New victim in Phoenix AZ (continued from the INTRO section)

[ducadini]

Like the modern(ish) bikes, love the bevel.

Blew the top end ? As in : it exploded, imploded, or just quit giving bangs ?
Seems like a 860 engine, so one plausible cause is the ignition giving up under 2k rpm (or giving up completely).

No rocketsurgery, just brainscience as long as you follow some simple rules the patient WILL ride again

If dismantled : check the rear head for 'the' crack between exhaust valve and port.
Happens mostly on the 860 and Darmah, probably (empyrically checked) due to overheating of the rear head.
Since Your bike isn't really standard anymore, I would consider getting rid of the sidepanels (they creat a very nice hot-air-cushion )

Have fun
ciao
ducadini

[HondaFreeSince'93]

Goede midday Antwerpen, ik woonde, kort, in Elsendorp dan in Eindhoven, Maar nu ben ik in orde
Im originally Irish so spent much time over in that part of the EU. Nearly got married in Germany but thankfully I sobered up and came to my senses.

So, this bevel has a history of top end problems, the for sale ad is still on this site with a description from the owner of having had its second top end that apparently didn't take so he was selling it as a bike that he was just "Done" with and had been sitting for 4 years or so: http://www.bevelheaven.com/bikes4sale/M ... /index.htm

When the seller I bought it from got it he put another $2500 into a top end rebuild from a guy in Portland.
So I got it last year, rode it, ran fine and then I moved to Flagstaff which is at an elevation of 2133 meters so the bike seemed to be having an issue with that. I also noticed the front cylinder plug would load up with oil and smoke out the pipe. Only the front. Back was fine.
So I got a so called "Ducati expert" to tune the 40mm DelOrto's since he had an exhaust gas analyzer machine. I figured let me get it done right rather than me guessing as I could never seem to get rid of the front cylinder smoking out the back no matter which way I turned the screws.
He tuned it, it still smoked out the back and 60 Km down the road as I rode it hamo it just dies. No clunky "box of rocks" noises to indicate something was up. No rattles, bangs or thuds. Just quietly stopped as if the ignition was turned off. Lights and electric were functioning, just no ignition.
I pulled off to the side, got off, went to kick it and had no compression. Zero. You could kick it over with 1 finger.
So got it home on a trailer and started my checks. Plugs looked fine, no indication of an overly lean condition that might have burned a hole in the pistons.
I got a bore scope and in the photos you can see the scores on the cylinder walls. I spoke with the "expert tuner" thinking there may be a connection with him having just tuned it and it taking a dog doodie 60k down the road. His opinion was the piston was too hot, liner too cold (it was chilly out the night I rode it back and I was going fast) and bike wasn't warmed up enough. Maybe. Anyway, thats when I decided to never leave it to anyone again and be at their mercy so here I am tackling a rebuild myself.
Ironically, I left the bike to him to do the carbs as I had decided to start riding it a lot more, put up some 1 week trips on it and do some long distance traveling on it.

[ducadini]

Sobered up, came to Your senses and buy a Ducati Bevel
Something's not right

Not really sure what happened on the way home : You say it just coasted to a halt, with electrics but NO ignition.
Then when kicking it over, no compression. On one or both pots ?
Are those High-compression 87mm Asso pistons ?
Am I correct in assuming the damage is done on the righthand side of the cylinder (judging by the cut-outs in the piston).
Since You say it has a history of top-end-problems, were they all the same ?
Seems a strange place to deposit aluminium that high.
And ALL of my piston-cylinder fusions were LOUDLY anounced.
Before we bore You with all the wrongs that could've gone wrong, I suggest You take the engine out.
And check the manual for engine-dismantling preps.
Don't panic, You've got the forum backing You up

ciao
ducadini

[HondaFreeSince'93]

Sobered up, came to Your senses and buy a Ducati Bevel
Something's not right
Yea, good point. I retract my previous statement and will leave it at "I sobered up". To a degree.

Not really sure what happened on the way home : You say it just coasted to a halt, with electrics but NO ignition.
Yes, coasted. Noiselessly. No pops, rattles or bangs. Just died as in loss of power. Rolling on the throttle did nothing. Lights stayed on as it was dark out at the time. Had spark also as I checked.

Then when kicking it over, no compression. On one or both pots ?
Not sure. Will do a test now that you mention it before I tear down. But am guessing both since i could turn it over by hand without any resistance.

Are those High-compression 87mm Asso pistons ?
87 Weisco Kit.

Am I correct in assuming the damage is done on the righthand side of the cylinder (judging by the cut-outs in the piston).
Not sure. I didn't pay attention to which side when I took the scope pics. I'll find out when I pull the heads off.

Since You say it has a history of top-end-problems, were they all the same ?
Not sure. I emailed the original owner but never heard back. The seller I bought it from said it was bored to a 900 as it has 40mm Del Orto carbs on it but then he said something about going back to the original 860 pistons. Not quite sure but I'll speak to him more about it.

Engine out is next, yes. Timing marks seem to be the #1 thing to make sure to line up and mark before heads come off as far as I can gather, but I'll delve into the manual and get a plan going.

Don't panic, You've got the forum backing You up
What could possibly go wrong?.

[wdietz186]

That much metal transfer in that part of the bore is very unusual. I'd suspect an out of round bore or bound up piston rings. The ring lands are the only real mass in that part of the piston. If it was a heat related seizure I would think the piston crown would be scorched/burnt. Stuck/ damaged rings or an oval bore would explain the smoking/plug fouling. I would start by measuring to see if the bore is round. The total loss of compression is perplexing, you should have resistance when the vert. cyl. comes up on compression. A teardown is in order. These engines have lots of parts but there is nothing mystical about them, they are just an engine and you have a loving and supportive forum here if you get in over your head.

[HondaFreeSince'93]

If it was a heat related seizure I would think the piston crown would be scorched/burnt.
Me too, but doesn't look like there was a heat issue on the plugs or pistons.

The total loss of compression is perplexing, you should have resistance when the vert. cyl. comes up on compression.
I have minimal (5lbs or so) resistance from both vert. and horz. cyl, Put my finger over the spark plug hole as I kicked it over and I could fhart with more pressure.
The whole thing is perplexing honestly. Tom, the guy who tuned the DelOrtos, knows his way round Ducati's, he's built and raced back in the day so even he said when he handed it over to me after twiddling with the mixture that the bike sounds solid. I mentioned that I was going to put up a few 400 mile days on it over to San Diego and back for the hell of it and did it need anything else. Nope, just ride it he said.
But the front pot was noticeably smoking out the exhaust a few months prior to that so something wasn't quite right. Or tight.
I'm thinking you may be on track with a ring or out of round issue.

I'll be dropping the engine this coming week, I just got to get all my ducs lined up in a row as to the correct way/procedure to do a top end teardown with timing marks etc. It'll be a fun project really ( I think) and a good way to get up close and personal with a bike I intend to ride the wee wee out of.

you have a loving and supportive forum here if you get in over your head.
What could possibly go wrong then?.

[wdietz186]

Thinking about your symptoms and you saying the heads were redone makes me wonder if you have valves sticking in the guides. If too tight on the exhaust guides it can seize and hold the valve open causing no compression. Depending on the speed and where the valve stuck in its range of travel it may not have kissed the piston or tangled with the other valve. You could try checking the valve clearance at tdc. Normal lash is about.004"-.006" if it is a lot wider it may be stuck or bent. Air cooled dinosaurs require more clearance in the guide than the more modern stuff from the orient. Tom isn't from Mesa is he?

[abmartin]

It's not too difficult to put new liners in the cylinders if you can still get them. I did it years ago on an 860GT with minimal tools and mechanical experience. That bike had experienced major problems with the rear pot.

Are the valves opening and closing when they're supposed to. Do the cam timing marks line up? On a friends bike with aftermarket camshafts years ago the valve timing was one tooth out with the dots lined up.

Original 860GT valve guides were notoriously prone to excessive wear. I've seen them worn such that the holes were about 50 percent bigger than the valve stems.

Bruce

[HondaFreeSince'93]

Are the valves opening and closing when they're supposed to
Yes, it would appear so.

Do the cam timing marks line up?
When both front and rear gear timing marks are lined up rear pot is at TDC, front pot is on the downstroke?

Original 860GT valve guides were notoriously prone to excessive wear. I've seen them worn such that the holes were about 50 percent bigger than the valve stems.
Im ready to pull the motor tonight and wrestle it on to the engine stand, then go about removing the top. I'll check valve guides but as this motor has just had (less then 500 miles ago) a new top end (the 4th one) I highly doubt that they are loose. I stuck a finger in the ports to see if there was any wiggle but so far they're tight.

Murph

[HondaFreeSince'93]

So I got a wild streak tonight and pulled the motor and top end.
The cause of loss of compression is obvious, I'd just like to figure out why it happened.
To my untrained eye it looks like a lubrication issue, or rather lack of?. Maybe I was low on oil?.
I'm not 100% sure what would cause that degree of piston melt. Maybe my carb tuner was right, piston too hot and liner too cold?.
It was a colder-ish evening and I was running hard, but it had already warmed up for 5 or 10 mins at lower speeds. At least I thought it had.

Chime in anytime with suggestions.

[ducadini]

Someone has been working on the heads/camshafts : that nut is NOT stock, nor have I seen anything like it.

Is the damage of the same kind on both pistons ? Or just the rear ?

The only time I saw THAT marks on a piston is when the bigend said enough and pushed the piston against the backside of the cylinder, for the tiny amount of time it takes to pull in the clutch (at 9000).
Are both rods still free moving ?
The ignition of the 860 is a stepped one : it moves from -8 to -32 at about 2000 rpm, so knocking and overheating (due to higher compression) could occur. Is it still correctly timed ?

seems You're in for a liner transplant.

ciao
ducadini

[HondaFreeSince'93]

Someone has been working on the heads/camshafts : that nut is NOT stock, nor have I seen anything like it.
Correct, thats the electronic ignition nut that is on the rear cylinder. That nut takes the pentagon shaped shaft.

Is the damage of the same kind on both pistons ? Or just the rear ?
Yes, same on both.

Are both rods still free moving ?
Yes, bottom end seems fine. I did a brief visual down in the the crankcase and theres nothing I can see to indicate anything off.

Is it still correctly timed ?
Yes, I believe so. I lined up the timing marks on both bevels, they line up every 4 revolutions of the bevels.
When lined up both valves in the rear pot are closed (TDC?) and piston is at the very top.
The front cylinder inlet valve is open and piston is down.

From the little research i have done so far it would appear that overheating due to oil starvation would appear to be what may have caused the seizure. I'm just wondering where all the bits of piston that came off went?. Out the exhaust valves?.Can't go down.

Anyway, called LA Sleeve in .......wait for it......Los Angeles (whoa thunk) and they said they can re-bore my sleeves 20 over which will match the Carillo 20 over thats in the BevHev store. So far so good.
Now to get the wrist pins out as they don't want to come out, guess they like it in that little hole there.
Eviction notices are in order.

[abmartin]

That's a pretty serious seizure. It seems odd to me that both pistons would have the same damage on the sides but as far as I can tell no sign of overheating on the crowns. What do the spark plugs look like? Is the oil level correct in the crankcase? Is the crankcase filter correctly located in it's hole on the inner crankcase wall? Grasping at straws here.

Bruce

[ducadini]

As Bruce noticed, strange that the damage seems to be on the same side on both pistons.
Assume that the bigends are having trouble, then the pistons would both be pushed against the backside of the cylinder, thus creating more heat and running dry over ALL the height of the piston.
I would think that when running a not really warm engine, the pistons would heat up rapidly, and the damage would be high up the crown.
That's why I asked about the rods moving free, or the crank being shimmed correctly so that it can't move side-to-side, then the rods would have problems lining up and the bigends could be gripping for a tiny amount, thus creating trust on the pistons.
Crank is running backwards so that would crate a problem on the rear side of the cylinder.

I must admit I don't have any experience with the full-round pistons, only with the hi-comp Asso slippers (where I found similar damage after the crank went awol).

ciao
ducadini

[HondaFreeSince'93]

In reply to Bruce & Ducadini.
Big end has too much lateral movement so I can safely deduce that this stemmed from my lack of attention to the oil level.
Since I never really rode it much I almost forgot to check oil. That, coupled with a leak somewhere along the barrel line which I never gave enough import to probably reduced the sump capacity to not enough. Big end started to wear from lack of lube and here I am now. I think.
Either way its case split time, not what I wanted to get into but by the time I button it all back together I'll know it will be done right from top to bottom. While I have to go this far may as well build it stronger and better. Or at least find a good machine shop that knows square case Ducs.
GP in San Diego was mentioned to me, any thoughts from the board here on this?.

Cheers all,
Murph.