Any Thoughts On This?

[100mphlambrettaclub]

lubrication problem me thinks,i hazzard a guess that there is excesive ring ware as well

[cezeta]

on the spiggot side of the inlet there is a white line, is this a camera oddity or is it wher ther is no plating. i was wondering if the shamfer has exposed the ali enough for the two ali matirials to rub?

[soulsurfer]

on the spiggot side of the inlet there is a white line, is this a camera oddity or is it wher ther is no plating. i was wondering if the shamfer has exposed the ali enough for the two ali matirials to rub?

Not sure where you mean. The line you can see running left to right around the bottom of the inlet is the chamfer, it's quite large but I assume this is okay as this cylinder hasn't been touched by anything other than capable hands.

This cylinder has done a few thousand miles now, it had a new piston fitted recently. I also fitted a new carb, after a short while I thought I had piston slap, although I'd done a couple of hundred miles with this piston prior to changing carb. The egt guage highlighted a lean spot when cruising and I assume this is where the lack of lubrication caused the damage?

[100mphlambrettaclub]

what fuel was you using,hats the exhaust side like.

[soulsurfer]

Unleaded from the local Total forecourt. No damage on exhaust sidenits all clean apart from what you can see in the pics, rings look fine too.

[rbgaz]

this usefull info for lookin for cause of piston falure
https://www.slipstreamperformance.com.a ... Path=4_567

[Jet200]

Good link rbgaz. Very interesting