VFR 800Fi knocking noise

[cazkettles]

Hi, I got a 1999 VFR 800FI last week, and it has a strange knocking noise coming from the front.

When the bike is idling there is no abnormal noise - sounds fine at any rev range.

If I put it into any gear and let the clutch out it starts making a knocking noise. As far as I can tell it's not coming from the gearbox/clutch itself.

I took the fairings off today to see if I could get a better idea but still not got a clue.
I took it to a mechanic before I took the fairings off but he wasn't sure, I would have to book it in to let him have a proper look at it (Which is a last resort as I'm broke after buying the bike).

Any ideas?
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Bikes: 1990 Yamaha TZR125 (Sold), 2005 Honda CG 125 (Sold),1999 Honda VFR 800FI (Stolen and Burned), 1988 Honda CBR400 Babyblade (Sold), 2001 Yamaha Fazer 600 FZS (Sold), 2007 Triumph Daytona 675

[Noxious89123]

Drive chain? Check it for wear and slack.

When you say put it into gear and let the clutch out do you mean riding it normally, or with the rear wheel off the ground? I know you said it sounds like it's coming from the front, but I had the same with my 125. Chain was knackered, new chain and the knocking/clunkynss went away.
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'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[cazkettles]

Either / both really, makes the noise either way - with or without the back wheel turning.

It seems to go away at higher revs too.

I'll hopefully have someone to help me tomorrow (So they can let the clutch out while I attempt to find where the noise is coming from).
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Bikes: 1990 Yamaha TZR125 (Sold), 2005 Honda CG 125 (Sold),1999 Honda VFR 800FI (Stolen and Burned), 1988 Honda CBR400 Babyblade (Sold), 2001 Yamaha Fazer 600 FZS (Sold), 2007 Triumph Daytona 675

[cazkettles]

Found where the noise is coming from
I took the tank half off, and made the bike make the noise again, there is a flap on the top of the air box that goes up when the clutch reaches biting point. The spring attaching it must be loose, so it's hitting the top of the airbox and making a noise.
Off to fix it now
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Bikes: 1990 Yamaha TZR125 (Sold), 2005 Honda CG 125 (Sold),1999 Honda VFR 800FI (Stolen and Burned), 1988 Honda CBR400 Babyblade (Sold), 2001 Yamaha Fazer 600 FZS (Sold), 2007 Triumph Daytona 675

[Noxious89123]

A flap on the airbox you say? Weird! Pics?
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'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[cazkettles]

It's the air intake control thing for the airbox. It goes up at low revs and down at high revs (allowing more air in). I've got some photos on my phone, I'll try and get them up at some point this week..

I put stuck some foam on the bit it was banging against, so noise is gone Bike is all back together again now too.
____________________
Bikes: 1990 Yamaha TZR125 (Sold), 2005 Honda CG 125 (Sold),1999 Honda VFR 800FI (Stolen and Burned), 1988 Honda CBR400 Babyblade (Sold), 2001 Yamaha Fazer 600 FZS (Sold), 2007 Triumph Daytona 675

[cazkettles]

Here's a photo of it: https://www.vfrdiscussion.com/forum/uploads/monthly_05_2011/post-19514-0-96988200-1304210984_thumb.jpg


From a bit of a look read around on google it appears that a lot of people remove it completely to get better performance.. Wish I'd read that a few hours ago
Though it's fairly easy to get at now I know how to.


https://johnny.chadda.se/article/pair-and-flapper-mod-with-bonus-snorkel-mod-for-vfr/
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Bikes: 1990 Yamaha TZR125 (Sold), 2005 Honda CG 125 (Sold),1999 Honda VFR 800FI (Stolen and Burned), 1988 Honda CBR400 Babyblade (Sold), 2001 Yamaha Fazer 600 FZS (Sold), 2007 Triumph Daytona 675

[RodRides]

It is common on the 02 and later VFR's for the cam chain tensioner to slack and the chains to get noisy. You can re-tension them though. See Video
https://youtu.be/UuYjv1t-pn8
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RodRides
https://youtube.com/channel/UCO_50CcJ2oAP9mH2g_8AKlg

[bacon]

No cam chain on this bike so your video is irrelevant to this thread. Besides he solved it already.

[pikey666]

[MCN]

Baw Sack.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[stinkwheel]

[xX-Alex-Xx]

[stinkwheel]

[Jozzer]

[xX-Alex-Xx]