Knacked piston (pics)

[Gaz]

Mates standard lambretta 125cc had poor compression and was not firing, not a cough,fart, nowt, even though it was sparking and getting petrol through, so dropped the engine and stripped the top end to find the piston clip had snapped and caused scoring and a ring to seize in.

Here's the question would this be enough to cause no firing? Had compression issues snapped rings etc on other scoots and always seem to get them to at least fire up albeit sounding rough.






Thanks in advance

[bristolmod]

thats been blowing thru before the ring issue, so the compression was pretty poor prior to the breakage- the final straw appears to be the broken ring and scoring.

Basically, yes, poor compression will cause the engine not to fire.

Chris

[kevspeed]

By the look of the pictures,its 'fecked',a re-bore and a new oversize piston look to be in order,not firing due to lack of compression!

[Norrie Bodge]

Yep had it on a perfectly looking 200 barrel yrs ago, not 2-bad on compression
Sparking like fook but just wouldn't fire-up?

Rebored & sorted

[Gaz]

Thanks everyone! He is gonna go for a new top end now rather than a rebore.