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front end wobble

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Pacodog

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I know I saw this somewhere but after a short search I gave up looking. Out riding my 07 bandit and when I take my hands off the bars at low speed, 10 mph the front end wobbles back and forth. It doesn't do it at higher speeds.
My front tire has about 2k miles and is a bit scalloped but not too bad. I have 34 psi in the tire. Only other comments are I have reworked the forks with springs and such and have a fork brace.

Any ideas?
 
Check to make sure your forks are even. Uneven forks may not produce a wobble, but they could make a slight wobble worse.

Sent from my SCH-I545 using Tapatalk 4
 
Don't take your hands off the bars! (Doc it hurts when I do this. "Well then don't do that.)
Sorry I couldn't resist.:trust:
 
So many things can cause the wobble. I got a small one on my bandit last year with the larger and more loaded Givi top box on it. Got it to go away when I added some more preload to the rear. Once I developed a similar deal after changing tires on my '02 BMW R1150GS in Maine. Never could get it gone. Changed front tire about 8,000 miles later, and, it was gone. That company had a bad run of tires that caused that on some bikes. I ran those same tire a few years later without a problem , same load, same bike. Make sure your sag is set around 1/3 of suspension travel, I don't get too techco with this, but like it in the ball park. Maybe add a bit of preload to the rear to see if it changes. As mention, make sure the steering head bearing are not too loose.
 
Thank you for the reply's.
YoDoc - The front fork comment makes sense since I have done work on the front end. Do I run a string line from the back tire to the front?
Toe Jam - I thought about that when I posted but did it anyway.
Yama- I will check the bearings, thanks
Andy - front and back sag set at 1/3 travel. Front tire, remains to be seen?
 
I would reduce the air pressure to 32, over inflation causes problems, may want to start at 30 and increase a pound at a time. I had a FJ600 that did not like Dunlops, head shake city. Scalloped them, no other brand did this. You can try moving the forks up or down in the triple tree, not much a few cm to change weight bias.
If you can get a different brand tire as this may be the easiest fix. BTW you did not mention the brand and size.
 
I no longer have a Bandit but when I did I ran 38psi up front and 42psi in the rear. Never had a wobble problem with PR2 or PR3. Do most of you run lower tire pressure? (ie 34 or 32 psi)
 
I had a similar situation with my V-Strom. It would be OK with a new rear tire, but soon the problem would return. I didn't feel in danger, but it was irritating. I replace the steering head bearings with a set of roller bearings from AllBalls. The original factory bearings were ball bearings in a plastic or nylon cup. A really crappy idea. Why spend the money to put magnesium panels in some places and save $2.00 on steering bearings?

Problem solved.

Pat McDonald
 
This happened a long time ago to a buddies Honda. He had it serviced new tire and they put both front wheel washers on the same side and it made it shimmy a little.
 
Also check your rear tire pressure. Even though it's an apples to oranges comparison, my Harley will do the same thing if the rear tire is low or if there isn't enough air in the forks and rear shock. On dirt bikes, air in the forks is usually a bad thing (until Honda started using air forks on their MX bikes) so I always drained it out of my forks on the Harley. After mentioning the head shake to one of the Harley mechanics, he told me to check my manual and it does state there is a minimum air pressure required in the forks for the '01 Ultra Classic.
 
There are 2 steering head bearing nuts. Should I tighten both of them or just the one on the top? The reason I ask is I will need to tear the front end apart to get to the one under the top triple tree.
I also noticed a strange wear pattern on the front tire. If you look straight down on the front tire the right side has a radius and the left side has a flat spot.
 
Pacodog said:
There are 2 steering head bearing nuts. Should I tighten both of them or just the one on the top? The reason I ask is I will need to tear the front end apart to get to the one under the top triple tree.
I also noticed a strange wear pattern on the front tire. If you look straight down on the front tire the right side has a radius and the left side has a flat spot.
Click to expand...

The bottom steering stem nut is the only one that adjusts the play on the stem bearings, and you don't need to remove the top triple tree or take the forks apart to adjust the lower stem nut, just place the bike on the center stand and loosen the top stem nut and the top triple tree pinch bolts and then use either use a punch and a hammer or a thin hook type spanner wrench to the turn the lower stem nut, then tighten the top stem nut and pinch bolts. This procedure is also specified in the factory service manual under under the steering section.
 
Thanks Scott, in regards to your previous post on fork alignment, if you have a fork brace at what point in the sequence would you tighten up the fork brace bolts?
 
When putting the forks back on my bikes, I just have them in the triple clamps very loose , supporting the bike with a jack, and tighten the Axle Nut first. Then the bottom pinch bolts. Then the bolts on the triple trees. So far, I've had good luck with that.
 
Pacodog said:
....
I also noticed a strange wear pattern on the front tire. If you look straight down on the front tire the right side has a radius and the left side has a flat spot.
Click to expand...

Called cupping, under inflation, mis-aligned front to rear, loose steering head, wheel bearings
To check the steering head bearings. Get the weight off the front, tire in the air, Handlebars should move smoothly, not sloppy loose but with some resistance, If you push front to rear , like try to pull up the front tire , there should be no movement or sounds coming from the front.

What brand of tire and how many miles are on it?
 
Pacodog said:
Thanks Scott, in regards to your previous post on fork alignment, if you have a fork brace at what point in the sequence would you tighten up the fork brace bolts?
Click to expand...

Once everything is fully aligned, bolted down and bike on center stand put the fork brace back on! :)
 
somewhere on the web there is suzukis official answer to this problem, i have read it, but alas i can no longer find it, someone else maybe able to find it,if i remember it has something to do with fork angle and tire circumference altering with camber of the road and a host of other things. this is a good watch from many years ago about the same problem

http://www.youtube.com/watch?v=z3OQTU-kE2s&feature=youtu.be
 
I did the front end alignment per instructions in this post. I also tightened up the headset bearing. I tightened up the lower motor mounts which seemed to be undertorqued. I took it for a ride. The low speed wobble went away but it does wobble at higher speeds, ie 50 mph. I think the scallop on the font tire may causing the problem.

One thing I noticed was the vibration which I usually feel at 3500 rpm was pretty much gone. I have had that vibration since I bought this bike. I guess the motor mount bolts are the reason for this. I plan to re-torque all the motor mounts next.
 
Man, I run 30# on the front and 28# on the rear of my track bike (SV650). On my road bike (ST1300) I run one pound over O.E.M. recommendations. Hard front braking on a under inflated tire will cause cupping. You can't fix a front end problem with a bad tire on the bike. Good luck.
 
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