[young gun]

Hi guys,

I don't know if some one can help identify this sound that is coming from my engine, it's been getting progressively louder over the last few weeks. The bike is driving fine with no unusual things happening.

Here's a video:

http://youtu.be/YBkHxsjNNC4

[azcatfan]

Yikes!  Sounds like something is loose in the chamber!  Maybe pull the decomp to see if it's intact.

[High On Octane]

I'm not sure what that is.  Almost sounds like a broken valve spring.  I'd it coming from the front/top of the motor or from the transmission/kick starter area?

Scottie

[young gun]

Decomp?

[High On Octane]

Decompression valve.

[young gun]

Jees I'm having no luck with this bike lately

Scottie it sounds like it's coming from the engine head though it's very hard to pinpoint. This sound started maybe 2 months ago and it's just got progressively louder but it's only there when the engine is hot, i.e in the afternoon after it's been in the sun, in the morning it doesn't make this noise at all which is why I wasn't concerned. These bikes make a lot of clatter so it's pretty difficult to decide whether it's a good or bad clatter

It's going to have to go to my mechanic then. I live in a complex so I'm only allowed to do minor repairs to the bike. Taking it apart is not an option for me unfortunately.

[DonK]

Could be anything.
I had a loud noise start and got louder over time, found out it was piston slap.
Guess you can't really know until you open her up.

[young gun]

Oh and another thing. My starter motor stop working ages ago, as in it would work but not engage, then it just stopped completely. When I press the starter button nothing happens. So I kick start the bike, which it usually starts 1st time. To be honest, I've no complaints with how it's running right now other than the gearbox missing a gear every now and then.

[young gun]

So you rate it needs to go in to the mechanic? It's last service was 1500kms ago, it still had another 1500kms to go.

[Blltrdr]

Hard to pinpoint from video. I would get a stethoscope with a probe from Harbor Freight http://www.harborfreight.com/mechanics-stethoscope-41966.html and check for the location that way.

[cyrusb]

The noise appears to be vacuum actuated? Only happens when the throttle is closed and the engine is decelerating? Am I getting that right? Maybe it is the decomp..

[young gun]

Yup only when I let go of the throttle. I use my decomp daily, I've found no issues with it but it's a good place to start. I thought it may be from where the exhaust pipe joining the cylinder head as that's the kinda locale where the noise is coming from and like you said, it only happens when I release the throttle. Just odd but it's a pretty scary sound, something sounds like it's loose in there.

[cyrusb]

You may be right with the pipe, too. Touch these things with a stick, you may be able to stop-feel the vibrations.

[ace.cafe]

Sounds sort of like an exhaust leak to me.

[young gun]

Ace, Is there anyway to seal the exhaust properly?