Snapped Crank!

[Zirtech]

brand new 6 hour old lifan 140cc 1p55fmj 100% dead stock...nothing touched

pics speak for themselves

 

[jakey]

ouch warranty?

 

[Hillz]

to much power!!! haha they don't make coke cans like they use to..

but serious thats gotta suck dude hope they warrenty that for ya

 

[themountain]

well...take it back where you got it!!...thats a warranty issue

 

[Zirtech]

i know its warrenty is all been done...purely reporting engine failure and giving guys a reference in case anyone ones one

 

[themountain]

**** can happen !!...with all stuff

 

[Fiddy@norway]

is this a common failure on stock Lifans?

 

[Fastbastard]

Is this the Daytona copy, type lifan engine?
More pics please.

 

[coolmodee01]

no it's not^^^^^^^

but my mates 125 did the same thing in bout 2 weeks

china for ya

 

[Zirtech]

been put down to either a poor crank...hair line cracks or airbubbles in steel

or a missbalanced flywheel

(THIS WAS FROM THE MECHANICS FROM THE SHOP THAT SOLD THE MOTOR)

 

[SnItChY]

id put that down to

**** happens ,seen worse on bikes and seen a piston blow apart on a new out of the shop kwaka ,as said **** happens ,were all human ,hence warranty

thanks for the pics

 

[Cactus Jack]

been put down to either a poor crank...hair line cracks or airbubbles in steel

or a missbalanced flywheel

Out of balance flywheel or the crank halves weren't trued properly meaning the crank end was running out ... which has caused it to crack near the bearing where they probably have a small step which forms a stress riser ...

On reading the failure you can see that it has cracked from the outside in due to rotating bending stress ... The twisted circular area is known as the "instantaneous" zone where the flywheel side has tried to hang on but couldn't due to the flywheel orbiting and flexing/bending the crank end ...

Forget the dope assed "air bubbles" in the metal crap ... People make me laugh when they say that garbage ... Sheer intelligence tells you that IF there were air bubbles in the metal then you'd see them in the surface texture as well ... The rough brittle looking surface is quite normal and shows that the break wasn't caused by shearing or torsional twisting since the metal would be smooth with shiny rub marks in that case ...

I'd say what we have here is a "green" (unseasoned) crank that has been subjected to too high revs too early coupled with an out of balance or run out factor ...

 

[Zirtech]

was subjected to too higher revs too early????

i didnt make up the air bubbles thing the importer did...

i suggested an out of balance flywheel...

the crack is EXACTLY directly on the outside of the cam chain sprocket on the crank

i noticed the spiral...i friend suggested a hairline crack in the crank from factory and the weight of the flywheel causing the split

regardless of what happened its nothing as a rider anyone could have done

 

[Cactus Jack]

Regardless of what caused it ... I'd say if it happens again the seller won't replace it ...

 

[cass38a]

My lawn mower snapped the crankshaft and chucked the whole boss and blade assemby out the bottom just this morning. I should post up a picture of the crank for Cactus to keep him busy. BTW a new briggs and stratton Quattro engine is worth $240, will take a week to arrive, my lawn is only half mown (looks crap) and we have had so much rain this week that the new engine will cop a hiding on it first hit out.

 

[I_THUMP]

My lawn mower snapped the crankshaft and chucked the whole boss and blade assemby out the bottom just this morning. I should post up a picture of the crank for Cactus to keep him busy. BTW a new briggs and stratton Quattro engine is worth $240, will take a week to arrive, my lawn is only half mown (looks crap) and we have had so much rain this week that the new engine will cop a hiding on it first hit out.

Should have bought a Lifan mower LOL

NEW BBT LIFAN 5HP SELF PROPELLED LAWN GRASS MOWER - eBay Outdoor Power Equipment, Tools, Gear, Equipment, Gardening, Lawn Care, Home. (end time 06-Oct-08 21:00:00 AEST)

Seriously though the briggs and stratton motors are good quality and are right up there with Honda imo.

 

[topguntravis]

where did u get the engine from?
i'm ganna rebuild my engine before warranty goes on my bike now so i can get free parts if they are stuffed up.
how did u notice that it had happened? when u were riding?

 

[cass38a]

Should have bought a Lifan mower LOL

NEW BBT LIFAN 5HP SELF PROPELLED LAWN GRASS MOWER - eBay Outdoor Power Equipment, Tools, Gear, Equipment, Gardening, Lawn Care, Home. (end time 06-Oct-08 21:00:00 AEST)

Seriously though the briggs and stratton motors are good quality and are right up there with Honda imo.

Another Honda Rip off, You seriousley consider this type of mower compared to the side valve (yes that is side valve like a 1920's engine) Briggs and Stratton.

 

[cass38a]

where did u get the engine from?
i'm ganna rebuild my engine before warranty goes on my bike now so i can get free parts if they are stuffed up.
how did u notice that it had happened? when u were riding?

I am pretty sure you would "notice" your crank giving up within a milisecond of it happening.

 

[I_THUMP]

Another Honda Rip off, You seriousley consider this type of mower compared to the side valve (yes that is side valve like a 1920's engine) Briggs and Stratton.

The Lifan comment was a joke but I do consider the Briggs and Stratton to be a top lawn mower motor. Ive never had any problems with mine and it spends its time out in the weather all year round lol and starts first time every time. Goes through everything too