Need help: Oscillating steering at low speeds

[Biggie_B]

Greeting ladies and gents. I am having a steering issue that I hope you can help me with. A little while back I dropped my bike on the left side. Low speed, essentially stationary. Please see link below. I was able to fix the cosmetic damage, but have since noticed that the steering is a bit off at low speed. What do I mean, you say? As I slow down to about 10 mph, the handlebars oscillate from side to side until I come to a complete stop. The movement is not jerky or exaggerated, but it requires constant correction from me the rider. I know this is not a tire issue. The old tires exhibited the same behavior and I bought new tires (time to replace) since, but the problem persists. In my mind this is a safety issue and I would like to nip it in the bud. I have noticed that if I come to a harder stop, the behavior can be avoided, but if I come to a gentle stop, or need to cruise at a low speed either while speeding up or slowing down, there is play in the handlebars. This is terribly inconvenient as the bike tends to wander. Any assistance would be appreciated. Thanks!


Link to bike drop.....

http://www.600riders.com/forum/fz6-general-discussion/52610-seat-wiggles-normal.html

 

[Carlos840]

Greetings good sir,

Two things come to mind:

1: your bars were bent in the drop and this is making you do weird things because the bars are not symmetrical anymore.
Make sure the bars are straight, and also centered in the clamps, i have heard of bars being pushed of center, meaning one side becomes longer than the other, giving you uneven leverage.

2: your forks are not aligned properly, also a possible side effect from the drop.

To align them follow this procedure:

https://www.youtube.com/watch?v=vSunBRB6-r8

Just in case you don't have acces to youtube here is the short recap:

Loosen and then retighten the top clamp just to make sure the tubes are not pinched.
Loosen everything south of the top clamp, ie the lower clamp, axle pinch bolt, the axle, and the fender bolts.

While holding your front brake push down on your forks a few times so things self align.

Tighten the lower clamp, the axle, the pinch bolt and the fender.

All done.

 

[FinalImpact]

^^ all valid points and a good starting place.
I would also verify the trueness of the front wheel. It should be perfectly round and not wobble from side to side.
Throw an 8" tall block of wood under the header to get the front wheel off the ground and spin the front tire while holding a marker or pin next to:
- The wheels bead on both sides
- The tires edge and in the middle of the tread
- Both rotors

You might want want to pull the brake pads but if all is well, spinning it should free it also.
Anyway, the goal is to verify that once you make contact with marker it stays in contact and the distance remains equal regardless of where the wheel is clocked.

I understand the tire was replaced, so i think during balancing it would have been detected but maybe not. So you need to double check that nothing is bent and the bearings are ok.

 

[TownsendsFJR1300]

While the front wheel is in the air, push/pull on the lower forks checking for any free play in the steering stem/triples. There shouldn't be any.

You may want someone put some weight on the seat so you don't drop it.

Also, check the torque on ALL the bolts holding the front end on, especially the larger, upper center nut (in the middle of the upper triple clamp). Agreed loosening the front end and re-setting per the manual.

This issue may be related to your earlier drop, but that drop was so minor, this may just be another issue altogether.

BTW, how many miles on the bike?

 

[Biggie_B]

While the front wheel is in the air, push/pull on the lower forks checking for any free play in the steering stem/triples. There shouldn't be any.

You may want someone put some weight on the seat so you don't drop it.

Also, check the torque on ALL the bolts holding the front end on, especially the larger, upper center nut (in the middle of the upper triple clamp). Agreed loosening the front end and re-setting per the manual.

This issue may be related to your earlier drop, but that drop was so minor, this may just be another issue altogether.

BTW, how many miles on the bike?

.

Thanks for the replies everyone. I don't recall this behavior prior to the drop. The handlebars are likely the culprits. The left side bar took the brunt of the force on impact and upon visual inspection something looks off, for lack of a better word.

In response to your question, the bike has 4,800 miles.

 

[Carlos840]

.

Thanks for the replies everyone. I don't recall this behavior prior to the drop. The handlebars are likely the culprits. The left side bar took the brunt of the force on impact and upon visual inspection something looks off, for lack of a better word.

In response to your question, the bike has 4,800 miles.

If your bars are bent it might be the ideal time to change to FZ1 or Fz6R bars, here is a good thread showing the difference:

http://www.600riders.com/forum/fz6-mods/50793-fz6r-handlebars-drill-needed.html

 

[TownsendsFJR1300]

.

. The left side bar took the brunt of the force on impact and upon visual inspection something looks off, for lack of a better word.

This won't affect the occilation however your bike is faired, the
"Main Stay",( that supports the fairing) bends fairly easily. That may be what looks "off".

If you put the bike on the center stand, sit on the bike, forks straight ahead, and simply look forward. If bent, you'll see one side up more than the other, maybe pushed back a tad. Mine was bent about 3/4" from the PO. Another clue is the space between the fuel tank and the fairing at the very back. One side may be tighter than the other if bent.

Below's a pic of mine when I replaced it, double click to enlarge:

 

[MG-242]

I'll go with "check your steering head bearings" for $200 :thumbup:

 

[Biggie_B]

This won't affect the occilation however your bike is faired, the
"Main Stay",( that supports the fairing) bends fairly easily. That may be what looks "off".

If you put the bike on the center stand, sit on the bike, forks straight ahead, and simply look forward. If bent, you'll see one side up more than the other, maybe pushed back a tad. Mine was bent about 3/4" from the PO. Another clue is the space between the fuel tank and the fairing at the very back. One side may be tighter than the other if bent.

Below's a pic of mine when I replaced it, double click to enlarge:

Which part is the mainstay? Do you have another picture I can take a look at? Thanks

 

[TownsendsFJR1300]

Which part is the mainstay? Do you have another picture I can take a look at? Thanks

Part #14 is the main stay:

It bolts to the head of the frame (just forward of the steering head).
With your tip over, it, (if its bent), will be slight. You really can't take picture of it and see it unless its REALLY BAD.

As noted, the best was is to just sit on the bike, on the CC, and look forward. If its bent, you'll see one side up a little higher, maybe the mirror a little higher.

If its bent back (not likely in your case as the bike WASN'T moving), the space inbetween the fuel tank and furthest part, "tail" of the fairing, may be closer to the tank on one side or the other. I simply slip say my pointy finger and see how far it goes in on each side, should be about the same. A little off isn't a big deal.

The stay, even if it is bent, won't hurt anything, it just bothered the heck out me looking forward and the bike looked crooked...

Yamaha Motorcycle Parts 2005 FZ6 - FZ6ST COWLING 1 Diagram


Should it be bent, its MUCH EASIER to just replace it.

Double click to enlarge..

Partzilla parts pic & the other pic of my bike, (don't think it'll help at all) with the bent main stay. You can see where the mirrors (two bolts) attach to. It sticks out fairly far and does tend to bend if you fall over hard enough. You can see by the damage on the plastic, the bike was moving a little (he was doing his first wheelie!)