Lifan 140 loud rattle! * help *

[MickUK]

Bought a lifan 140 from a guy said it only done 200 miles, Its mint so i beleaved him, He said the valve clearnces might need set as it rattles when you rev it hard.

So i set them at 004 inlet and 006 outlet and filled it out with oil.

Started it up and all i could hear was this really loud rattle, Its either inside the barrel, The head, Or something to do with the exhuast, Or maybe even the sump gaurd, I tryed reving it wilst putting weight on the exhuast with my foot and the sump gaurd but it was still loud.

The bike shakes like crazy i cant put my finger on what it might be, I dont want to take it out a spin incase i blow it up.

ugh.

 

[user 12599]

something like a rock could have fell down into the pipe. Thats what i would pull of first to check

 

[rider456]

the cam sprocket might be loose check that it happend to me. (its under the round cover on the left of the head)

 

[thump*140]

is it a high-pitched rattle, or a low pitched rattle?
High pitched, could be top end bearings, valves etc etc... low pitched, that gets worse as the revs increase, could be bottom end bearings... but that is a very simplistic way of looking at it.
Perhaps try setting the valve clearances at .003 for inlet, .004 for exhaust... you may have a bit too much of a gap with the settings you have...

 

[MickUK]

Checked that rider, Its tight, But when i put the cam to TDC i can hear a blowing noise, Like there is air getting past one of the valves at TDC?

Would this cause a loud rattle?

 

[thump*140]

more likely that air is getting past the rings... poor ring gap perhaps? may be a case of pulling the top end down, and seeing what you are up against... might have a shagged top end?

 

[roost666]

just rebuild it for piece of mind, your gunna have to pull it down anyway so might aswell while your there ay

 

[MickUK]

more likely that air is getting past the rings... poor ring gap perhaps? may be a case of pulling the top end down, and seeing what you are up against... might have a shagged top end?

Getting past the piston rings?

I can only hear it when i take the cam sprocket cover off, would a valve leak air?

I bought this engine today and the guy said it was running 100% but came out of a crashed monkey bike, i might just take it back.

 

[thump*140]

yeah rings arent one un-interrupted circle... if the gaps arent right, or the rings are worn, air *can* sneak past them on compression stroke.. leaks down into the crankcase, blows out of crankcase breather... i'd be taking the motor back if it was sold as "100%"... clearly it isnt... take it back, buy a new one for a $100 extra..

 

[MickUK]

Im putting a vid on youtube now, Let me know what you all think it could be.

 

[MickUK]

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[coolmodee01]

the timeing is out and the piston is hitting the valves

thats what it sounds like any way probablry only 1 tooth but it's enough to do damage

 

[MickUK]

the timeing is out and the piston is hitting the valves

thats what it sounds like any way probablry only 1 tooth but it's enough to do damage

Ok so take the sprock off and move it up 1 tooth?

Is the damage already done should i even bother?

 

[bulldog93]

1)take the flywheel cover off and the camsproket cover off.

2)on the flywheel there will be a mark called "T" line that up at 12 0'clock( there'll be a mark to line it up with)

3)line the camsproket up at 9 o'clock (there will be marks aswell to line up)

 

[MickUK]

1)take the flywheel cover off and the camsproket cover off.

2)on the flywheel there will be a mark called "T" line that up at 12 0'clock( there'll be a mark to line it up with)

3)line the camsproket up at 9 o'clock (there will be marks aswell to line up)

Did that just now, Everythings how it should be, Ugh what could this be.

 

[bulldog93]

sounds like something is slaping againts another thing or somethings loose.....

 

[coolmodee01]

yeah mate by the sounds of it you should be ok it wouldn't run if to much damage has been done

and the timing mark can be deceiving on the cam it will be set right but the mark on the cam will be above the mark on the head but only just this has to do with timing advance and retardation
if the mark on the cam is below the mark on the head it will be a tooth out and cause this issue

check it and see how ya go

other things could be loose timing chain or your oil slinger could be loose and rattleing around could also be the stator hitting the pickup.

 

[MickUK]

yeah mate by the sounds of it you should be ok it wouldn't run if to much damage has been done

and the timing mark can be deceiving on the cam it will be set right but the mark on the cam will be above the mark on the head but only just this has to do with timing advance and retardation
if the mark on the cam is below the mark on the head it will be a tooth out and cause this issue

check it and see how ya go

other things could be loose timing chain or your oil slinger could be loose and rattleing around could also be the stator hitting the pickup.

Do you advise going foward or backward 1 tooth?

 

[coolmodee01]

with out looking at it i dont suggest anything throw up a pic of where the timing mark is atm

then i'll suggest something dont wanna wreck ya motor on ya

 

[MickUK]

with out looking at it i dont suggest anything throw up a pic of where the timing mark is atm

then i'll suggest something dont wanna wreck ya motor on ya

Will do that now mate.