Excessive Whirring Noise? Dax 70cc



Hello, new rider, have a dax 70cc on a mountain type bike. All hooked up, started fine, running OK for a new motor with only about 12 miles on it. The one thing I noticed right away was not the exhaust noise but a whirring type noise. I found removing the plate covering the clutch helped a lot, as it seemed to amplify the sound. I still hear this whirring noise and it sounds odd to me. I lubed the gears with some white litheum grease and I see no wearing etc. Not sure if this is from the clutch or what. Any ideas? I would like to put the clutch cover plate back on as well. Hard to know what is normal, or due to break in etc. as this is my first experience with it. To give you an example of the noise level of this "whirring" with the cover plate on - I could hear it much more than the rest of bike/motor as my son drove down the block.

Another quick question - I live at an altitude of 3500 feet - ideas for best setting for carb?

Topher Dax 70cc
I have no advice, but I noticed the same thing about the clutch plate cover. I drove my bike with the cover off the last time I lubed the gears and it did make that metalic sound level go way down. Maybe we should make gaskets for the clutch and sprocket cases to dampen any resonance.
I agree, I think the cover is acting like a drum, even off the bike, if you run a finger nail or a tool etc. it seems to amplify the sound. Thinking about gluing a piece of cork etc. on the plate to help absorb the sound - have to make sure I clear the clutch. Still seems to make a bit of noise - maybe it is normal.

The whirring noise you're hearing is the reduction drive gears (the gears on the crankshaft and around the perimeter of the clutch). They're cheap, straight cut gears so they'll always whine. Just something you have to live with. They may quieten a bit as they break in.

If your carb is like most of the Chinese engines the only adjustment other than idle speed is to raise or lower the fuel metering needle by moving the e-clip to a different notch. The ones I've seen have 4 notches and are usually shipped with the clip in the second notch from the top. Moving the e-clip to a higher notch leans the mixture.
Topher...read your welcome PM again, then go introduce yourself like you would in real life. also, please note we highly recommend using the search before starting a new topic about such basic stuff.
They make a sound deadening material that can be glued to the clutch cover that reduces the noise by about 50%. I did it to my bike and it helped a lot. Putting it over the output shaft cover on the left side helps too. You can use products like Dynamat but it is really expensive. I would try and find a local plastics shop and see if you can get a few scrap pieces of Kydex or similar rubberized sheet plastic.
Thank you, I will do just that.

FYI - I looked through a lot of pages looking for a similar whirring noise issue and did not find anything specific.

I will intro myself in the New Member section soon.
I had same issue with my new Dax 70 today. I fixed the whirring noise by gutting the exhaust. Problem fixed.