2T/Gas Gas Newbie Question

[phoenix]

I have only ridden four strokes and my 2013 Gas Gas 300 is my first foray into the two stroke world. With that being said, there is a noise that comes from the bike that makes me curious. It sounds like when you open your throttle and let it slap shut...like the slide on the carb whacking shut. It happens when I'm on the gas, though, not necessarily when I close the throttle. I'm sure you're all snickering because its something obvious, but can anyone enlighten this 2T newbike as to what the noise is (and is it something to worry about)?

 

[Jakobi]

*snicker snicker*

They are pretty noisey engine. Its hard to know exactly what you are hearing though. The PV is a very basic design which needs clearance to allow for carbon build up. This will 'clack' as it rattles a bit. Its more common in the lower rpm. You'll probably also want to check the preload on the PV plate from the actuator arm. Some are a bit slack from the factory and you'll pick up some bottom end performance by getting it right.

It could also be excess fuel being burnt off in the pipe. Its not uncommon for them to knack a bit at part throttle or when letting off from higher rpm.

Does it happen on the stand or when you're riding?

Other strange sounds that you might hear are the pipe springs/header vibing against the spigot. The bashplate vibing against the frame. I even get the brake pads rattling against the disk when they wear out. Any chance you could post a video?

 

[andoman]

Check for PV Slop

Exact same sound I had. Tightening up the PV linkage all put eliminated the sound. I didn't really put any pre-load on it, but just took out the slop. There is a great pinned thread on the subject.
I'm with Jakobi on the other sounds for overall annoying "noisiness." Quiet the singing exhaust springs with a short length of tubing slipped over each one. At the earliest convenience toss the stock exhaust o-rings for viton units.

While we're talking exhaust: I isolated some vibs from engine to frame by cutting about 5/8" off both the exhaust stinger and the lower end of the silencer pipe. My silencer pipe doesn't slip into the stinger any more. There is about a quarter inch separating them inside of a 3 1/2" length of heavy duty heater hose. The exhaust pipe and silencer are both free to move independently.

 

[phoenix]

Thanks to both of you. I've mostly noticed it on straightaways when I get on the gas but then let off the throttle a bit. It doesn't seem like a vibey noise...more of a clack. I'll find that article about the powervalve and shoot a vid if that's not the culprit. Thanks for the other noise tips as well.

 

[bowhunter007]

once you identify the little noises that go along with your new bike, you'll only really notice them...when they stop.

 

[Jakobi]

I broke my front pipe mount off yesterday! Its noisey now.

 

[LAWMAN]

sounds like the dreaded "power valve clack" to me. I wouldn't worry about it unles it stops....

 

[roostafish]

With the Q Stealth, every little mechanical noise is accentuated. With my new bike, all I hear is booming noise from the muffler. It's not that loud, but it's a heck of a lot louder than a two stroke with a Q Stealth.

 

[desertgasser300]

sounds like the dreaded "power valve clack" to me. I wouldn't worry about it unles it stops....

My 12' is now doing this, it's more of an anoyance then anything.