Odd sound and smell

[sboricic123]

My 66cc china girl started making some weirds noisess like a popcorn machine or grinding sound. Plus it has an odd odour. I'm not sure if the odour is from the exhaust after switching oil brands. I'm running it at 50:1 with Amsoil. Any hints would be helpful as to what it could be.

 

[crassius]

engage your clutch and push the bike forward & back a few inches - you will hear a clanking sound from the backlash of the clutch gears

when the engine is running with the clutch disengaged, the piston turns the crank when the plug fires, while the crank pushes the piston beween firings

with the clutch engaged and riding at speed, the weight of the rider causes the momentum of the rear wheel to push the piston faster than the crank does - this takes up the slack in the gearing, such that at higher revs you hear that backlash clank a lot at a rapid tempo

this is not something to worry about

as far as the smell goes, look for wires, muffler paint, or your pant leg getting burned by the heat of the muffler

 

[sboricic123]

I should add too that it does it if I'm stopped or moving. It still starts up fine.

 

[crassius]

in that case, it could be as simple as the clutch dragging a bit or something really serious

look for leaks at gasket seams and try to find where noise is coming from with a stethoscope or a long screwdriver between your ear & engine

 

[MotorBicycleRacing]

My 66cc china girl started making some weirds noisess like a popcorn machine or grinding sound. Plus it has an odd odour. I'm not sure if the odour is from the exhaust after switching oil brands. I'm running it at 50:1 with Amsoil. Any hints would be helpful as to what it could be.

grinding?
did you take off all the covers and look for the source?

rotate the engine with the chain disconnected?

 

[sboricic123]

I have adjusted the clutch but that's all for now. The noise seems to be coming from the engine itself even when idling. Perhaps the pistons or something are on there last limb?!

 

[sboricic123]

I removed the flower nur and clutch cover and noticed the pads are quite worn out causing the plate they rest in to rattle and loose. Is that common for the plate to be loose? Could that be the noise and odour from burnt pads that I have noticed?

 

[crassius]

yes, it will be loose without the flower nut - seals a bit too tight for smell to get out I'd guess tho

 

[2door]

Start here > http://motorbicycling.com/showthread.php?t=22726

If the smell is like burning rubber it is the clutch friction pads. My guess would be the clutch cable is too tight allowing the clutch to slip. Either that or you are slipping the clutch when you try to take off from a dead stop. You must pedal up to speed, about 10 mph before releasing the clutch. Remember, it isn't a motorcycle.

If you didn't adjust the flower nut properly the clutch might be slipping. We always suggest getting clutch cable tension right before messing with the flower nut. They are usually adjusted correctly from the factory.

Another thing that will cause your problem is over lubrication of the gears on the right side. Too much grease will end up on the clutch making it slip and smell.

Tom