Front suspension shot?

[CHEMIKER]

I noticed my bike handling very strangely today, all of a sudden. In turns it felt like the front tire was flat - very sluggish controls. I checked the pressure in both tires - fine. Rode it again and noticed that it just feels strange to take low speed turns. Hard to describe. More importantly, it seems like the front suspension just compresses fully when I'm braking, and doesn't rebound like it should. When riding, if I grab some front brake, the front compresses, but less than it used to, and doesn't spring back when I release the brake. It does rebound when I accelerate though.

Anyway, in case my description isn't conclusive enough, I have 2" of sag on the front from just sitting on it. Is that normal? I'm 160# with gear on. Also, I can tell from the tubes that my suspension has been compressing up to 4" and I'm just riding normally on my commute. Is that normal?

Any help is greatly appreciated, I have never done suspension, and this is pretty mysterious to me. Could I have a broken spring?

 

[Kazza]

Don't know if it's related, but Mike had a problem with his XJR1300 once (fixed under warranty). Luckily this happened when he got home, at the bottom of the steep driveway down to the shed.

The forks stuck down. Couldn't move them at all. Trailered the bike to the Yamaha dealer and they had to rebuild the forks internally. Completely shot. They said they hadn't seen it before.

If it had happened on the highway on the way home 100 km/ph zone .....

 

[CHEMIKER]

Thanks Kazza, but thankfully they're not stuck - that sounds scary. I get full extension of the forks when the bike is on the centerstand.

I'm sure I'm not describing this right since I have no experience, but it seems that the front spends a lot more time lower in the first place, and is compressed more readily than it has in the past. I don't think it's bottoming out, but getting closer to bottoming out than it used to when on the brakes (even normally). It feels like the whole front end is collapsing under normal braking, and the controls are really "heavy" in turns.

 

[chomorro]

Hmmm i wonder if mine does this. I can visibly see that one of my forks is leaking a little. I will pay attention tomorrow on the ride to work.

 

[RJ2112]

I noticed my bike handling very strangely today, all of a sudden. In turns it felt like the front tire was flat - very sluggish controls. I checked the pressure in both tires - fine. Rode it again and noticed that it just feels strange to take low speed turns. Hard to describe. More importantly, it seems like the front suspension just compresses fully when I'm braking, and doesn't rebound like it should. When riding, if I grab some front brake, the front compresses, but less than it used to, and doesn't spring back when I release the brake. It does rebound when I accelerate though.

Anyway, in case my description isn't conclusive enough, I have 2" of sag on the front from just sitting on it. Is that normal? I'm 160# with gear on. Also, I can tell from the tubes that my suspension has been compressing up to 4" and I'm just riding normally on my commute. Is that normal?

Any help is greatly appreciated, I have never done suspension, and this is pretty mysterious to me. Could I have a broken spring?

I'd guess that your fork oil has gone South, and you are noticing the cr*ppy OEM springs more, as a result. When you get contaminants in the oil, it changes the viscosity, which will change how the fork responds. If the oil is thinner, the fork will compress and extend more easily than designed. It will feel 'loose'.

If the fork is staying more compressed than ideal, your steering will be 'faster' due to the steeper fork angle.

At 160 in gear, I'd think you would need .85Kg springs in the fork. Get single rate springs and replace the fork oil with fresh stuff. You'll be amazed at the difference.

 

[VEGASRIDER]

At 160 in gear, I'd think you would need .85Kg springs in the fork. Get single rate springs and replace the fork oil with fresh stuff. You'll be amazed at the difference.

Once again, spot on advice from the expert. I weigh close to you Travis, probably a bit more and I had Race Tech Springs installed with heavier fork oil. The oil can vary from 5 to 15 weight. I think the stock comes with 5. You can go on their website, enter your weight and it will automatically figure out your springs. It will most likely come out to .85.

 

[Ben_H]

If you are interested i have a pair of forks for sale from my 07 7,500 miles only $150.00 + shipping they look like new no leaks

 

[CHEMIKER]

I'd guess that your fork oil has gone South, and you are noticing the cr*ppy OEM springs more, as a result. When you get contaminants in the oil, it changes the viscosity, which will change how the fork responds. If the oil is thinner, the fork will compress and extend more easily than designed. It will feel 'loose'.

If the fork is staying more compressed than ideal, your steering will be 'faster' due to the steeper fork angle.

At 160 in gear, I'd think you would need .85Kg springs in the fork. Get single rate springs and replace the fork oil with fresh stuff. You'll be amazed at the difference.

Thank you! I wouldn't say that it's faster as much as feels unstable or maybe sluggish if anything. Like I have a flat tire and my bike is harder to push down in a turn, and then wandering on me.

 

[dxh24]

Definitely sounds like something internal is going... good news is it's an excuse to upgrade the innards a bit :thumbup:

It's not visibly leaking correct? If it were, new fluid and a new seal should fix it... sounds like something isn't right internally though...

 

[CHEMIKER]

Definitely sounds like something internal is going... good news is it's an excuse to upgrade the innards a bit :thumbup:

It's not visibly leaking correct? If it were, new fluid and a new seal should fix it... sounds like something isn't right internally though...

No leakage at all. Both forks are dry as a bone.

 

[Motogiro]

It sounds like one spring failed. Especially if this is a new trick the front end is doing. I don't think the oil changed property over night and you just came off a long trip on the bike and prolly would have noticed it behaving differently.
I'm thinking the oil is used more as a damper and would reduce compression/decompression rate depending on viscosity, valving and age. The springs should return the suspension to the same height regardless of oil condition. At at any rate. If you have to service it you might as well put the good stuff in. Springs and oil.

 

[CHEMIKER]

Thanks Cliff! Yes, that's what I can't get around, this is acting very strange, very suddenly. The suspension has always felt soft to me, but not unstable. This was like one day was acceptable and the next day it's not. I'll be ordering springs and oil today.

 

[FZ6-ZN]

It's a sign that its time for an R6 fork upgrade


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I am here: http://maps.google.com/maps?ll=-29.745701,30.818386
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[mxgolf]

I have had Ohlin springs for months and Ohlin Fork oil and have not done the change yet. I need to do it soon. That probably will help your situation. :thumbup:

 

[CHEMIKER]

It's a sign that its time for an R6 fork upgrade


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I am here: Google Maps
- FZ6-ZN - Sent from my iPad using Tapatalk...

What is the advantage of doing the R6 versus just springs and oil besides adjustability and upgraded brakes? I already have the '07 with the new brakes, and not sure I really need the adjustability. I'm just starting to do research on this, so I'm open to any suggestions/info I can get.

 

[Erci]

It sounds like one spring failed. Especially if this is a new trick the front end is doing. I don't think the oil changed property over night and you just came off a long trip on the bike and prolly would have noticed it behaving differently.
I'm thinking the oil is used more as a damper and would reduce compression/decompression rate depending on viscosity, valving and age. The springs should return the suspension to the same height regardless of oil condition. At at any rate. If you have to service it you might as well put the good stuff in. Springs and oil.

Spot on! I have little experience with moto suspension, but have a LOT of experience with mountain bike suspension.. which really is the same thing, but scaled down

When oil breaks down, fork tends to become more bouncy. Think of it as putting thinner oil in.. it flows through the valves easier thereby speeding up compression and rebound.

My guess would be
1. Failed spring, as Cliff said (never seen this before, but certainly possible).
2. Sticky oil seal(s).. if they're dried up they can make the fork stay stuck down part of the way.
3. This is unlikely, since you didn't crash, but if legs are out of alignment the fork will become sticky too. Easy to loosen up all the clamps on triple trees and just give it a bit of shake and tighten everything back up.

So, I'd attack it by aligning the legs first. If that does nothing, I would open up the legs and check springs. If both springs are fine, I would replace oil and seals. OR.. buy the fork listed above for 150

 

[Hellgate]

Thank you! I wouldn't say that it's faster as much as feels unstable or maybe sluggish if anything. Like I have a flat tire and my bike is harder to push down in a turn, and then wandering on me.

How's the front tire? A worn one can make is difficult to turn.

 

[CHEMIKER]

How's the front tire? A worn one can make is difficult to turn.

It looks pretty good to me. Good tread, good pressure, a little flat in the center, but not much. I just did a >1000 mile trip with lots of twisties and didn't notice any problems.

 

[novaks47]

How many miles on the moto?

 

[MoeDog]

cant help you much on figuring out the problem but if you decide to work on it yourself let me know maybe i can be the camera man to record a how to video :thumbup: and maybe i can service my forks too