Pistons, rings bores etc
Posted: Sat Aug 18, 2012 11:57 am
First of all.
Gaaaaaaaaarrrgghhhh!
Got a set of new piston rings in the post with head and base gaskets etc when I was contemplating re-using the old piston.
Fitted them to the bore to check the end gaps, the end gaps were immense, I could measure them with the external prongs of the vernier calipers!
Thought, this just doesn't seem right, checked diameter of an old ring and the new with the gap closed up, the old ones are bigger.
Dug out the old first head strip pics and had another closer look at the piston crown, (I don't have internal micrometers and the only external I have is a narrow range so measuring said bore and piston accurately is not possible), on the crown under magnified inspection the bit that I thought said T040 looks like +040, (makes more sense), so it appears I already have a +0.40 oversize bore and piston already.
Will upload a pic in a mo, so I think I can say the head and barrel have been off before, the thing has been overbored and larger piston and rings fitted and tehn to add icing to the cake a previous owner got lairy with the black ATV silicone on every mating surface.
So bloody annoyed right now.
It's looking like a piston and barrel set is on the cards but i'm at the point where i'm seriously considering binning the lot as a needs rebuilding / project and looking for a 500 that's had someone with a modicum of mechanical sympathy caring for it in the past.
The thing with that is it'll then have defeated me but if I spend on the bits and get it up and running again i'll be disinclined to sell it having spent time and money and then be wondering what else may have been bodged!
Gaaaaaaaaarrrgghhhh!
Got a set of new piston rings in the post with head and base gaskets etc when I was contemplating re-using the old piston.
Fitted them to the bore to check the end gaps, the end gaps were immense, I could measure them with the external prongs of the vernier calipers!
Thought, this just doesn't seem right, checked diameter of an old ring and the new with the gap closed up, the old ones are bigger.
Dug out the old first head strip pics and had another closer look at the piston crown, (I don't have internal micrometers and the only external I have is a narrow range so measuring said bore and piston accurately is not possible), on the crown under magnified inspection the bit that I thought said T040 looks like +040, (makes more sense), so it appears I already have a +0.40 oversize bore and piston already.
Will upload a pic in a mo, so I think I can say the head and barrel have been off before, the thing has been overbored and larger piston and rings fitted and tehn to add icing to the cake a previous owner got lairy with the black ATV silicone on every mating surface.
So bloody annoyed right now.
It's looking like a piston and barrel set is on the cards but i'm at the point where i'm seriously considering binning the lot as a needs rebuilding / project and looking for a 500 that's had someone with a modicum of mechanical sympathy caring for it in the past.
The thing with that is it'll then have defeated me but if I spend on the bits and get it up and running again i'll be disinclined to sell it having spent time and money and then be wondering what else may have been bodged!