| Author | Message | ||
     Bradj |
Yesterday, while "aggressively" braking the XB9SL in a straight line, on clean and dry pavement, the bike felt as if it was becoming unstable. It did this twice and frankly, scared me.  I'm not talking an emergency stop from 80 MPH here...I'm talking "Hey... I'm about to enter this curve at 55-60 MPH and I really want to get down to 40-45 before I lean it" kind of braking. I have been cruising the Knowledge Vault and there were numerous posts on what I thought was a similar occurence...referred to as "pulsing" with possible explanations being a warped rotor or wheel runout. There was also a reference to a change in rotor mounting assemblies at the factory. The bike is a 2003 XB9SL with 2150 miles on it...still on the original front tire [no wear indicators showing]. The suspension settings are out of the book for my weight. My experience is rather limited, but it appears that this is similar to what others have reported. Am I doing something wrong...like not enough, or too much rear brake...that is contributing to this? I have rarely had the bike over 70 MPH and/or 4000 RPM so I certainly don't think I'm pushing the envelope that damn hard!  | ||
| Hans |
Once you have pressure is on your front tire, any rear braking is too much. Hans | ||
| Frankenstein |
Bradj, Have you recently washed your bike (and the brakes) with something like S100 cleaner? If so you should not get that stuff on the break discs. Never had that on the XB but another bike of mine did the same thing after I got S100 cleaner on the discs. The cure was 3 or 4 hard stops from 70 mph to get the brakes hot. After that the oscillation was gone. Far fetched but you never know. Hope this helps! | ||
| Stoobr2 |
Bradj...... try running you hand anti-clockwise (opposite direction to the rotation) up the front tyre,you might feel some stepping on the tread having covered 2150mls ? on the OE 207's ? this might/will affect the handling of you XB. Even though the front tyre may look fresh & have plenty of wear left,it does'nt necessarily mean it will still give "optimum" performance,especially under braking. Try having the headrace bearings checked aswell,they may have "settled" since they were fitted & may need adjusting. edited by StooBr2 on February 23, 2004 | ||
| Reepicheep |
If you have a really bent rotor / wheel, you will feel excessive travel of the front brake lever. All rotors have some runout, and indeed that is what the system depends on to get the pistons back in the calipers when the brakes are released. If the warping is bad (like say for example Tri County Harley Davidison in Cincinnati mangles your rotor while mounting a tire), you will find it takes much more lever travel (like two full pumps) to get braking pressure up. If you were a little more specific about the "instability" we could probably be of more help. | ||
| Stoobr2 |
I just remembered that "Trojan" reported a simular sort of thing on his XB race bike here in the UK. The problem turned out to be the clamp bolts on the yokes,so the forks were slightly loose!!!! | ||
| Trojan |
Not just us either, I've heard that from a couple of people too. It isn't the clamp bolts on the yokes though, it's the pinch bolts at the bottom of the fork leg that come loose. | ||
| Bradj |
By "instability"... I meant that the front end/handlebars started wobbling and it felt like I was about to lose control of the bike... Perhaps you could call it a "head shake under braking"? I didn't notice anything weird going on in the brake handle, but honestly I was so "rattled" by the event I probably missed the more subtle nuances...  Here are some more specifics that might help.... Front tire was at 36 psi...checked before I started my ride. Suspension setting per the manual for my weight. I haven't had a wreck and don't recall hitting any potholes or obstacles. The only time the bike has been ridden on gravel was for 1/4 mile, later in the day following the wobbling episodes. The bike has fallen over [slowly] twice...once in a parking lot and once on my trailer...both times while sitting still.  I did have to replace the hand brake control lever, but the brake appears to have been functioning normally, otherwise. I DO use the rear brake in conjunction with the front brake... every time I brake. I have read some postings here that suggest that I shouldn't be doing that....?  This seems contrary to the "conventional wisdom" I have been taught. Remember...I'm a fairly new rider, here.  As always, I appreciate the input. I haven't discussed this with a dealer yet. I was hoping to get a little educated so as to better "guide" them to a possible cause. I've heard you have to do that...sometimes.  | ||
| Stoobr2 |
Sorry Matt, I stand corrected  | ||
| Stoobr2 |
Brad..... Try checking the headrace bearings & wheel bearings. | ||
| Reepicheep |
Any clunking from the front end when the front brakes are applied while in motion? | ||
| M1combat |
Yeah, I would go after the bearings and pinch bolts. Were you entering the corner with any brakes or was all of this in a straight line? | ||
| M1combat |
The XB has very little rake and trail. This doesn't make the bike unstable as such, but it does mean that the bike is VERY sensitive to rider input. Also, because the bike is short it is also very sensitive to rider position. Could either of these have been a factor? | ||
| Stoobr2 |
Maybe it was an "uneven/rippled road surface ? Their are quite a few "possibilitys" you just have to rule them out by checking 1 thing at a time Brad. | ||
| Hans |
"I DO use the rear brake in conjunction with the front brake... every time I brake. I have read some postings here that suggest that I shouldn't be doing that....? This seems contrary to the "conventional wisdom" I have been taught." Yeaaaaah, I see in your profile: "It reminds me of my John Deere tractor" It is definitely not a John Deere tractor. It is so easy to lift your rear wheel from the ground: Try to forget the rear brake completely for a while.  Hans | ||
| Xb9er |
Has this situation come up before and you haven't had the "headshake" or wobble? If so, was it before or after the bike was dropped? Following up on what M1combat said, the XB's are sensitive for the reasons given. By your own admission you were scared so a natural response could have been to tighten up your grip and lock your elbows. This, along with use of the rear brake at that point, will upset the front end stability. Have you taken the MSF Basic Riding course? If not, sign up as soon as you can. Practice your braking in a parking lot using only the front brake and get used to that. I agree with Hans that in the situations described you were using too much rear brake. YMMV Mike. | ||
| M1combat |
IF the problem was induced by rider input... Try to stay to the rear under braking. Grip the frame with your knees and do NOT stiffen your arms. Were you downshifting at the time? If so you may have been breaking the rear tire loose a tad with the engine break used in conjunction with your rear brake. More later, I need to deliver a system to Dev. services  . | ||
| Bradj |
Thanks, I'll make some rider "adjustments" first and see if anything changes. Had the MSF...that's where I was told to ALWAYS use both brakes  . I have managed to skid the rear wheel on a couple of occasions, but I attributed that to it being a new tire on cold pavement that wasn't the cleanest. Which came first...the scare or the wobble? I don't recall being too concerned about the situation until I applied the brakes. Maybe I am slamming the rear so hard, the bike was trying to skid? Well...the episodes occurred AFTER the bike fell over, but making a connection is a bit difficult...that was several months ago. Perhaps it has been an issue all along and I am just now discovering it because I am riding bit harder? When I first got the bike I practiced some 30-35 MPH quick stops and didn't notice anything unusual...other then how well the brakes worked! Thanks again...I'm taking notes on possible causes, and if it turns out not to be operator induced, I have a good list of things for the dealer to check. | ||
| Bradj |
ooops...I got behind...missed some questions. No clunking was heard. I was braking in a straight line both times. [I thought you weren't supposed to brake in curves, anyway?] I may have been downshifting at the time...I'm not sure. I usually try to get any downshifting done well before I enter a curve. The pavement could have been irregular...rural mountain road... don't know what they call the suface...I call it "white asphalt" rougher texture than black top or concrete. As far as rider position...I wasn't aware there was much option on an XB9S Low  | ||
| Stoobr2 |
Nowt wrong with using "abit" of rear brake 1st,before applying the front,by doing this the bike will "squat" at the rear and apply more force on the tyre so it won't lock-up/skid (in theory). As for braking in corners,I have found,that my XB wants to "stand-up" the minute the front brake is applied whilst cranked over! so I found it's best to get the braking over and done with before the corner & trust yer tyres. If you find you've gone to fast/deep into a corner,try "dabbing" the rear brake to scrub off some speed & bring the front into line.It does'nt hurt to hang off the seat abit either Either or all of the above might/might not work for your riding style.It's proberly best to experiment,on a favorite corner/carpark untill you find a "happy" medium,then hopefully as you confidence bulids and you learn to trust the bike/tyres,the rest will come naturally. | ||
| Azfirebolt |
Brad, I believe I know exactly what you are talking about. My thoughts, are the oem tires and a wear point/road grime on the pads. My '04 12 with 9000 miles now, will shutter every now and then, especially when they(pads and rotor) get HOT!!! | ||
| M1combat |
Yeah, I think I'm going to go for uneven pavement but it doesn't seem to affect my 12R too much in a straight line. The only times I've been a little nervous has been entering a corner with the brakes on a little (and I've found that as PROPERLY as "I" can hang off pretty much solves that). I never use the rear unless I'm going pretty slow already. That's more habit from the great "WD-40 in the rear drum" incident on my dirt bike a long time ago. I haven't ever HAD to "scrub speed or wreck", but I've wanted to slow down a bit so I wouldn't exceed my comfortable lean angle. I learned quickly though that if I just trust the stupid bike it'll do a LOT more than I can (especially when hanging off properly (Read "Total Control" by Lee Parks, "Twist of the Wrist I & II" by Keith Code). I've kept up with GSXR's that are getting loose to stay in front of me and never even began to feel like I was near the limit (and this is on the stock tires). I don't think I've ever had it far enough over that I could even stick my leg out and TRY to touch pavement... Sure, they walk the $%^& away when we get to a decent length straight, but I always catch back up in a couple corners w/o even really trying. I guess if it was my bike and I couldn't pin it on rider error for certain I would check the tightness of ALL the bolts that have anything to do with the forks, brakes and triple tree's, and I would check the point where the swingarm mounts to the gearbox (that huge rubber thing...). Also, make SURE that the bike is indeed set up to the factory settings for your weight (make sure you didn't start from the wrong end or confuse rebound/compression etc...). After that I would go try it again in the same exact spots (BUT DO NOT TIGHTEN UP YOUR UPPER BODY, GRIP WITH THE LEGS). That's my 2c anyway and I'm certainly NOT anything like a pro. If you feel more comfortable having the dealership look at it, do that . | ||
| M1combat |
I wouldn't doubt that either Greg... I would imagine that having a larger rotor would make it more likely to have uneven temps at different places around the rotor. This could offer different brake levels as the tire rotates. Who knows really. I would certainly check everything though. | ||
| Azfirebolt |
anyone ever notice how much shit gets flung by the front tire? Lots of sandish gravel on the roads here. And being anal about my bike, I find I really only have to clean the magnesium colored portion of the nose cone. It always has a black streak of shit. Imagine what the pads and rotor see. That oem tire is renowned for "cupping". I just put Pilot Sports on. Much better ride! Have a new set of pads to put on. I'll give an update if the weather clears. First day I haven't ridden in months. Pouring down buckets since 1:30 am... | ||
| M1combat |
Lots O rain up here too Greg... Well that and SNOW ... I just picked up a KLR600 that needs most of a rebuild. When I get it done I'll have to wait until next year to test it in the snow. If you want you're welcome to come up and give it a spin when I do get it done. I pretty much got it for me and my riding buddies up here to beat on but you're welcome to check it out too. | ||
| Charlieboy6649 |
Brad, Just wanted to chime in about braking. Keep this in mind. What you were taught in the MSF course is exactly RIGHT. In the course they taught you about safe point A to point B riding largely in urban areas. Not riding styles that are going to get you through that corner the fastest... You're a new rider (Like ME) and should stick to "conventional wisdom" as you mentioned for a while. Try these advanced braking techniques mentioned before they are honed, and you may find yourself in trouble in a corner because you did not set your speed before entering. I'd say have your dealer look for the problem, ride safe for now, and hone your braking skills on a track day when someone can give you pointers "on site". It's much better than road rash and a busted up bike. Some of us are new, guys, and shouldn't be encouraged before our time... "Take it from me." Charles edited by charlieboy6649 on February 23, 2004 | ||
| Marc_340 |
O.k. my xb do that kind of feeling in the front brake that feel like a bent rotor after is break in so around 1200miles after the first real ride that a push the bike to my limit.for me it was just the pad that match the rotor because it never do it again.and for the limit of the bike i waiting to find it. | ||
| Jasonblue |
I was wondering about the performance of my front breaks. When XB's first came out I had always heard how easy it was to do a stoppy on one. Now I really don't care to do a stoppy, sure it looks cool and all but I have no desire to be perched up on my front tire. See, I have had to nail my front breaks a couple times and my rear end has never come close to coming off the ground. However, I have never had any complaints about the performance of my breaks. I have since even tried a couple stoppies (starting off with minimal pressure and building to max pressure) and my rear tire has not come off the ground at all. Now like I said, doing a stoppy is not my goal, I'm just wondering if my front breaks are performing like they should. Jason | ||
| Bradj |
In the XB9S Service Manual, irregular or peaked front tire wear is listed as a possible cause of irregular handling. Could someone explain what "peaked" front tire wear would look like? Would that be the opposite of cupping? Anyone see anything unusual in these photos...other than the prominent chicken stripe in the middle?     | ||
| Wyckedflesh |
A peaked tire would have more wear along the strip between the lightest part of your tire (using your pics above for reference) and the chicken strips or possibly even out past the chicken strips. Its where the centerline of the tire is the highspot instead of smoothly around. Visually in pics its really difficult to diagnose a tire, alot of it is noticed more by feel. Running your hands along the tire from side to side and front to back will reveal lots of things that are really hard to see with your eye. |
