My fazer has lost stability on curves

[GkS]

Hi guys!

Well, the title says it all, but let's just look back a bit in order to have a complete view.

My fazer has always been a bullet, an arrow on open roads and pretty smooth when entering corners. After 30.000 excellent kilometers, I decided to change fork springs and put the ones from Ohlins, that Yamaha sells here in my country.
I've put the springs with a 10th grade spring oil and I felt the change imediately....nice and smooth, but a bit scary in the beginning, cause of difference I must admit. But it actually was a lot better once I started making trips.
I was enjoying it, when suddenly, not a long time after, one day on a ride, without understanding what happened I was dropped out of a corner, not going fast, tasting the asphalt and for my luck I didn't fall off a cliff....I'm not so inexperienced, I ride motorcycles something like for 18 years and have also been to tracks, but anyway I blamed my self for it, human error I said...I got distracted probably, completely fixed the bike (only a roller and a steering bar) and even if a problem on my shoulder is still there, I started riding again, without serious problems.

The main thing now is, that after a trip I had this summer, bike + me and gf + loaded, I kinda like feel now that on cornering bike is not stable any more. I feel like the tail is making strange movements and the front is getting lifted up, in such a degree that I actually fear leaning any more because of feeling that I'm loosing traction. I tried to increase shock's level, made the absorber a bit harder, but still that feeling of smoothnes is long gone.
Now I'm fearing that this is some kind of serious problem with the bike, but still I haven't figured it out yet. Mecchanic says it's the shock absorber that's wasted, how can that be? friends say it's psychological after the accident, it could be, but why didn't it happen imediately after the accident?.....I still don't know what it is for sure....

Anyone had the same feeling, any ideas what could that might be? Currently, odometer at 42.500km and tires are new and in perfect condition.
Just looking for ideas....

 

[Wolfman]

Are your fork tubes both at the same height in the top clamp? Maybe your steeering head bearing's need replacing???, this can make the front end feel real nasty...

There's a couple of possibilities, easy one's to start with.

:thumbup:

 

[GkS]

Are your fork tubes both at the same height in the top clamp? Maybe your steeering head bearing's need replacing???, this can make the front end feel real nasty...

There's a couple of possibilities, easy one's to start with.

:thumbup:

Thanks for answering so fast Wolfman!

Well, the mecchanic (yamaha) checked and found that front system is in perfect condition....so bearings, steering and tubes are all fine. His words..."It's perfect"

What other possibilities are there to check?
By your opinion, the original yamaha shock absorber can get damaged so soon? (2.5years, bike bought new)

 

[Wolfman]

Thanks for answering so fast Wolfman!

Well, the mecchanic (yamaha) checked and found that front system is in perfect condition....so bearings, steering and tubes are all fine. His words..."It's perfect"

What other possibilities are there to check?
By your opinion, the original yamaha shock absorber can get damaged so soon? (2.5years, bike bought new)

I have never heard of an FZ6 shock going "off", but it could also be a combination of not trusting your bike for a fair while after a nasty stack, this can make you feel mighty out of sorts on the bike, even if you dont think it is in a conscious manner....i mention this, cause i have experienced this...

Has your front tyre gone off??? Is it an older tyre, might of hardened up???

Tyre pressure??

Have your front suspension mod's come with gold valve emulators? do you have any adjustment inside the forks? the front suspension and the rear shock may not be "talking" to each other...maybe the rear is too hard now, front too soft???

Just a few more idea's...

:thumbup:

 

[GkS]

I have never heard of an FZ6 shock going "off", but it could also be a combination of not trusting your bike for a fair while after a nasty stack, this can make you feel mighty out of sorts on the bike, even if you dont think it is in a conscious manner....i mention this, cause i have experienced this...

Has your front tyre gone off??? Is it an older tyre, might of hardened up???

Tyre pressure??

Have your front suspension mod's come with gold valve emulators? do you have any adjustment inside the forks? the front suspension and the rear shock may not be "talking" to each other...maybe the rear is too hard now, front too soft???

Just a few more idea's...

:thumbup:

Tires and pressure not the case...

The Ohlins package had no gold valve emulators or any adjustment what so ever, they say it's made for this bike and you just plug and play....I have no clue if to touch or no, but it doesn't seem such a good idea.
The rear is probably harder now, but it feels a bit better, cause before it used to "swing" all the time...while front feels smoother than with the original...

Also, a friend of mine (FZMAN) did install the same spring upgrade, his bike is exaclty the same as mine in every detail and doesn't have this problem...though it seems like his front is a little lower in height....but can't tell exaclty.

 

[TownsendsFJR1300]

If the rear shock isn't dampening it'll cause havoc. Do you see any oil leakage from the shock seals?


Also, have you friend ride the bike and you ride his. See if he notices a difference and vice versa..

 

[GkS]

If the rear shock isn't dampening it'll cause havoc. Do you see any oil leakage from the shock seals?


Also, have you friend ride the bike and you ride his. See if he notices a difference and vice versa..

Well, to me it seems like the shock goes down and returns up again really slowly. Meaning, that when in turn, it absorbs and stays down, probably that's why I feel front being elevated, but can't be sure, any test I can do?. I also checked it's outer shell, no oil leakage...

I gave the bike to my friend, he said all well, except he feels steering in a bit higher position...that's strange cause everything seems in place...and steering bar has pointers for fitting, not that one can put it differently...

I didn't though ride his bike...maybe I should.

 

[TownsendsFJR1300]

Well, to me it seems like the shock goes down and returns up again really slowly. Meaning, that when in turn, it absorbs and stays down, probably that's why I feel front being elevated, but can't be sure, any test I can do?. I also checked it's outer shell, no oil leakage...

I gave the bike to my friend, he said all well, except he feels steering in a bit higher position...that's strange cause everything seems in place...and steering bar has pointers for fitting, not that one can put it differently...

I didn't though ride his bike...maybe I should.

If the shock is slow to return, its dampening.

Did the new springs up front tighten up the front end? If so, tightening up the rear spring adjuster may be necessary to even things back up. If the new spring is softer, try loosening up the rear shock setting, see if that helps..

Worse case scenerio, if you still have the old front springs, re-install them and see how it rides...

BTW, I had progessive springs put in the ft end of my old 2004 Goldwing along with Alll Balls steering head bearings. The front was way to hard for me, I ended up putting the stock springs back in. The shop had to raise he air pressure in the rear show to accomodate the front springs. The bike rode much harder after the spring swap and raised rear air pressure....

 

[iSteve]

I would check the tires again just because they look good doesn't mean they are. When the center of the tires get flat they can make transitions in and out of corners feel unstable.

Also after a spring change in the front end I went with 10wt oil and did not like the feel of the bike, like you I felt the rebound damping was a little heavy for street use. I changed to 5wt it seems to be more forgiving in corners and smoother on rough roads.

Also make sure the sag on the bike is correct. The rear shock is horrible and tightening the spring only changes the ride height. This can make the bike feel unbalanced.

 

[GkS]

I would check the tires again just because they look good doesn't mean they are. When the center of the tires get flat they can make transitions in and out of corners feel unstable.

Also after a spring change in the front end I went with 10wt oil and did not like the feel of the bike, like you I felt the rebound damping was a little heavy for street use. I changed to 5wt it seems to be more forgiving in corners and smoother on rough roads.

Also make sure the sag on the bike is correct. The rear shock is horrible and tightening the spring only changes the ride height. This can make the bike feel unbalanced.

Tires are brand new and I check pressure personaly every time I ride.

5wt oil is very thin, it feels like a pillow and with 10wt it's already feeling soft...

The sag....hmmm, front takes no other adjustment, the rear shock has very few ways to adjust......if it's not 5 and 4 is floating....6 is very hard, not many options there...

 

[pulverizer]

Try going down a click at a time on the rear and see how it feels. I had a similar feeling after I put some extra weight on the back of my bike (Topcase). I have the original suspension on the front and back, so I am not the same as you, but it is worth a shot.

When I had weight in the topcase, the front end felt very unstable. I had the rear set at 5 previously. I brought it down to 4 the other day and the bike went back to feeling a lot better in the front. This seems counter to what I thought would happen, since you would think more weight on the back would require more preload, but I guess it is a little more complicated than that.

So, I would suggest experimenting with some of those settings till you can find one that gives you the confidence back.

 

[spock]

after 47000 kms of use (and I guess abuse) my stock naked fz6 rear shock went off.

I started noticing it before because the usual preload was not enough - 5 - and I was feeling the bike dancing at the rear, so I had to put it on 7 to be a little more comfortable, and don't talk about carrying a passanger and luggage (I use givi v35 and top case), it was a real PITA, I felt like riding in sand every corner.

also when taking corners at the middle of the lean the rear shock suddenly was starting to compress and it felt like the bike was being dropped so I was easily scrapping pegs even at moderate corner entry speeds, not a good feeling at all.

so since I am a poor guy and at that moment I didn't have the money for high end stuff (and I don't have at this moment either) jijij I bought a brand new stock rear shock, after installing it and putting in the front 15w oil the bike suddenly felt really good and I was able to start gaining confidence while riding in sports mode with the usual 5 preload setting, even with a passenger I let it that way, unfortunately due to time and budget constrains no touring at all so I can't comment about handling with the side cases.

Cheers

 

[Motogiro]

The rate at which the rear shock is returning could be slower than what it originally was. This will cause 'packing'..... Rate of return is very important and this could be where you're feeling a difference. That rate may also change depending on position of the shock when you're compressing it with weight.

 

[iSteve]

5wt oil is very thin, it feels like a pillow and with 10wt it's already feeling soft...

The sag....hmmm, front takes no other adjustment, the rear shock has very few ways to adjust......if it's not 5 and 4 is floating....6 is very hard, not many options there...

The stock oil is 0wt

You can adjust the front ride height by using washers as spacers or cutting the long spacer (use a piece of pvc pipe).

 

[Marthy]

The rate at which the rear shock is returning could be slower than what it originally was. This will cause 'packing'..... Rate of return is very important and this could be where you're feeling a difference. That rate may also change depending on position of the shock when you're compressing it with weight.

I agree. Sound like a rear damper issue. Since you got the front end redone, I would think this end is good. I will rebuild the rear shock. Also, make sure that they know what you did on the front... I suspect a balance issue. You need to have the right spring rate split front/rear. Stiffer is not always better... especially, if I understand right, you did the spring and shock oil at the same time.

 

[GkS]

I agree. Sound like a rear damper issue. Since you got the front end redone, I would think this end is good. I will rebuild the rear shock. Also, make sure that they know what you did on the front... I suspect a balance issue. You need to have the right spring rate split front/rear. Stiffer is not always better... especially, if I understand right, you did the spring and shock oil at the same time.

Correct :thumbup:
Rebuilding or buing a new shock is what I'm also thinking....I would have liked a lot to try Ohlins to the rear also, but every month salary is less and less here, so it's really difficult now.

 

[FinalImpact]

What if the swing arm is binding and sticking. Might just cause some cornering issues. Pull the rear shock and lift the swing arm through its range of motion. It should be completely free and not bind at any point. Watch the chain tension that it doesn't bind and trick you.

Also, just because it is free with NO load, that doesn't mean it travels freely while loaded.

The question was asked; does the rear shock show any signs of oil seepage from the shaft area? If so, this could attribute to the new feeling. Is it seeping?
So, when you assembled the front fork springs you used the same spacers that came out? Some replace and tune the spacers by chopping PVC pipe. Perhaps the pipe broke on one side?

If the bike scares you to ride it; STOP! Pull the fork tubes and inspect them for equal compression rates. While they are off, remove and inspect your springs as the can break. Don't forget to pull the rear shock checking the rear swing arm bushings too.

Also the first couple of posts talked about riding 2 up. Where is your main complaint?

 

[RJ2112]

Correct :thumbup:
Rebuilding or buing a new shock is what I'm also thinking....I would have liked a lot to try Ohlins to the rear also, but every month salary is less and less here, so it's really difficult now.

George,

Most of the time when a bike crashes, and skids on the ground the fork tubes become twisted in their clamps. This will make the sliders on the forks much less smooth in their motion up and down the fork legs.

Even with the Yamaha mechanic telling you everything is perfect, please try the following:

1) loosen the upper triple clamp pinch bolts, the fender mounting bolts, and the front axle. Leave the lower triple clamp tight.

2) sit on the bike, and engage the front brake hard.

3) with the brake on, compress the fork as hard as you can. Shove it down violently. Do this 6 or 7 times. Make the fork compress as much as you can.

4) tighten all the bolts you loosened.

5) take the bike for a ride and see if it feels any better.

This is cheap, and simple; and it has a good chance of improving what's going on.

 

[GkS]

George,

Most of the time when a bike crashes, and skids on the ground the fork tubes become twisted in their clamps. This will make the sliders on the forks much less smooth in their motion up and down the fork legs.

Even with the Yamaha mechanic telling you everything is perfect, please try the following:

1) loosen the upper triple clamp pinch bolts, the fender mounting bolts, and the front axle. Leave the lower triple clamp tight.

2) sit on the bike, and engage the front brake hard.

3) with the brake on, compress the fork as hard as you can. Shove it down violently. Do this 6 or 7 times. Make the fork compress as much as you can.

4) tighten all the bolts you loosened.

5) take the bike for a ride and see if it feels any better.

This is cheap, and simple; and it has a good chance of improving what's going on.

Well RJ, this is the first time I ever hear about this process....it doesn't seem difficult to do so I might give it a try when I have the chance (free time and tools)...Thanks for your suggestion!

 

[TownsendsFJR1300]

I haven't had to do this on my FZ but have done it to other bikes in the past, it does help... Very good point