Ducati Monster Forum

What is your opinion on honing cylinder walls? I am installing new piston rings on my M696 pistons and the cylinder walls do already have original cross-hatching- should I still hone the cylinder walls before installing the pistons with new piston rings?

What is your opinion on honing cylinder walls? I am installing new piston rings on my M696 pistons and the cylinder walls do already have original cross-hatching- should I still hone the cylinder walls before installing the pistons with new piston rings?

Yes, it needs fresh hatching for the new rings to seat properly.

Cylinders should be honed when re-ringing to remove any glaze that is present. A ball hone is the proper tool.

I've done both with and without honing. Still no idea with which results. Difference? Don't know. Same/similar durability.

I thought I posted, but it's not here.

I suggest honing with a ball hone to remove any glaze.

Thank you, everyone. I'll use a ball hone as suggested.

Emphasis on "any glaze".  And make sure you clean the cylinders very well.  You do not want to hurt the nikasil coating.  White cloth until you see no gray. 

For the last three or four decades there has been two camps, hone band don't hone.  Big reason for the two camps is engine failure from grit.

The Nikasil coating is just that, a coating. Don't go honing it enthusiastically like old school steel cylinder sleeves or cast iron barrels. Be careful to get hold of the appropriate tool for the job, so see your local hot rod shop for advice. Sometimes a pan scrubbing pad (not steel) and parts cleaner can be enough. The appropriate honing tool will be on the gentle end of the spectrum and there must be new tools out nowadays. The honing tool I used on my old T140 and Shovelhead will be pretty brutal on Nikasil.

Thanks, guys, and now I'm having second thoughts haha... what do you recommend using to clean the bores?

Koko is right about it being a coating, but...I know that used cylinders, when being recoated, the thickness can be adjusted to properly clearance the pistons.

That said, if you're scared, use a red scotchbrite pad with some kerosene, or diesel fuel, and lightly scour the bores. That will not remove the coating..

Got it. What do you think about this- https://www.harborfreight.com/4-in-180-grit-abrasive-ball-61184.html?utm_source=google&utm_medium=cpc&utm_campaign=19231709222&campaignid=19231709222&utm_content=141253582541&adsetid=141253582541&product=61184&store=577&gad_source=1&gclid=Cj0KCQjwncWvBhD_ARIsAEb2HW9tt4eSfeFAlqxkA8B70X7OoNrHStEdnS4GTd9UBWcu6zKiVgyPyL0aAnsxEALw_wcB

I was thinking by hand but as long as you use your head, and don't overdo it, you should be OK.

Maybe two, or three, strokes in each cylinder? All you want to do is remove any glaze.

BTW...I merged your topics. It will be easier for people to follow along with what happened.

OK, thanks, that's easier and gives me more control over what I'm doing. Before I go at it though, I think I'll take both cylinders to Ducati and see what they think as well. What do you recommend to remove carbon from the piston and top of the cylinder- ATF/gasoline/degreaser?

Hard work with carburetor cleaner or https://orisonmarketing.com/products/piston-kleen%E2%84%A2

To the OP...You might contact the company to see if this product would work t0 safely remove the gaze from cylinder walls.

I think it´s worth here to note some properties specific to Nicasil-type coatings. Nicasil is a Mahle trademark, so technically Ducati cylinders are not "Nicasil" cylinders, but I suppose the coatings are similiar. I still have some old documentation from my time at Mahle in Stuttgart, but I never worked specifically with Nicasil coatings and unfortunately it´s so long ago (30+ years) that I don´t know anyone to ask.

Anyway, Nicasil-type coatings are meant to be extremely smooth, one Mahle document I have says that the honed surface roughness should be Ra < 0.3, requiring an exact diamond hone process.

These numbers alone may not say too much, but for comparison a swedish supplier of brush-type hones states on their homepage that their finest grit brushes gives a surface roughness of Ra3 -  Ra10.

There´s probably more to this, as surface roughness measurements are tricky to understand, and I´m no expert, but the numbers should at least say something.  

Anyway, in my opinion the "glazed" areas often seen in a Nicasil cylinder are not really glazed, they are merely polished and can be used provided there are no damages. Like Lars (mentioned earlier in the thread) earlier, I´ve also done both honed (by a pro machine shop) and "glazed", also with new and old rings, and Like Lars I´ve not noticed any difference to blow-by, oil consumption, etc.

Acc to Mahle spec, the coating is most probably 0.04 to 0.6 mm thick, but can be up to 0.10 mm, so a hone using the proper process is probably OK, but most likely not necessary.

Lots of ifs and buts, since we do not know exactly what Ducati is using, but at least some basic that might be of interest.
    
 
        

Hi guys,

So I took the cylinders to Ducati and they suggested that I just clean them up with gasoline and warm water. No need to do anything else. I'll clean the pistons with gasoline as well using a cloth or toothbrush but nothing harsh.

Let me know you guys think and thank you all for your help!

Nikasil is very hard, and you'll have a lot of trouble honing through it.  To hone it you need a diamond hone as MonsterHPD says, so you would need to find a machine shop that has experience with them to have that done.

To clean it using a ball hone is fine.  All you'll do is scratch the surface a little and take the shine off.