Decarbing pistons not installed

[Reggie08]

Just broke down my powerhead to replace one, maybe two pistons and to swap out the bare block. While I have it all apart, I'd like to clean up the pistons that I'll be putting back in. Is there anyway to de-carb the pistons when they're not installed?

85 'Rude 90hp by the way.

 

[5150abf]

Re: Decarbing pistons not installed

A stiff bristle brush and Sea Foam or deep creep.
Put it on and let it sit for a bit and scrub away, works really well.

 

[Reggie08]

Re: Decarbing pistons not installed

I'll give it a shot. How 'bout using a wire brush on a cordless drill? Will that be ok?

 

[CBINMN]

Re: Decarbing pistons not installed

No expert here but I believe that would leave tiny pieces of wire embedded in piston. I just finished a rebuild and I used the method mentioned above and it worked well.

Chris

 

[samo_ott]

Re: Decarbing pistons not installed

I use the wire wheel on my grinder. Works great and fast. Maybe not the best way though.

 

[Silvertip]

Re: Decarbing pistons not installed

You should use a ring groove cleaner tool to clean the ring grooves. I would not use a wire wheel on the sides of the piston. You can generally scrape the carbon from the piston crown and clean it up with a brass bristle brush.

 

[Dhadley]

Re: Decarbing pistons not installed

Before you spend a lot of time cleaning old used (worn) pistons, have the cylinders measured. If they need boring then cleaning the old pistons is a moot point.

 

[Reggie08]

Re: Decarbing pistons not installed

Before you spend a lot of time cleaning old used (worn) pistons, have the cylinders measured. If they need boring then cleaning the old pistons is a moot point.

I'm buying a bare block that'll be bored .030 over. Should I wait till I get that first to make sure the pistons fit? The current pistons are stamped "030" on the ends which my pea-sized brain says they're .030 pistons.

 

[Dhadley]

Re: Decarbing pistons not installed

Is it a fresh bore or a block that's been bored and run?

 

[Reggie08]

Re: Decarbing pistons not installed

Should be a fresh bore. Faztbullet is boring it. My current block appears to have been re-sleeved. The previous owner said it was re-sleeved as well.

 

[CharlieB]

Re: Decarbing pistons not installed

If you understand how the hone marks on a fresh cyl wall hold oil to lube the piston and rings during the break-in then you should also understand how the small grooves on the piston skirt also hold for lubrication.

DO NOT BUFF EITHER the piston skirt NOR the ring lands with any wire wheel. The aluminum piston is much softer than even a brass wheel and will smooth those surfaces, loosing their oil holding ability.

Carb soak works well to desolve carbon deposits in ring lands and washes out easily with a solvent brush.

 

[samo_ott]

Re: Decarbing pistons not installed

What about the top of the piston itself?