Piston cleaning of carbon build up

braaap!

New Member
Hi gang!

Restoring a 1981 Honda CB650 and I have heaps of carbon build up on pistons and valves.

What's your best method to clean them up?

Thanks!


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Oven cleaner should work pretty well on the pistons and a nylon brush.

For the valves, you can use a wire wheel on a bench grinder to get them clean.
 
I use gasket remover (aerosol) followed by a plastic scraper. Follow up with scotchbrite pads!
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That was just the gasket remover, didn't take another shot after scotchbrites
 
Be careful of oven cleaner on aluminum. Don't let it sit in the ring grooves. It may ruin the piston.
 
That little bottle of RxP fuel treatment stuff works as well as anything I've ever tried.
 
braaap! said:
Works with both valves and pistons?


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Yes. Just a rag or maybe some very fine, 0000 steel wool. Or a hard bristle nylon brush or a soft brass brush. But I've found that if you let the RxP sit, it'll almost wipe off.
 
can't seem to find it here in Montreal but will try with something similar such as http://www.canadiantire.ca/en/pdp/stp-octane-booster-0380791p.html#srp
 
I can't say if that stuff will work or not. I only have personal experience with the RxP.
 
Be very careful using oven cleaner on aluminum (ie pitons); they react badly together if left alone.
braaap! said:
Thanks a lot! Why not oven cleaner on valves?

It's not that oven cleaner is a bad thing on valves. Valves are steel not soft aluminum, so you can just stick them right in the wire wheel. Chemicals aren't bad, just not needed.
 
I use Würth gasket remover, industrial grade. Basically you want something with lots and lots of solvents in it and pistons and valves come out clean with little to no mechanical work. (Which usually only leads to destroying other parts in the process!)
 
I have the luxury of a reasonably large, heated ultrasonic bath. Before that I used organic solvents and the least amount of mechanical traumor to the parts being cleaned. Always be very wary of going the quick "power tool with a wire wheel" trick as it will often remove material from the part, in all the wrong places, faster than it removes the crud from the part.

Bear in mind that this part is about to go back into a foul environment and isn't perfect in terms of surface then you're best just getting the worst of the cacky off with fairy liquid and a good scrubing brush and refitting it unless you want to spend a long time making it perfect.

Try buying a few pints of diesel and just letting them soak for a week..... you might be surprised.
 
Guys,

I was told to try Pine Soil to remove carbs.

Cheap stuff and, above all, no toxic fumes.

Here are the results! I think it's pretty amazing!

It took about 2hrs per piston to clean them thoroughly.
 

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