Whiny noise from Lifan 168f

[markymark]

My honda clone is making a quite loud whining/squeling noise whenever I put any load on it, but disappears at certain points during throttle input.

The engine is used to power a homebuilt mini-bike with 22"x10" ATV wheels, the power is transferred through a 2:1 reduction wet clutch -> 11 -> 18 -> 11 -> 56 teeth 428 gears. The reason for the low gearing is due to it being used for travelling in a heavily forested area where a 4 wheel ATV would have been too large and clumsy.

I have no prior experience with these honda clones so I am unsure if the sound is normal or something that can be fixed.

 

[KB2ROCKET]

Is their oil in the reduction box ? It uses the same oil as the engine
Also can we see a picture of your ride?
Thanks

 

[markymark]

These are the bikes, the engines are brand new Lifan 168f-2. The clutches are filled with the same type of oil as the engines.

 

[SAS289]

Very nice bikes. Can you make the noise happen with the back wheel off the ground without a load? Was the noise always there from the start or did it work well then after some ride time the noise started? You may have to pull it apart to see if there is any evidence of a bearing or other reason for the noise. Otherwise everyone will be guessing unless they have had an identical issue. If it were me I would be focusing on the clutch assembly/drive system first.

What's the top speed on those?

 

[KB2ROCKET]

I love the bikes nice job

 

[trinik7597]

If it were a regular clutch I would be focused on that .. since it's a gear reduction setup I would pull it and see if you still have the noise .. if not you k ow it's in your drive

 

[markymark]

The noise exists in both bikes, when the rear wheel is off the ground the sound disappears. The front bike is geared slightly different due to larger tires (25"x12").
Top speed is around 22 km/h. We first ran the small bike without a jackshaft and the top speed was ca 40, the noise was there too.

We tried to cover the inside of the fenders and covers with bitumen insulation and it reduced the noise very slightly.

We will probably open up one of the cases and see if we can find anything odd inside.

 

[trinik7597]

You can isolate this problem very quickly ... Pull the gear reduction off .. if there is no noise it's not the motor .. could be as simple as a wheel bearing but if it does it while stationary probably your drive