Sachs wont fire

Sachs 505d wont run. Great spark. Seems to have compression. Wont start.

80 athena

Hpi

15mm bing

If the seals are junk would it still fire?

Re: Sachs wont fire

> K Olena Wrote:

> -------------------------------------------------------

> If the seals are junk

If you don't know their condition , it's time to replace them so you do know .

Do a leak down . That will show you where any leaks are .

Re: Sachs wont fire

I found out why my bike wont run.

Piston melted by the ring set pin. Scored and toasted the cylinder.

Oh well. Ordered 80cc Athena Reed kit

1592181940993-115996157.jpg
15921820054991021833555.jpg

Re: Sachs wont fire

Why was the pin and ring ends going directly over a port ?

That should never happen .

Re: Sachs wont fire

Way the kit is.

Re: Sachs wont fire

Would be nice if they make the ring gap slide on a solid surface

Re: Sachs wont fire

No way i'd run something like that .

Either use a different kit or change the pin location on that kit .

Who ever designed that had their head where the sun doesn't shine .

Re: Sachs wont fire

What kits dont do this?

Re: Sachs wont fire

You sure that piston wasn't upside down? I've seen many kits, and the most basic thing from an engineering perspective when making a kit is to make sure the pin is not over a port.

Re: Sachs wont fire

The kit has a port on top and bottom. Im pretty sure i installed the piston correctly.

look at my slop!

Re: Sachs wont fire

i support the piston upside down assumption: i can almost convince myself i see the arrow on the piston head (which should point toward the exhaust) on the opposite side as that smear

Re: Sachs wont fire

There are no arrows in the piston swoop

Re: Sachs wont fire

> K Olena Wrote:

> -------------------------------------------------------

> There are no arrows in the piston swoop

Then put the piston in the cylinder bottom. Line up the cutouts in the cylinder skirt with the cutouts in the piston skirt . They should be an obvious match . That's how the piston should fit on the rod .

Mark the piston so you know which is the exhaust side . Maybe a scratch inside the piston skirt .

Re: Sachs wont fire

Good advice man

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