Tapping noise on '99 Thundercat 600

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Was riding a Thundercat today, for around 20 miles it was fantastic, after that there was a little tapping noise under acceleration. From around 3k upwards, gets faster with the revs and is audible on idle.

Bit worrying really.

Is it possible it could be one of the exhaust headers come slightly loose?

Valves were checked and adjusted 2000 miles ago. Bike has been standing for a month and a bit.

Casper · World Chat Champion Joined: 12 Jul 2010 Karma :

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Tightening them looks to be challenge of the century, have to really hope they are free enough.

I'm only guessing as its only after it got popped and banged. Laughing

lihp · World Chat Champion Joined: 22 Sep 2010 Karma :

Got a vid? May just be the "yamaha tick" google it Smile

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Yamaha tick seems to be when engine is warm.

I'll check later as its stone cold now

weasley · World Chat Champion Joined: 16 Oct 2010 Karma :

Almost certainly a header gasket. Better start the Plusgas on the stud nuts now.
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~~Yamaha XJ600 | Yamaha YZF600R Thundercat | KTM 990 SMT~~ | BMW F900XR TE

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Taken a video of it in the highest quality that I could.

linky - https://www.youtube.com/watch?v=kmZUPVLewtI&feature=youtu.be - mainly hear it at 27 seconds onwards

When you are riding under load, its very noticeable. Power doesn't seem to be down but I've not ridden a 600 IL4 sports thing in ages.

It increases with revs in any gear and starts being noticeable at 3k onwards

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Anyone?

J.M. · World Chat Champion Joined: 27 Mar 2011 Karma :

A quick Google search reckons that it's harmless.

Clutch rattle was mentioned. Also said it could be the clutch basket if the sound goes away with the clutch pulled in (Neutral doesn't affect it, try pulling in the clutch).

Tried taking it to a Yamaha dealer? Should be able to get some free advice?
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2004 R1 & 2018 XSR900

Casper · World Chat Champion Joined: 12 Jul 2010 Karma :

I had a friend with the Thunderace and that rattled from the clutch. Being behind the fairing made it sound louder. Does it go away when you pull the clutch?

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Think the clutch might be on the other side...it sounds like its from the top end, which is stopping me riding it as its new to me and for once, just once I'd like a nice looking and great riding bike Laughing

Watched in HD and seems like there is something at 27 seconds that flies out of the engine Laughing

weasley · World Chat Champion Joined: 16 Oct 2010 Karma :

Having watched the video I'm still thinking header gasket.

Can sounds nice too.
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~~Yamaha XJ600 | Yamaha YZF600R Thundercat | KTM 990 SMT~~ | BMW F900XR TE

P. · Red Rocket Joined: 14 Feb 2008 Karma :

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Think I found the noise.

After spending half an hour getting one panel off Rolling Eyes

it seems an exhaust stud is missing and the exhaust is leaking out of the non tight gap.

Needs a stainless set Neutral

waffles · World Chat Champion Joined: 04 Oct 2009 Karma :

What happened to the gixer? You seem to have had more bikes than I have had hot dinners lately, dude. Glad you tracked down the issue though
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Theory test - 19/8/09, CBT - 11/10/09, MOD 1 - 16/8/10, MOD 2 - 27/10/10
Past rides Yamaha XT125X, Triumph TT600, Honda XR250
Current rides Suzuki GSXR 600, Honda MSX125

P. · Red Rocket Joined: 14 Feb 2008 Karma :