Cleaning carbon from piston tops?

[Ratfade]

I have the heads off for porting and clean-up, so I pulled the jugs for a look as well. All looked fine, but I was wondering about a good way to safely clean the carbon build-up from the tops of the pistons.

Thanks.

[ClassicRider2002]

".........I have the heads off for porting and clean-up, so I pulled the jugs for a look as well. All looked fine, but I was wondering about a good way to safely clean the carbon build-up from the tops of the pistons........."

Well I just did this.....you mention above that you "pulled the jugs" so that means perhaps your pistons have been left inside of your cylinder jugs and pulled as a "unit" from your bike? Or are the pistons still connected to your crank arms and the cylinder jugs are removed from the bike....?  Simply picturing what you got going....

Why don't we start there first.....

But I will tell you what I have done.....I pulled my heads off for ccing and clean up as well....getting them back today..... matter of fact.....anyway....

After removing my heads, I went to ace hardware with one of the head bolts, I then had them cut me 4 pieces of pvc pipe @ 1.5" in length which also had an inside diameter that would allow the cylinder head bolt to be pushed through.  I then took the two shorter head bolts from each cylinder and placed each one of them in holes criss crossed from one another, ie: either in holes 1 and 4 or 2 and 3 doesn't matter which pattern as long as criss crossed.  The reason for the length of 1.5" for the pvc piping was because I took a measurement and determined that the length of 1.5" would keep me from bottoming out the head bolt when tightening down and is the depth from the top of the cylinder head and the base of the cylinder at the point where the short head bolt is secured......I used the short head bolts as fasteners because they are shorter and not in the way as much.  I left the old head gasket in place so as to keep from scoring the top of the cylinder jugs....and I tightened each head bolt enough for firmness but I didn't crank it down tremendously hard.  The purpose for doing this is that right after moving your cylinder heads the jugs have a tendency to ride up and down and come off of their seal if you ever rotate a tire or in this case wish to work on the pistons....so this was a way to secure everything from getting bumped as well.....Once the cylinder jug is secured here is what I did...

I took my cordless dremel tool ( a fantastic tool) to own for a motorcycle....cleaning of bolts, cutting small bolts and on and on....anyway I purchased a dremel 3/8" Flapwheel 120 Grit the Dremel part number is # 503.  The flap wheel has little slits all the way around and is of a cloth type material yet rigid enough not to fall apart....and I simply began dremeling the carbon away.....it was so precise in doing it's job....that when I finished I could read the original serial numbers stamped into both pistons....it did not scar the top of the pistons or dig in or gouge anything.  Of course the diameter of the flapwheel itself keeps you from reaching the edge of the piston nor does it allow you to easily remove carbon that has built up in the valve cut outs....so next I took some contact cleaner on some #0000 fine steel wool and began rubbing down the carbon buildup @ the edges of the piston using my thumbs to remove the carbon from the valve cut outs in my piston tops.....I also used a vaccum while using the flapwheel to remove/capture the dust as I was removing the carbon...and  I would use the vaccum while using the steel wool as well.....Once the piston top was at the condition I wanted it I then rotated the rear wheel to the point where the piston  I was working on had dropped down enough to clean the wall of the cylinder jugs with soft micro fiber cloth....also vacumming out anything which slipped down.....All material (which wasn't that much at all) was removed successfully and the cylinder wall will be "greased" like a cake pan with assembly lube or motor oil  prior to reattaching the cylinder head....

I have photos of this....and would be glad to send them to you or to anyone whom wishes to place them on here I simply have no more photo storage here at HTT and I don't wish to join a website photo place yet......

Hopefully this helps you.....

I am quite pleased with the results....the piston tops had enough carbon on them that to have cleaned the cylinder heads and freshened them up and not to have also done the piston tops wouldn't have been right.....there are several technical articles about the idea of doing this stating the merits of such carbon removal.......for me it's like starting fresh again.....

Some might think two negative things about this, what about loose material getting down the cylinder wall some might think about gouging the piston if procedures are done with care both are avoidable.....and simply not a problem.

I suppose my method is for someone that doesn't want to seperate their pistons from their cylinder jugs which would require reringing as well as regaping.....nor going through the process of removing the pin circlip.....thus not disturbing one's piston.....so if one's plan is to do all this....then my procedure is pointless....but it worked for me.....because of what I was after.

Regards,

"Classic"

[still_havinfun]

the last time i did the piston carbon, i set the pistons in a container and poured some Berrymans-B12 to cover the carbon and let it set overnight and it will disolve about all the carbon. anything left can be cleaned off with a tooth brush and you don't damage anything. it's very good in the gas tank also.

[Scramjet]

I have the heads off for porting and clean-up, so I pulled the jugs for a look as well. All looked fine, but I was wondering about a good way to safely clean the carbon build-up from the tops of the pistons.

Thanks.

I left my cylinders on and secured them with head bolts through 3/4 drive socket.  Tighten with fingers only.  Rotate piston to TDC.  Scrapped the carbon off with a metal scraper and finished with WD-40 and scotchbrite.  You must be very careful with the scraper.

Done.  It just took some care and time.  Wipe repeatedly as you go and use a shop vac every couple of minutes for debris.

B

[Tre_11 FLHX]

   Berrymans B12, what I use! 

[Ratfade]

Lot's of good info here. The cylinders are off the pistons, but the pistons are still attached to the connecting rods. I wasn't planning on replacing the rings. Should I?

[Scramjet]

Lot's of good info here. The cylinders are off the pistons, but the pistons are still attached to the connecting rods. I wasn't planning on replacing the rings. Should I?

Be very carefull with the cylinders off.  I would not do it unless the cylinders were on or the pistons were removed from the rods.

Too much risk.

B

[Ratfade]

Scram,
The risk you're talking about is the risk of dropping carbon or other crude down into the crankcase, right?
What about replacing the rings? The engine doesn't use any oil?

Thanks.

[02FYRFTR]

Take cylinders to local indy that can cloth hone them lightly and use new rings also be sure to replace the wrist pin circlips.  Remove only one clip from each piston and you will only need two new circlips. JMHO

[ederdelyi]

>>The risk you're talking about is the risk of dropping carbon or other crude down into the crankcase, right?<<

There's that, but the risk of piston damage from making contact with studs, etc. while trying to scrape off the carbon is high. And not just scratches or scoring can happen ... it's pretty easy to collapse the skirt of a piston enough to cause problems down the road when the piston is not in it's cylinder. Debris control is "easy" to deal with, physical damage is not.

Depends on one's philosophy, I suppose, but my "rules" state that no machining, grinding, or similar operations take place in the assembly area. JMHO, YMMV

[Don D]

ED
Does that include grinding the pinion case boss? That is an operation that makes me cringe every time I do it despite using a whole roll of blue tape almost.

[Admiral Akbar]

Knowing Ed, he probably disassembles the motor for that...  Max

[ederdelyi]

>>Does that include grinding the pinion case boss? That is an operation that makes me cringe every time I do it despite using a whole roll of blue tape almost.<<

That's one of those situations that require "special considerations" :>) When I have to do operations like that on an assembled or partailly assembled engine I do everything possible to contain/remove debris and the operation does not take place in the assy. area. My rule is to treat the assy. area as a "clean room" which includes the use of finger cots and gloves when handling components.

It's the "details" thing. Overkill? Can't help it, it's the way I do things.

[Don D]

Not overkill, I ask to learn, Thanks

[ederdelyi]

>>Knowing Ed, he probably disassembles the motor for that...  <<

Sometimes :>) If I can find a reason to justify it. Anality (is that a word?) is a "sickness" that I haven't found a cure for, not sure I really want to.

[Scramjet]

Scram,
The risk you're talking about is the risk of dropping carbon or other crude down into the crankcase, right?
What about replacing the rings? The engine doesn't use any oil?

Thanks.

Moderate to low miles and no oil burning.  I would just slide the pistons back in the jugs and then clean the pistons domes.

Yes debris and physical contact damage.

B

[02GhostRiderVA]

the last time i did the piston carbon, i set the pistons in a container and poured some Berrymans-B12 to cover the carbon and let it set overnight and it will disolve about all the carbon. anything left can be cleaned off with a tooth brush and you don't damage anything. it's very good in the gas tank also.

I performed the same procedure with Marvel Mystery Oil instead of B12, with the same results.

[V24me]

I just did this (I had the cylinders cross hatched and new rings).  With pistons still connected, I covered the gap into the lower end with towels with holes for studs and piston.  Also made sure to wrap cylinder studs with shop towels (no contact with piston!)  Then I took a piece of plastic and fit it over the studs and piston (with holes) and used masking tape to seal up the lower end.

Then I used a wire wheel (air powered) and gently cleaned the top of the cylinder.  Then vacuum to clean debri and carefully removed plastic.  Did heat cycles to condition the rings and changed oil right away.

[tipper10]

YOU WON'T SEE THE RESULTS, BUT ITS BEEN USED FOR YEARS, WORKS ESPECIALLY WELL ON AIR COOLED ENGINES, GOOD OLD H20 (WATER) FROM A SPRAY BOTTLE INTO CARB OE FUEL INJECTION REV UP TO ABOUT 1800 RPMS. BEEN DOING IT ON MY 2000 FXDWG SINCE IT WAS NEW... I DO IT ABOUT TWICE A YEAR......

[fxstdavew]

Try http://orisonmarketing.com/cleaners/piston/carbon.html   I've never used it but looks interesting

[Deye76]

  Berrymans B12, what I use! 

Where can this stuff be found? Auto parts?

[Rusty Steel]

  Berrymans B12, what I use! 

Where can this stuff be found? Auto parts?

Yes, Autozone, O'Reilly, Pepboy's autoparts ect...

[DaleW]

I cut off the end of one of my dremel tools,put a slot in the shaft  then wrap emery tape around it.The tape does a good job of grinding down lots of things.