Cleaning carbon deposits Off Pistons

[Falco]

With the head off I noticed the piston heads (crowns?) were a bit mucky.
Is this a normal level of carbon build up for 30K miles?

How do I clean it off? It seemed pretty set, would a brass wire brush fitting on a drill destroy the piston head underneath?

Presumably, however it gets cleaned the engine will have to be turned over to put the piston head level with the top of the block to avoid getting bits into the bottom end?


https://preview.ibb.co/gei5o6/IMG_20171028_194555225.jpg
https://preview.ibb.co/jkHWT6/IMG_20171028_194609850.jpg
image hosting service free
____________________
I tell you what, mathematically, I'm having it

[Pete.]

Tooth brush and petrol/brake cleaner will shift the most of it. No harm done to leave it there though.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Falco]

[Teflon-Mike]

Oven Cleaner is one of the best de-carburisers known to woman-kind.... Basically, Caustic Soda.... you can still buy bags of the stuff in crystals from the super-market to mix in a bucket of hot water and soak stuff like crappy baby-grows in, that's exactly the same as they used to sell in 1l bottles with a brand name and the title "Two-Stroke Exhaust Treatment" on it, to do the same thing, for five times the price!

Oven cleaner foam, though is a bit more convenient; spray soak, scrub with a tooth-brush, rince.
It will get past the piston rings though, so plan new on oil rebuild and a short change after bed-in, like 150-200 miles on, to flush contamination...

Another tip there is to add a squib of washing up liquid to the oil just before, or even during, warming the engine before dumping the old oil.

Also worth wiping the bores with some LM grease (or a quick squib of chain lube) when you crank round to do the next two slugs, and on those slugs walls when you have done them, so that there is some decent lube on the walls come first crank and start... remember the bore is 'honed to put a slightly rough finish on it that breaks the surface tension of the oil and keeps it in the dimples. A good de-coke will take out not just the carbon deposits where there's no metal on metal rubbing, but also all the oil on the walls, and they will get rubbed before oil pressure gets up and gets them properly coated again..... This tip holds whatever solvent/redox agent/deturgent you use, BTW.
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[stinkwheel]

That's a comparatively small amount of carbon build-up.

Check out this one. (Collapsed piston crown pinching the oil control ring).

https://www.bikechatforums.com/download.php?id=100490
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[MCN]

Caustic Soda oven cleaner will dissolve carbon and also very effective at digesting aluminimininmin. So be warned.
____________________
Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[Falco]

In the end a toothbrush and brake cleaner made a decent job of it. Next time I am that far into the engine I'll be sure to bring back a bit of NaOH from the lab before hand.
____________________
I tell you what, mathematically, I'm having it

[sickpup]

[RhynoCZ]

The best way to keep your engine clean is to use it properly. Rev it up to the top every now and then. I do this with every vehicle I have/had and the combustion chambers are so clean you could eat out of them, if you don't mind the cancer.
____________________
'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[ZRX61]

[stevo as b4]

I'd have said on an assembled running engine that carefully spraying in water to the intake for a few minutes at a very fast idle would clean out as much carbon as you could by scraping.

If doing the above, I'd be careful and cautious and do it right before an oil and filter change.

On a disassembled motor, I'd try an acidic alloy wheel cleaner or vinegar instead of anything caustic. Alloy wheel cleaner can't be anything too aggressive generally as its not supposed to damage paint just lift off the dirt and baked on dust.