Sharp crack-like noise at 4500rpm

My bike (SVSK4 ~2000miles) recently cut out (not sure why but hasn't done it since ) and so after getting it re-started I slowly twisted the throttle round a few times to make sure it wasn't going to die again. As the revs get to 4500rpm, it makes a sharp 'crack' noise. Similarly, when releasing the throttle, as the revs pass through the 4500rpm mark, it makes the same sound. I've been kind of aware of it for a while whilst riding but never got round to investigating

Anyone got an idea of what this might be? I've read the cam tensioner posts and it doesn't sound like this is the cause since it's not really a rattle. It sounds more like a (powerful!) solenoid opening/closing - certainly sounds like metal-on-metal, anyway

Thoughts please.

Cheers.

You sure it's not bodywork resonating suddenly at a harmonic frequency? Try grabbing parts of the bodywork as you raise the revs to see if you can track it down.

I'm fairly sure it's not resonance or vibration since it only does it the once. I'll give it a go though...

I'll also see if I can hold the throttle at the exact point it makes the noise, although it does seem like a binary thing, making a clunk as something switches when the revs move past the 'magic' rpm. There's no extra engine gubbins that come into play past a certain point is there

Not trying to be really stupid, but have you checked your spark plug. I had a problem with my spark on my old scooter and it caused this incredible noise.

For those not yet bored

I've not checked the spark plug *but* I did try and hold the throttle at the revs that it clanks at and it's definitely an on/off thing. Had a (technically-minded!) friend also listen and he reckons it sounds very like a solenoid too. Will have another look tomorrow but it seems to be in the general vicinity of the front cylinder throttle body.

Maybe I'll see how good the warranty is and try to get the dealer to check it for free....

[embee]

I'm sure this exact same thing has been mentioned before a few months ago.

My SV is a carb jobbie so I didn't pay all that much attention and can't remember what it was, but a solenoid valve sounds familiar.

I know this is easy to say, but it's a K4 - It's still under warranty - take it back to the dealers & let them sort it

Originally Posted by Cloggsy

I know this is easy to say, but it's a K4 - It's still under warranty - take it back to the dealers & let them sort it

"but it's a K4 - It's still under warranty - take it back to the dealers & let them sort it"

Yep, you're right, it is easy to say.

Originally Posted by Muttley

"but it's a K4 - It's still under warranty - take it back to the dealers & let them sort it"

Yep, you're right, it is easy to say.

"but it's a K4 - It's sitll udner wrratnay - tkae it bcak to the daerels & let tehm srot it"

Are you sure... I struggled myself!!

Originally Posted by rukus

"but it's a K4 - It's sitll udner wrratnay - tkae it bcak to the daerels & let tehm srot it"

Are you sure... I struggled myself!!