metal on metal noise

[lukasd2009]

The engine runs, I know its not the cain making the noise because it is still there when I am at a stop with the engine idleing. I took of the cover on the right ( looking from above ) and saw that when I pulled down the clutch and rolled the bike around I could see the big gear wobbleing a little. That is one problem, the other being that the small gear is screwed down to tight and I can't get that screw out to make sure the woodruff key is all good. Like I said it runs, but makes a horrid noise, and I get the feeling there is some friction that is there that wasn't before, i feel it wanting to decelerate faster when i let off the throttle.

 

[bluegoatwoods]

It might just be the noise that happy times make. They really are noisy. (it's a pity)

but you've given a clue or two that maybe there is something wrong. So I'm not gonna be much help here.

But they do make a lot of noise. Hopefully that's it. Good luck.

 

[arceeguy]

Pop on to youtube and search for "80cc bicycle engine", watch some of the videos and listen to the engines. Once mounted on a bike, these things produce a cacophony of sounds, some of which don't sound too healthy.

Chances are, if there isn't a rhythmic rapping/tapping/banging sound in sync with engine RPM, you are probably fine. Most of the noise I hear on mine are the chains and fenders vibrating. It seems a lot worse sitting on the bike than it does from 10 feet away, where it sounds a lot more quiet.

 

[Egor]

I recently had a noise that I did not like and it turned out to be the rod and bearing on the left side of the engine. I removed the cover that is over the sprocket and took out the rod and ball that are there to lift the clutch. Pushed a lot of good grease down the hole and pushed the ball and rod back in, I also added grease to the lifting cam in the outer cover and the noise was gone. When it started in the beginning I had a feeling that it was that part, but when it did it with the clutch out I thought no way, but pulled the cover any way, yep the grease they use is to look like grease so you are fooled to think it is. Any time you see there grease replace it, its not grease. Put some real grease on those gears - Oh I have one of my engines that wobbles too. Have fun, Dave

 

[Rain City]

lifting cam? my clutch is making more noise than i'd like, i even have the cardboard mod goin on

 

[Bronzebird]

Check the bottom exhaust screws and tail pipe it self. I had to put allen head screws, lock washer and nylocks to stop loose screws on exhaust bottom. NO loose parts or it will sound bad. (I mean worse...Ha-ha)