Norton Follies!
- Thread starter pierodn
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Piero,
Which confirms my suspicion even further, the pistons have either been previously used in this engine which suffered damage and then been repaired with the pistons re-used, or they have come from another engine and used in this engine, may have even suffered as Jaydee75 has indicated. For a piston crack to propagate in the direction shown seems to suggest it started cracking on a surface near to the small end of the con rod and propagated sideways and upwards, if it was from the outer edge of the piston I would expect it to meet the ring groove on its path of travel and either terminate or follow the groove. All this is indicating they have been fitted by someone who did not know what they were doing.
What is certain - they are scrap - both pistons, and the person riding this with the pistons which I believe were poorly fitted / should never have been re- fitted, has had a caring guardian angel flying alongside him.
Follow the advice from the others who also suggested that a close critical inspection of all the parts including the cases is carried out, and you will have confidence in what is left to re-assemble the engine using replacement parts where needed
Which confirms my suspicion even further, the pistons have either been previously used in this engine which suffered damage and then been repaired with the pistons re-used, or they have come from another engine and used in this engine, may have even suffered as Jaydee75 has indicated. For a piston crack to propagate in the direction shown seems to suggest it started cracking on a surface near to the small end of the con rod and propagated sideways and upwards, if it was from the outer edge of the piston I would expect it to meet the ring groove on its path of travel and either terminate or follow the groove. All this is indicating they have been fitted by someone who did not know what they were doing.
What is certain - they are scrap - both pistons, and the person riding this with the pistons which I believe were poorly fitted / should never have been re- fitted, has had a caring guardian angel flying alongside him.
Follow the advice from the others who also suggested that a close critical inspection of all the parts including the cases is carried out, and you will have confidence in what is left to re-assemble the engine using replacement parts where needed
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I had a cracked piston in a Triumph and I think it started at the top edge through detonation and headed for the gudgeon pin hole. The edges of the crack on the piston top certainly were old and eroded looking.
I don't know if a crack can start at the gudgeon pin hole, but it can certainly stop there. Until the crack travels to the other gudgeon pin hole and the piston flies into pieces. The OP has at least avoided that.
I don't know if a crack can start at the gudgeon pin hole, but it can certainly stop there. Until the crack travels to the other gudgeon pin hole and the piston flies into pieces. The OP has at least avoided that.
Madnorton said:
Hi.
I mean.
The engine will be rebuilt with two new superblend FAG bearings, new conrod shell -.10, new +0,20 pistons (rebored crankshaft and barrells).
The conrods are very stright and the cam is like new; the head/valves will have a carefull inspection.
I will change the gearbox layshaft bearing and what needs else.
I always open and rebuild all the engine/gearbox of the bikes that i buy, even if they run well and i knowh where they come from.
But as you know from the pictures i have posted, this is the strangest bike i have never had and seen before; the right case, at the timing/blanking plate side was cutted off!!!!!! (i will weld the part because i want to keep the stock matching cases).
It would be very very interesting to know why?
It will remain a mistery but this bike will come back to be a nice SS as she left the England to arrive in Italy in 1971.
Merry Christmas.
Ciao
Piero
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