the tool to different heights on the wheels, then the front and rear wheels are operating in parallel axes along the same plane. This is what you're shooting for. Lockhart used to sell these for a chunk of change. A friend made one out of a cheap iron bed frame and some long screws that he put points on. You figure out how to make sure it's straight. What's it all about? The front wheel will automatically try to compensate for the rear, and the result is that the axes will be parallel, but the two wheel will be operating in different planes. When weight shifts, this leads to a tilt which (through the forces of gyroscopic precession) leads to another adjustment of the front wheel. This is your wobble on deceleration. It doesn't usually show up on acceleration, because the rider is busy and aggressively controlling the bike. This problem is slightly more involved on the GTS in that we can control our camber settings instead of being stuck with the results of a bent frame. This is why it's important to check at different heights along the wheels. Granted you can probably only move the thing an inch or two. Hope this helps. - o - / = > Later, - (_)==(_) Don ---------- > From: Rich Simmons > To: gts-1000@mbnet.mb.ca > Subject: Wobble and Camber > Date: Sunday, October 26, 1997 1:46 PM > > In the past I have commented about my front tire wearing a lot more on > the left side, and also looking as if it was "tilted" to the left. I > am also one who has never experienced a wobble of any kind. Well I > ordered a service manual from Pacific Yamaha ($92.95 Canadian with > shipping) so that I could adjust the camber to eliminate my front tire > wear problem. > > I set up to do the camber adjustment according to the manual. The first > thing I found was that my front wheel was at "the Standard Setting" 2 > turns out. > > I went about following the manual to set the camber. To get mine set > according to the manual, I needed 4 turns out. Quite a bit different > than the standard setting. > > I reassmebled everything, The front wheel now looked straight, the > tilting to the left gone. Everything was perfect until the test ride!!! > > The bike handled fine, fast, slow, corners, until I took my hands off > the handle bars about 70. At 65 or so slowing down I got a severe head > shake and wobble until I slowed below 55. I now have the wobble that so > many of have complained about at the same speed !!! > > Do you think its possible Yamaha knows this and thats why the standard > camber setting is what it is to eliminate the wobble?? My bike was a > factory demo bike with 4k miles on it when I purchased. > > I am going to ride it some and see which worse, the tire wear or the > wobble. If I keep my hands on the bars I feel no hint of wobble. > > Rich Simmons > Fort Worth TX ------------------------------ Sounds like a system that takes alot of time. Should be very precise. I use a 6" ruler to measure the exact distance between the swingarm, and the chain tensioning bolt. The ruler I use is a 6" steel rule with marks for every 64th of an inch. As of yet no wobble. (I also have not checked the front, but both sides of the tire wear the same.) I recomend keeping this ruler on the bike at all times, I have found more uses for it than any other single tool when it comes time to adjust something (chain tension, tire tread depth, etc). Louis