Trouble shoot engine sound - New video added

[mmaxima]

Update 11/06/12
I replaced the auto choke, bystarter and it fix the starting problem. The bike will start right up without throttle now.

Ever since I got my 2007 people s 250, I've been trying to identify the weird engine sound. I always need to give a little throttle to get it to start when the bike is cold. It will not idle stable. I've play with the idle screw, replaced the gas filter and spark plug. I also clean the carb. The battery is in good shape. The next thing I'm going to do is to replace the auto choke, bystarter. I've attached the video that has the engine sound. I was hoping someone can help me trouble the problem. Thanks.



New video added. Transmission case removed.

[gregspeople250]

My People 250 idles much faster than that at cold start.  Hopefully, it's just a low idle or the bystarter has failed.

[Pimpy1]

That sounds like an exhaust leak. Also check for hole on vacuum hose coming off the top of the carb. Just under the seat bucket. It can get pinched there.

[mmaxima]

I've heard people saying it's possible the belt hitting the transmission casing. I'll open it up this weekend and find out if that's true. Some people has complain that one of the screw on the upper right corner of the casing is terrible hard to unscrew. I was able to use a 8 mm wrench to loose it and use my hand to remove it. Take me 10 minutes. And I don't have to remove the seat like others did.

[gregspeople250]

That's not the belt making the sound; it's the sound of a very low idle.
Have fun and be sure to use assembly lube on the fasteners when you reassemble and torque to spec's in manual.

[Rudolf]

I believe it's the timing chain rattling. The Grandvista (Grand Dink) and People 250 have the same type of engines. Mine had a worn timing chain and was flapping around inside the engine only at low RPM. I have a video with my bike running having the CVT removed and before changing the timing chain: and here is a video after i've changed the timing chain:

[Rudolf]

That's not the belt making the sound; it's the sound of a very low idle.
Have fun and be sure to use assembly lube on the fasteners when you reassemble and torque to spec's in manual.

Try running the engine with the CVT and belt removed and see how it sounds.

[naughty lee]

That sounds like an exhaust leak. Also check for hole on vacuum hose coming off the top of the carb. Just under the seat bucket. It can get pinched there.

I'll go with that, put your hand in to where the exhaust mates against the engine ( with the engine running but not red hot) can you feel a draught of exhaust gas ?

I'd also increase the idle speed by a 1/4 of a turn