Front end issue

[moto_fz6n]

Hello guys,

A couple of years ago I've bought a 2008 FZ6 N with around 27.000 km / 16872 miles and now I've got around 33 k km. Pretty soon after I bought the bike I stared hearing strange sounds coming from the front end. I've asked a couple of guys from a local garage to take a look at it, they tested the bike on the road and seamed fine. In time I've got "used" with the strange sound and ignored it. It;s not something constant, it only manifests i hard braking. Something like a knocking sound is coming from the left side of the front end. ( I'm not really sure if the sound is made when the suspension is compressed or released. ) I tried to reproduce the sound at a stand still by pressing like a mad man on the handle bars ) but everything worked fine and no knocking sound.

And guess what, ? something finally gave up (......

Is this what I think it is ?

 

[TownsendsFJR1300]

Well those forks are off something else, NOT an FZ6..

Besides the seal leaking, bushings inside the fork could very well be worn and need replacement.

I would definitely be checking the steering head bearings that their not loose, worn out, etc.

ANY CLUNKING in the front end is not good..

 

[darius]

As Scott said, it looks you have alien components. More pics including wider shots would be helpful.

 

[moto_fz6n]

Well those forks are off something else, NOT an FZ6..

Besides the seal leaking, bushings inside the fork could very well be worn and need replacement.

I would definitely be checking the steering head bearings that their not loose, worn out, etc.

ANY CLUNKING in the front end is not good..

Are you sure about that ? They look the same to me - generic picture. I've also attached a few older pictures from my phone. I will try to clean up the oil, and come back with some fresh ones.

Regarding the steering bearings. A mechanic tested them by lifting the front end from the ground and slightly moving the handle bars left right...he said there was no play in the bearings.
Are there other things I need to check, to makes sure the bearings are ok ?

Also, are there any connecting components in the lower part of the front end (except the brake calipers ..etc ) or is just a big chunk of aluminium ?

Thank you.

 

[darius]

OK the forks look stock. The leak in the first pic is likely to be the seal and they're more likely to blow after drying out without the lubrication that the fork oil offers.

Can you trace back the oil back to the fork dust cap? I don't see how it could be anything else really. Perhaps you have had a small leak for a long time and the fork leg started to run dry and causing noise before blowing completely.

A fork seal set is ~$30 from Yamaha. This would be a good time swap fork springs if they're too light for your weight.

 

[zixaq]

You almost certainly have a fork seal that needs replacement, so service the forks first and get it back together. If the noise persists after that go hunting for more complex problems.

Fork service is relatively simple & cheap, and more than likely you're sporting seals and fork oil from 10 years ago (gross).

 

[moto_fz6n]

OK the forks look stock. The leak in the first pic is likely to be the seal and they're more likely to blow after drying out without the lubrication that the fork oil offers.

Can you trace back the oil back to the fork dust cap? I don't see how it could be anything else really. Perhaps you have had a small leak for a long time and the fork leg started to run dry and causing noise before blowing completely.

A fork seal set is ~$30 from Yamaha. This would be a good time swap fork springs if they're too light for your weight.

I wasn't able to find any trace of oil coming out from the dust caps :O, they look pretty good. I've cleaned the area and then pressed on the handle bars a couple of times and also pulled on the front brake leaver like hell but no oil came out.. I thought I will find some cracks in the aluminium in that area but everything looks ok. ( what do you think ? Btw the "oil drop" from the last picture is from the chain cleaner I've used to clean the forks...)

I've also looked for broken brake hoses but if nothing came out after this experiment I don't think there is an issue here ( btw the brake fluid is at the top level...).

You almost certainly have a fork seal that needs replacement, so service the forks first and get it back together. If the noise persists after that go hunting for more complex problems.
Fork service is relatively simple & cheap, and more than likely you're sporting seals and fork oil from 10 years ago (gross).

You could be right, I don't think the previous owner(s) did any service on the forks. After the service, I will return with feedback regarding that noise....


Thanks

 

[darius]

You must be able to trace the fluid. It's either fork oil or brake fluid if it indeed came from your bike's front end. If you have a blown fork seal, there would be a thin film of oil from pumping the forks. It would also be prone to leaking tipped on the side stand for the left leg.

If it's brake fluid, the fluid color would match that of your fluid in the master cylinder. Clear if new or yellowed with age. You can zip tie the brake lever to put the system under pressure as you check for leaks.

 

[TownsendsFJR1300]

Yep, their stock forks. It almost looks like that section has a crack in it. I never heard of that happening on the FZ and have to doubt it.

It does look like old fork oil. If it was brake fluid, he would have ran out a long time ago and lost his brakes.

I suspect, the PO knew (and acknowledged) the fork seal leak. I suspect it's all leaked out now, thus no more to show. You don't know how much it lost prior to you buying it, so that's a crap shoot.

Oil has a very different feel than brake fluid but both taste like chicken...

Yank them forks and do a close inspection for metal particles, anything amiss...

 

[moto_fz6n]

Thanks guys for all the suggestions, I will remove the forks for service and come back with feedback.

 

[Ohendo]

Something like a knocking sound is coming from the left side of the front end.

Aside from your fork seal issue, you have this knocking sound you mentioned. One cause could be slight engine movement on hard braking if the mounting bolts aren't torqued properly.
I had this issue myself, would hear a loud knock when braking, and couldn't figure it out. Changed out the steering head bearings (needed it anyway) but the knock persisted.

Eventually I re-torqued all of the mounting bolts, and voila, knock sound disappeared. Hopefully it's as simple as this for ya.

 

[moto_fz6n]

Aside from your fork seal issue, you have this knocking sound you mentioned. One cause could be slight engine movement on hard braking if the mounting bolts aren't torqued properly.
I had this issue myself, would hear a loud knock when braking, and couldn't figure it out. Changed out the steering head bearings (needed it anyway) but the knock persisted.

Eventually I re-torqued all of the mounting bolts, and voila, knock sound disappeared. Hopefully it's as simple as this for ya.

Wow, what the hell :O, I will check my engine bolts then.

I'm a pretty heavy guy ( i think ) ) around 189 -198 pounds and sometimes I take my girl for a ride as passenger (she is ~ 134 pounds). Since I will service the forks , should I get harder springs also ?


Thank you