Lifan 125 smoking.....
- Thread starter G-Force
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Satchy
Well-Known Member
Yeah mate got my cash on the oil ring.... New set of gaskets and Piston with rings should set you back no more than $60.
Then youll have yourself a fresh engine.
Then youll have yourself a fresh engine.
headsmess
Miniriders OG
it will be either rings, head gasket, or leaking valve stems... start at the top... take head off(about an hour....ten minutes if you do it often enough
). if the gasket looks ok, then change the rings(and head gasket). if it still smokes, after all that...then its the valve guides.
and get the cylinder honed when you do the rings... in fact, you might have to get it rebored to the next size up, if its overly worn.... while the heads off, its worth regrinding the valves...
alloy or cast iron cylinder? lifan....cast iron more than likely...
). if the gasket looks ok, then change the rings(and head gasket). if it still smokes, after all that...then its the valve guides.and get the cylinder honed when you do the rings... in fact, you might have to get it rebored to the next size up, if its overly worn.... while the heads off, its worth regrinding the valves...
alloy or cast iron cylinder? lifan....cast iron more than likely...
Shing
Well-Known Member
Isn't iron better anyway? Or is that iron piston?
Something to do with the way that the iron absorbs heat compared to alloy?
Something to do with the way that the iron absorbs heat compared to alloy?
headsmess
Miniriders OG
iron is better for various reasons.
stronger. less likely to distort under heat. the carbon(graphite) content produces a"self lubricating" surface. the porousness holds a small amount of oil. the surface tends to "work harden". chrome plated 2 stroke cylinders are crap.
and... alloy cylinders still have cast iron sleeves...just the thickness of it is crucial.... i wouldnt touch an alloy BBK for that reason... even if they do look sorta cool...
cast iron piston? wow, someones got an old 1900 hit n miss industrial engine fetish...dont rev over 1000rpm
cast iron is brittle. only downside.
stronger. less likely to distort under heat. the carbon(graphite) content produces a"self lubricating" surface. the porousness holds a small amount of oil. the surface tends to "work harden". chrome plated 2 stroke cylinders are crap.
and... alloy cylinders still have cast iron sleeves...just the thickness of it is crucial.... i wouldnt touch an alloy BBK for that reason... even if they do look sorta cool...
cast iron piston? wow, someones got an old 1900 hit n miss industrial engine fetish...dont rev over 1000rpm
cast iron is brittle. only downside.
iRide4life
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my friend has a lifan 125cc engine it started blowing heaps of some so he took it to a mechanic(change rings) for a 100 bucks (engine was about 2 months old) he got it back started riding it again same thing started up again bout half an hour in.
I told him to check his oil and he had been riding with half the capacity of oil and it was black and dirty so now hes up for a new engine he said about 380 bucks it will cost him new and installed.
I told him to check his oil and he had been riding with half the capacity of oil and it was black and dirty so now hes up for a new engine he said about 380 bucks it will cost him new and installed.
pbk
Well-Known Member
wats the compression like is it heaps easy to kick over never kicking back or on the rare occasion?? rings wear tthen more than likely rings coz as the rings wear there is a slight gap between rings and bore sleeve whatever you wanna call it so as it compresses the air some of it goes behind the piston therefore loosing the compression, also does it seem like it has lost power?
Cactus Jack
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iRide4life's mate took his engine to a bodgey "mechanic" (IF that's what he thinks he is) ... LOL ... You have to re-hone the cylinder when fitting new rings otherwise you're wasting your time ... The honing beds the rings in again ... Without the re-hone , the engine will blow smoke straight away ... Any decent mechanic would have changed the oil for a start ...
When rings wear the end gap gets bigger and allows compression and oil to escape ... IF the ring end gaps aren't staggered properly the engine will blow smoke straight away ... Even if you remove the piston from a good sealing cylinder then put it back in without changing the rings and re-honing ... the engine can blow smoke ... The rings can easily be stretched if removed from the piston then put back on and even brand new rings can be easily stretched when installed by someone who doesn't know what they're doing ...
IF it's the rings gone , the engine will blow more smoke as it's revved ... IF it's just leaking valve stem oil seals , you'll see a puff of smoke on start up which will go away as the revs are increased ... but you'll see a small puff every time you back off in gear and hit the throttle again ... That's because when you back off the cylinder vacuum sucks oil past the inlet valve stem seal , thru the guide and into the inlet port ...
When you re-hone and fit new rings you have to go thru the ring bed-in procedure to get them to seal properly again ...
You can buy complete new cylinder , piston , ring and gasket kits for stock engines fairly cheaply ... I think East50's sells 'em ...
When rings wear the end gap gets bigger and allows compression and oil to escape ... IF the ring end gaps aren't staggered properly the engine will blow smoke straight away ... Even if you remove the piston from a good sealing cylinder then put it back in without changing the rings and re-honing ... the engine can blow smoke ... The rings can easily be stretched if removed from the piston then put back on and even brand new rings can be easily stretched when installed by someone who doesn't know what they're doing ...
IF it's the rings gone , the engine will blow more smoke as it's revved ... IF it's just leaking valve stem oil seals , you'll see a puff of smoke on start up which will go away as the revs are increased ... but you'll see a small puff every time you back off in gear and hit the throttle again ... That's because when you back off the cylinder vacuum sucks oil past the inlet valve stem seal , thru the guide and into the inlet port ...
When you re-hone and fit new rings you have to go thru the ring bed-in procedure to get them to seal properly again ...
You can buy complete new cylinder , piston , ring and gasket kits for stock engines fairly cheaply ... I think East50's sells 'em ...
