Gen II Front End Wobble

JMundy

JMundy

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So I did some reading and not a lot on this topic, so I hope this isn't a repeat. When riding my bike to work today (2008 FZ1 8800 miles) I let go of the bars to adjust a glove and the front end started to wobble back and forth. Started off very light and gradually got worse. This was all in about 5 sec. The bike never felt unstable, and I barely noticed it. If I barely held onto bars it would be just fine (like index finger and thumb with only one hand) but with no holding at all it would happen.

I did just place on my side Givi cases on the bike and in my left one I have my jacket liners, pant cover, small amt of tools and my clear shield for my helmet. Right side has nothing in it. My Givi tail case had my small backpack with iPad and an extra pair of gloves. It conintued to do this in all speeds from 20 - 45 mph, with and without throttle lock engaged and with/without applying rear brake. Also tested on different roads to see if it was the road. I have never noticed this before and I ALWAYS have my tail case on my bike, with the backpack and extra gloves when commuting to work. Just added sides for a short ride im doing tonight with the wife.

I met a co-worker for coffee and to see if it was the cases I placed my side cases in his car and the wobble was gone. I tried multiple speeds and times and I never noticed it. Also checked front tire, feels good, and all weights are still in place on rim.

So Question: what do you think the culprit is? Could it be from the extra weight from cases? Could it be from cases not having the weight evenly distriputed? I did a ride 300 miles ago with all luggage on, slightly loaded (more in it than I had in there now)and im pretty sure I did some riding no handed and this never happened.

Any suggestions?
 
Just a guess...
maybe the side bags add some air resistance, causing some type of resonance at the lower speeds you are at. Maybe turbulent air around the tail causing the bike to move side to side slightly and therefor the bars wobble?
Were you wearing something different then the last ride? Maybe you were carrying more weight last time so it was more stable?
 
Try putting all those items into the right side case and leave the left empty. Here's my reason: With the stock heavy OEM potato-canon exhaust, Yamaha managed to somehow balance the bike. In stock form, let go and the bike tracks true/straight! But since you've removed that weight and added the slip-on, the bike is now unbalanced, heavy to the left, light to the right. Let go and the bike wants to not go straight any longer. So, by adding weight to the left, you're increasing the difference. Try the weight over the exhaust instead.

I have Norm to thank for pointing this out first and it's very much true as I've witnessed it first-hand on his bike, mine and then my wife's FZ1. Norm didn't like it to the point that on his current FZ1, he refused to remove the stock exhaust so he can keep that balance.

The other suggestion would be to get a steering stabilizer.

Are you running the stock 190/50 in the rear and OEM suspension? Some have a 55 which changes the rake thus affects the handling. Are the forks at the OEM height (top flush with the triple) or are they raised at all in the triple? This has the same effect as the 55 rear. Both make the bike corner faster but track a straight line a little less stable.

Do those cases fit very tight? No wobble to them? even a little play will create that resonance that vandal_xx mentioned above.
 
vandal_xx said:
Just a guess...

Were you wearing something different then the last ride? Maybe you were carrying more weight last time so it was more stable?
Click to expand...

Same gear on myself as last time. The last time I had a friends gear in the right case, his lunch and riding liners

Cobalt said:
Try putting all those items into the right side case and leave the left empty.
Click to expand...

That's a great idea and makes sense. Only reason I would think maybe it shouldn't matter is because it tracks just fine without the side cases on, so would the lighter exhaust matter, but with the lighter exhaust AND more weight on left side it could affect it.


Cobalt said:
Are you running the stock 190/50 in the rear and OEM suspension? Some have a 55 which changes the rake thus affects the handling. Are the forks at the OEM height (top flush with the triple) or are they raised at all in the triple? This has the same effect as the 55 rear. Both make the bike corner faster but track a straight line a little less stable. .
Click to expand...

Suspension appears to be stock setup, and previous owner made no mention of any aftermarket suspension. I am second owner.


Cobalt said:
Do those cases fit very tight? No wobble to them? even a little play will create that resonance that vandal_xx mentioned above.
Click to expand...

They fit very well. if you want to call it some wiggle, it would be measured less than a mm of play.

I have balanced out the weight between both side cases and ill see if that helps, and if not then ill try it all on the right side. <--- That was a pretty smart idea and makes sense why it could be that. My main concern is for it to not be something bad as with a 150+ mile ride with wife tonight I want to be safe.
 
JMundy said:
My main concern is for it to not be something bad as with a 150+ mile ride with wife tonight I want to be safe.
Click to expand...


Just don't let go tonight. ;)

Can you shim the mounts at all to make them perfectly tight?

Keep us posted and let us know the results. Always helps others when a thread comes full circle with the correct answer. :D

Ride safe!!
 
So just went and ran an errand, and its still there. So on my way to where I was going, I had my side bags weight balanced, and still had wobble. On way back to work I had all the items in the right bag and still had wobble.

This is really wierd
 
I am guessing your front tire is cupped. A ever so slight cup on the tire will cause a wobble like your talking about on most bikes. How many miles on the front tire?
 
Like others said, front tire issue. I had a brand new Continental ConiMotion and it was doing exactly as you described and I only had about 500 miles on the tire when it started doing it.
 
Yeah, maybe you are over thinking it. Could be the tire is just starting to cup a little and it is not quite noticeable. I have had half worn tires seem fine and then cause wobble off and on. Maybe even a suspension problem starting to poke it's head out?
 
Spiker_47 said:
New guy here. I have the same issue. I discovered that the front tire air pressue was low. Increased it to 36 psi and the wobble went away.
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This was exactly it (or so I think so far). Got home and checked psi and it was just under 30psi with the tire warm from riding home. I thought I checked them when i got it home from purchasing but im thinking I was wrong. Ill definately be watching it and see if the psi goes down throughout next week. I was able to let go and had no play at all with all cases on and wife with me.

I have yet to ride it with just me and cases but I suspect it will be good. Ill know more soon and report back with final finding.

I am not sure on how many miles on the front tire, as i bought it start of summer and have put less than 1000 miles on it since purchase, but the tire looks very good. The rear is looking to need replaced after this summer, so ill just do both and have them all new to start next spring.

Thanks again everyone for the help/suggestions.
 
That's good news! Get some aluminum valve caps with the O-Rings in them. Those stems are the weakest point and always leak first. I've had a lot better luck with stable pressures with these in place.
 
What kind of tire is it. Continental tires had an issue with tire pressure loss. The one on my FZ6 would lose around 5-10 psi over a month and I could never find a leak in it.
 
How often do you guys change your valve stems? They guys I use to mount and balance tires says he only changes them when they look damages. I think every couple years or so. What do you guys think?
 
Well rode to work this morning and its still there :banghead:

I don't have a tire pressure gauge with me but I would hope tire pressure isn't low. So maybe it is starting to cup?

Well ill check pressure tonight and report back. Tires or not I was already planning on new rubber after this season.
 
How often do you guys change your valve stems?
Click to expand...

My 07 has the OEM valve stems. I mount my own tires and havent changed them. They are 46K old.
I will be changing them with this next set of tires. I 'll be installing the 90* AL valve stems.
 
I am going to get some 90s for my stems too. I have changed mmy own tires too. The problem is with balancing. It needs to be done with a machine IMO. I tried doing it with stands, but it is ever spot on like a machine.

Also, back to the wobble. BUMMER!! new rubber for sure!!
 
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