I am probably going to have to split the cases , as the saying goes . So I used a camera probe to check out the cylinders and this is what I have in my 77 supersport . I should have a rounded dome piston , yes ? And this bad boy has 4.0MM stamped on it . Unfortunately this is the only readable piston as the others are all carboned up . There is a brand ( I think ) above above the sizing stamp , but it is almost impossible to read . I think I can see a H in it ........ but ? So does anyone recognise this type of piston and or what the size stamp means please
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Can you ID these pistons ?
- Thread starter hinksy
- Start date
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- Tags
- build thread sohc
Definitely look aftermarket. Manufacturer is more than likely cast into the underside of the piston. 4mm oversize would make it a 836cc
Thanx for that , seems I got a big bore . Bet you any money it wasnt done properly
836 will live fine in a stock motor with stock internals. Only thing that needs to be done is boring the cylinders. By the look of the carbon on the pistons it looks like it has some miles on it. Depending on the ring widths it may be hard to find replacement rings but a ring company may be able to match them up. Depending on how bad the bores are worn will determine if you can reuse the pistons. If worn you would have to find another cylinder and have them bored for the pistons.
The speedo says 27 000 mile , So who knows . I dont know yet how far I will have to go . Once I pull it down I will know . By the look of the bores it will need a hone at least and the valves have been leaking for some time , so with what looks like rusty rings , the pistons look like shite
Tops can easily be cleaned...it what the skirts look like that matter. I would say there is a lot of hard use on it looking at the lack of crosshatch. Probably going to have worn out cylinders by the looks of it. Looks like it was an oil burner or the fuel was really bad.
