Warkton Tornado No.1 wrote:Looking @ the piston, I get mixed messages (probably because of my eyesight!) but it almost looks as though the piston was fitted upside down as there 'appears' to be pegs & ring ends......
As I said, my eyesight, most probably.
That said, the seizure & consequent meltdown was probably due to a soft sieze earlier (that you may have been unaware of) causing ring(s) to stick in the groove which, unless rectified, causes a massive heat build up in the extremely rough area of the piston & bore, leading to the resultant catastrophic sieze.
The other conditions such as burn colour & prior bore condition all look good. The exhaust port could probably have benefitted from being a softer shape, but as the sieze marks & it aren't precisely in line, I doubt it is too wide.
If I were you, I would check the crankshaft, then clean up the bore & even the piston if it is not too bad, & check the resultant clearance. You may get away with new rings. That said, if a fresh piston is required, I would advise that a thin, chrome, two ring piston be sought.
If you do hone it yourself, a really slow drill is required to achieve the correct cross hatch. For that alone, it is worth having the Milwaukee 18v combi drill because the control & torque is ideal.
thanks Mark, if there was a soft seize, I'm too insensitive to notice, although my wife says I have a wonderful touch. Even when it failed completely, it did not seize, it just suddenly stopped producing power, just as if the HT lead had come off.
I tried to get the rings out, but without doing significant damage to the grooves, it's toast, so it's a new one for £60
Which piston would you recommend over an Asso 2 x 1.5m ring?
The friend who recovered me from the side of the road has a honing tool and assures me he knows what he's doing. He is a good engineer, so I'll trust it to him.