Knocking in front forks since Andreani upgrade

[jonno12345]

Finally got around to fitting my Andreani fork cartridges over the weekend. All went fine (except being unable to remove one retaining bolt from the bottom of the fork but a local garage with an air gun sorted that!). I have yet to ride it, but just tested them by sitting on the bike, full front brake on and pushing down on the front. I'm now getting a lot more swishing/wooshing than I ever did with the stock cartridges, but I don't mind that so much. What I'm a bit more concerned about is that, at the bottom of their travel, I seem to be getting a bit of a knock sound, almost like something hitting plastic? I'm fairly confident its within one of the forks, although I can't isolate which one.

 

I'm using a 2.5w oil in the compression leg and 5w in the rebound, incase that could be related. I also made a 125mm airgap from the top, but I think I may have made a mistake and did it from the top of the silver 'inner' tube, instead of the top of the golden tube, which maybe added another 10+mm or so. Could it be a lack of (or too thin) oil? Or have I put something together wrong? Or is this normal, although I'm not sure it should be?

 

Thanks!

[piotrek]

I ran 2.5W and 3W in the active leg, but valving is probably different than yours. No issues here with knocking in the forks or other unusual sounds, but what you describe could be the floating brake rotor just at beginning of the rebound stroke. Have a third ear available?... have them have a closer listen.

125mm is pretty high for oil level, and at that value I think you would be filling the outer tube as well, unintentionally. Riding is believing though... have a go and see how it feels.

If you have any doubts about the assembly... take them apart.

[jonno12345]

Thanks, it's seems to sound different to what I remember now, like a creak at the bottom of the travel. I'm also wondering if I have the wrong spring rate, the supplied springs had 7.8 printed on them I believe and they seem quite soft (I'm around 78kg). I cant work out if I'm running them on max or minimum preload either, I'm guessing clockwise on the gold hex nuts it's to increase? If so, I think they are maxed..!

[piotrek]

Racetech online tool outputs 0.9kg/mm for your 78kg weight, which is 8.8N/mm, although I found RT spec a bit on the aggressive side. I am 90kg and run a 0.9kg/mm spring, and it works very well. Can you set sag with a little room to spare? CW to increase preload.

That creaking could be the spring compressing and bowing off center... which causes it to rub against the inner tube. That is not abnormal, but than again... not able to hear what you're hearing, so YMMV.

FZ09 board has a lot of information on the Andreanis. Have a read on there.

[dazzler24]

@jonno12345Check out this link.  It may answer your issue with the knocking and their fix.  There is also a video in there, within the thread, that demos the sound for comparison with what you're getting.

FYI... I have the Andreanis as well and also have a 'knock' but it doesn't seem to affect performance.... although still annoying.🙄

Andreani Cartridge install.....Unbelievably easy!!! | Page 11 | Yamaha FZ-09 Forum

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Edited September 19, 2019 by dazzler24

[piotrek]

6 hours ago, dazzler24 said:

@jonno12345Check out this link...

Andreani Cartridge install.....Unbelievably easy!!! | Page 11 | Yamaha FZ-09 Forum

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This is the thread that brought me to the brink of ordering a set a a few years back. Questions remained, so I never pursued. Very good write-up though, and seems the OP in the thread was a happy camper in the end. I recall that he bought springs from another manufacturer and modified the spacers to suit.