Disposable bike (Chinese) engine noise problems

[Skidmarx101]

Hello,

Got my chinese bike last week, took at out for its first run today. All went well apart from a slight noise in 2nd, and a similar noise but much louder in 3rd (1st & 4th ok). The noise is so bad I avoided using 3rd because its nasty..... like the piston hitting something (don't think thats what it is).

The motor says Hong Yuan on the side, its got the 4 down gearbox (don't really like), the sticker kit I got says Demon Bike and the swingarm is steel, oh and its 125cc.

To me (not really familiar with bike engines but not stupid) I think theres something wrong in the gearbox. Anyone seen or heard of this before, or any ideas?

Cheers

 

[lo-cou]

did u run it in properly?,must be a early model demon,my demons got a loncin 125cc with 1 down 3 up gearbox.

 

[Skidmarx101]

Maybe or maybe a rip off Demon? I was running it in, not going too hard but if the run in was the prob then 1st and 4th would make the noise as well?

4th goes fine, speed pickup is good.

 

[crazzy #1]

i dont realy like loncins... as all the ones i have had overheat

 

[Redstar]

A friend of mine's complainin' about somethin' similar, but in 2nd and 3rd gear. Unfortunately, I wont be able to let us all know what it might be as he'll be out in the next couple of weeks. When we find what it might be, I'll add it here.

It's a 125 Loncin, by the way.

 

[Skidmarx101]

Thanks Redstar.

Mine is 2nd & 3rd also, sounds like the same problem. My engine say's Hong Yuan on the side?? Could it still be a Loncin, how do I tell?

Let me know how it goes!

 

[Vindac]

Hey,

Did u change the transportation oil & undo rear engine breather hose.

 

[Skidmarx101]

The breather hose was shipped unclipped/unblocked. It was the first time I used the bike so I left the transportation oil in, planning on changing after the first run.

Will change oil and double check breather hose.

Cheers

 

[Vindac]

Yeah, id change that transportation oil really quick, my mate stripped his gears using the original oil, its like rice oil or something, get it changed asap.

 

[Skidmarx101]

I'll change the oil tonight and let you know.

Thanks

 

[Redstar]

Good call Vindac, I thought about the same thing.

Dont go synthetic oil as of yet skidmarx101.

 

[sixeven]

Forget the oil guys. the motor is fingered. 2nd and3rd gears ALWAYS FAILon chinese bikes. Just do what the name suggests and dispose of the thing and buy another disposable bike or just replace the engine. Keep replacing the motor till you get one that doesn't break. There is no real solution to the problematic gearboxes in chinese bikes. They need to stop making them out of cheese.