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Ducati cylinders are plated or coated with something, correct ? So... If you bore them out , where do you get them redone and what does it cost ? Is there someone who will bore and plate them , too ? I am replacing my cylinder studs on the front cylinder. I was going to do rings while I was in there but the price seems to be really high ($150). Do you hone these cylinders or how do you prep them ? Is there anywhere to get reasonably priced rings or do I just button it back up and smile about it ?
 

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+1


Cheaper to fit hi-comps whilst you are in there, good power gains too! :)

IMHO I would advise a very light barrel hone with some scotchbrite or very fine wet & dry paper before you rebuild to bed the rings in.
 

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Thanks again. You are my Ducati Encyclopedia !
 

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Is this a 1996? How do you know you need rings? They last a long time. Measure the end gap; they might be fine. A very light hit with a ball-end hone works well too, if you find you need new rings. I broke a ring when I replaced my oil galley plug and went the 11:1 Wiseco piston route. Adds a nice hit.
 

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I don't think I need rings, but if they weren't so damn much, I would replace them while I'm in there. About 28000 mi. On motor, no records from FO.
 

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Local Wrench

Doing the work yourself ? Call the Ducati Shop in Northville? just picked up some belts today.

Q:"A very light hit with a ball-end hone works well too"
 

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$800 for big bore 944 kit !
 

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I take it that's including the bore out and replating ? Yes, I do my own work, except for machine shop stuff. I'm pretty good at breaking them, so I had to learn to fix them. Bikes are like naked women, don't put one near me and expect me not to put my hands on her ! Ducati ought to hire that Abarth girl ...OH MY !
 

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when replacing rings or rebore and coating with new pistons and rings, getting the rings to seat is critical. Breakin under load and use the rpm, preferably breakin on a dyno or the track otherwise you will get gases passing by the rings
 
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Opinion

This is a question that has been conjectured over for many years. There is no quintessential answer, only preferences, especially with nikasil coatings. It goes hand in hand with how to perform a break in.

Personally, after experience with a lot of race and street engine, I can say that the worst mistake to make is to overheat a new set of rings. The second worst mistake it to baby them. My opinion is that the engine should run up to temperature at a high idle and then be cooled down. Rinse and repeat a couple times. Then put it on a dyno or the track and run it hard for a short period. Cool down. Repeat. Change the oil to get the junk out, sticking with mineral based. Next change, convert to synthetic.

It's only an opinion. I have seen vehicles take 40K miles to break in on a mild break-in on synthetic from the start. Even so, they never run as hard as a proper break in because the rings never seal as well as they do with high pressures initially. Every manufacturer would recommend a slow break in because they don't care about performance, only warranty claims. A piston that isn't sealed very well will generally be denied warranty service just because it consumes oil. If its passes DEQ, good luck with a warranty complaint over oil consumption.

Many engines that are broken in at the factory when connected to massive volumes of mineral oil that is highly filtered are delivered with Mobile One. People confuse that to mean that the engines break in fine with a synthetic. Some of the newer Japanese car rings are extremely soft and seal in a different way. A starter motor can break them in. I do not know if this technology has moved to motorcycles and that is another source of confusion and misleading information. They however, will not suffer from an aggressive procedure because they are essentially already broken in after the engine starts idling. They smoke for mere seconds after start up. Honda started this in the late eighties.

Now, you can essentially find many that completely disagree with all this. I just know what has worked for me and my associates and what hasn't. You will make your own choices based upon your results but if I were you, I would flush the synthetic out, put mineral based oil in and head to the dyno or track and hope to remedy the situation without a tear down.
 

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Look at the condition of the cylinders and if they do not have any gouges you can sink a nail in then they should be fine to run. Yes some need to have a glaze breaker hone run through them or they will have blowby but Nikasil is very tough. Be sure to use the proper hone so you do not damage the surface though.

I have torn down plenty of 50,000 mile motors and had pistons,rings and cylinders no different than a 10,000 mile cylinder. Yes you should check everything but the odds are in your favor, more harm can come from trying to remove the rings to check end gap as the oil ring is easily broken. The $800 set of pistons are probably Pistal pistons which are arguably among the best, in some ways you get what you pay for. A set of JE or Wiseco's are good enough for most people but if you held them in your hands you would see why the price difference. I have used most of them and it is a case of buying the right piston for the job.

I am one who would say if the rings or pistons need replacing look at a set of wiseco (ferracci) drop in high comps. If you have cylinders that need plating I would go 944 or 950 as the only added cost is the boring of the cylinders.

Have you checked your crank plug while you have it apart?
 

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Give me a clue as to how to see the crank plug ? Can you see it with the motor still in ? I have an inspection camera but I was just curious as to what I'm looking for, I could not see a thing when my horizontal cylinder was off. Couldn't get my head in there. To follow up on my ring question, I found a great deal on a new piston and rings. My cylinder looked great, I did one easy pass with the hone, wiped it with wd40 , and reassembled, it broke in very quickly and all is well.
 

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Give me a clue as to how to see the crank plug ? Can you see it with the motor still in ? I have an inspection camera but I was just curious as to what I'm looking for, I could not see a thing when my horizontal cylinder was off. Couldn't get my head in there. To follow up on my ring question, I found a great deal on a new piston and rings. My cylinder looked great, I did one easy pass with the hone, wiped it with wd40 , and reassembled, it broke in very quickly and all is well.
After honing the bore yous should wash the cylinder with water and detergent and the re-oil it. This removes the tiny particles left over from the process that could otherwise embed themselves in the aluminium piston.
 

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At 28K, I'd say leave it alone, unless you can see something is not right.
My bike still has the original pistons and bores.
I put in new rings at 122K. My current set now has 138K on them and should be replaced soon.
I had the horizontal cylinder head off recently, and the original piston and bore still look good.

PhilB
 

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Yes you can see the crank plug in the frame if it is out. Look between the left side crank cheek near the pin and the main bearing. The crank plug should be recessed not proud of the crank cheek.

No camera needed just a flashlight. If you see no crank plug in the area mentioned that is a good sign.
 

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According to a friend that does Nikasil plating for a living you should never run a hone in them. The coating is so hard that it cuts the hone material up and that ends up stuck in any of the scratches that were made when the bore was originally sized with a diamond tipped cutter esentualy creating a surface that will wear your pings down quite rapidly.

He recommends that you clean them with Scotchbrite and muriatic acid and then wash them with enough water to neutralize the acid and then dry and oil them. The acid is used to remove and aluminum that has gotten smeared onto the cylinder wall. Wear gloves and eye protection!

Further on to assembly there are some builders recommending a dry cylinder assembly to better seat the rings. I've tried it, but then I chickened out and put a little oil on top of the piston as I was scared of rust forming if I end up leaving the engine sit for some reason. What I won't do any more is lather the cylinder with oil during assembly. There's no point to getting oil behind the compression rings and soaking the sparkplug on the first revolution. I just lightly oil the cylinder with a clean finger and slip in a dry piston.
 

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According to a friend that does Nikasil plating for a living you should never run a hone in them. The coating is so hard that it cuts the hone material up and that ends up stuck in any of the scratches that were made when the bore was originally sized with a diamond tipped cutter esentualy creating a surface that will wear your pings down quite rapidly.

He recommends that you clean them with Scotchbrite and muriatic acid and then wash them with enough water to neutralize the acid and then dry and oil them. The acid is used to remove and aluminum that has gotten smeared onto the cylinder wall. Wear gloves and eye protection!
That sounds a lot more like what I've heard about nikasil plated bores. Basically leave them alone unless you're doing something major like a rebore for a 944 kit.


I replaced the rings at around 25,000 kms because I broke one while reassembling the engine after replacing the cyl studs - but they were fine otherwise. Bike now has about 68,000kms on the clock. No honing done, and just a light oil on assembly.


ARRGGGHHH!!... Just looked at the original post date for the thread. :eek:
 
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