Pistons

Hi,

On the last track day my bike started to make strange noises so I decided to call it a day and have a look at the engine at home. Once the engine was opened it became clear that a new crankshaft with all bearings and boath rods are needed to be replaced. The pistonas have some scratches only on the part that is visible in the picture below. What do you think? Are they done as well? The bike is being use only on track.

By the way, happened on the first lap in the season


Thanks, Andrej

I would certainly do all bearings and rings and have a machine shop check the pistons and sleeves.

If you have scored pistons then likely will have damaged the liners. At that point you either have machine work and new pistons or find another assembly.

Take it one step at a time and have it inspected first.

Seth Vo said:

I would certainly do all bearings and rings and have a machine shop check the pistons and sleeves.

If you have scored pistons then likely will have damaged the liners. At that point you either have machine work and new pistons or find another assembly.

Take it one step at a time and have it inspected first.

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Agreed

Any score marks on the cylinders? Can you feel the scratches?

What we’re your maintenance intervals and how many miles on the bike?

damn just ripped it apart at home eh? i wish i had the setup to do that type of thing! can you share more pics of the tear down?

@AlfaFox Andrej let us know of how bad this is or what happened?

I assume since you've shown the piston and sleeve you are able to do the full rebuild on these. Please confirm and happy to help with any questions.

Seth Vo said:

@AlfaFox Andrej let us know of how bad this is or what happened?

I assume since you've shown the piston and sleeve you are able to do the full rebuild on these. Please confirm and happy to help with any questions.

Click to expand...

So a little more about what happened.



Bike has 22k km and was bought with a little less than 20k km. I did 2k km on track. Previous owner had it converted to a track bike but I couldn't get any info about how many track km the bike had.

All the time it was running just perfect.

During the winter I did a ''desmo'' service (with help of a friend/mechanic who also races a V4r), suspension service and basically checked almost every single screw od the bike. All was good with valves clearances as they should be. At the beginning of March I attended a track day and at the end of the first lap when I closed the throttle the bike started to slow down like I was breaking although I didn't touch the brakes. At that point I pulled the clutch and the rear wheel just blocked and the engine shut down. I was riding at around 140km/h at that time and with the rear wheel blocked and sliding I went straight in to the gras but somehow managed to stay on the bike and stop before the barrier. Once I stopped put in neutral and the rear wheel was now moving fine. I started the bike up with no problem and the only thing strange was a little of strange noise coming from the engine at 3000 or 4000 rpm and above so I went back to the pits really slowly. Of corse I didn't ride the bike that day any more. My friend was also at that track day so we decided that he will take the bike to his place and we will take a look there as he has all the tools needed. Once the engine was opened we saw that the crankshaft, rods, rod bearings and pistons were damaged. Piston sleeves looks ok but the pistones are scratched on the sides where they are black.



I decided that I will replace the damaged parts with new. Doing so I will basically have a new engine which should be god for quite some time.

Those bearings look to be in pretty poor shape for only 12k mi. I wouldn’t be surprised if all those miles were on track and the oil not changed frequently enough. Yikes. How did the head look when you were in there? Any score marks on the cam?

But as long as crank is good it should be salvageable with new bearings and pistons and sleeves you should be good.

That's really unfortunate and sorry to hear. Really hard to say if there was anything going on before since you only put 2k on it since you bought it.

Good thing you have a friend with the knowledge and tools. I had a similar but different experience with my 1199 where I bought it and found out later the casing had a crack and now I'm rebuilding mine also. See my build thread in the 1199 forum, rebuild thread.

Only good thing is I get to have the wonderful experience of building these beautiful motors...

Yes the piston is garbage now. All the material from the bearings gets thrown up on the pistons like that and ruins the skirts any time you tun an engine after bearing failure.
Done it myself. Your cylinder walls will also need to be cleaned up.

outhouse said:

Yes the piston is garbage now. All the material from the bearings gets thrown up on the pistons like that and ruins the skirts any time you tun an engine after bearing failure.
Done it myself. Your cylinder walls will also need to be cleaned up.

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Yes, that's exactly what happened. Fortunately the cylinders look good but will be cleaned/polished anyway (sorry but I don't know the right english word for this kind of process).

So far I got a new crankshaft, rods and rod bearings. Still searching for pistons (new) and crankshaft bearings. Need to get the bike back together in 3 weeks for next track day

Unfortunately I didn't make any pictures during the tear down but I have the end result....not a pretty sight...

Sounds like good progress. Make sure to match the cylinders to the pistons (A- A, B - B). Also you should have a machinist determine what is required to "clean-up" or hone the liners as you need to make sure the piston to cylinder clearance is to spec.

Seth Vo said:

Sounds like good progress. Make sure to match the cylinders to the pistons (A- A, B - B). Also you should have a machinist determine what is required to "clean-up" or hone the liners as you need to make sure the piston to cylinder clearance is to spec.

Click to expand...

Thanks for the info. Yes that's the process. The cylinders will be honned and the pistons with the bigger diameter will go in, just need to find them for a better price than at the official ducati dealer.

There are a few aftermarket that build to Ducati specs, I'll see if I can find them for you

Seth Vo said:

There are a few aftermarket that build to Ducati specs, I'll see if I can find them for you

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This is one that keeps coming up based in Italy that supplies many OEM's. Check them out Vertex Pistons, Inc.

Love your special stand! What ever does the job, right…

One more note it I believe the liners cannot be bored due to silicon carbide coating so be careful or ask you machinist or the piston manufacturer for options. If you find a 1st over bore then there must be options but I have not explored this yet and normally stick with the matched piston and liner sets to maintain the .065 to .085mm piston to bore clearance