Not the best of nights

Dellortoman said:
Laverda enthusiasts go on about how unreliable Ducatis are, but I can't recall ever having seen a Duc with a rod hanging out of a gaping maw like a dog's tongue.
Seems to be a regular failure mode for Laverdas.
There are two Laverdas in my workshop now with more than 100,000 km on original rods. I'm wondering whether I should be replacing them (the rods, not the Laverdas)

Cheers,
Cam
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I guess there will be a variety of opinions on that, perhaps also on the reasons behind the failures.  What contributes towards this happening, how often is it the middle cylinder, what could I or a previous owner have done to make this happen, or stop it from happening.  Things that I had noticed in the days leading up to last night included sticking float causing fuel to overflow when engine not running (was advised that this might happen in transit from Canada to Australia) - I removed bowls, pushed floats up to check that they were switching off - all seemed to be OK after that), two incidents of small backfiring and raised idling, hissing from fuel tank cap.  I checked inlet and exhaust fasteners and could not fault.  I removed black fuel tank neck infill to see if this might be the cause, but it was not a constant issue over the week that Ihad it running.

Cost of changing rods vs the vaguaries of the repair bill from this sort of incident might make it a no brainer for many (or some).

I don't feel qualified to offer any opinion on this, only to report what I remember of it, and leave it to those in the know to see what can be learnt from it for all owners.  4500rpm seems to be a popular point for this to occur from a few comments made - should that be seen as having any significance?

Yogi
 
Commisarations Yogi, what bad luck. I will bear in mind the conrod advice given here when I finally look inside my SFC. Wasn't looking at the rev counter when the noises started eminating from my motor but I guess i was pottering along between 50-60 in 4th or 5th. Fortunately no holes in the crankcase.

Seems like you are going to Red for assistance. I enquired about the 1200 casings in LVV in the dition before the current one, they had already been sold so I guess it should have not been included. Might check it out again though.

Scrumpy
 
Thanks Scrumps..

I would be interested to hear from those in the know more about our triple engine characteristics, particularly in regard to rev ranges and if there are certain areas (?4500 rpm for example) that we are best to avoid hanging around for any time when that corresponds to a speed we are looking to hold.  I was there because of the speed limit I was aiming at just being over, but perhaps it might have been better to have knocked it down another gear and run at higher revs?  

Yogi
 
4500 is peak toque point or bloody close.I have sat there and above for hours on the road.Maybe we need a better approach to analysing this statistical.What year model,crank configuration,how many ks done,what cylinder, what capacity,what end of rod,cruising going hard up or down the box,even where in the case it escaped might give a clue.Any evidence of a previous  failure,different texture or colour in the failed section.I find it odd that cruising along at minimal load and bang.Be good to get definitive numbers on this.I defiantly need something to think about just before nodding off to sleep at night.
 
Vince said:
4500 is peak toque point or bloody close.I have sat there and above for hours on the road.Maybe we need a better approach to analysing this statistical.What year model,crank configuration,how many ks done,what cylinder, what capacity,what end of rod,cruising going hard up or down the box,even where in the case it escaped might give a clue.Any evidence of a previous  failure,different texture or colour in the failed section.I find it odd that cruising along at minimal load and bang.Be good to get definitive numbers on this.I defiantly need something to think about just before nodding off to sleep at night.
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Vince, goes like this in answer to your questions.
All models can break a rod, in both 120 and 180 engines, Series 1 and Series 2, klms make no difference, all cylinders, is a lucky dip, sometimes you even get two at once as I have a crank here that I bought with two broken rods on it, both outers, 1000's and 1200's do it, breaks between the little end and the big end  :D, generally breaks at lowish revs, once it breaks it can escape from the front, top, bottom or rear, or any combination of the above depending on how fast the rider shuts the engine down, rarely see different texture in the break but never sent one off for stress analysis at a lab which is what one should do but costs money to get done properly, a lot of money.

Told you to install the Carrillo conrods when we built your crank.

 
Hi Red,

Sounds like you are saying it's a sensible idea to replace the rods with Carillos.....what sort of cost for a crank tear down a triple crank & rebuild with a set of Carillos?

Cheers

Pete
 
Yogi,

Terrible bad luck!
I almost wish I hadn't read this and seen the photos - I'm about to put the cylinders & head back on my TS- original bottom end.....
Now I'm nervous.

Regards,
Steve
 
poffer said:
Hi Red,

Sounds like you are saying it's a sensible idea to replace the rods with Carillos.....what sort of cost for a crank tear down a triple crank & rebuild with a set of Carillos?
Cheers
Pete
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Pete,
You would be better off asking Keith for a price, no use sending me a crank from the UK, freight alone both ways will add 400 quid at least
and my prices vary depending on if it is a 180 crank (good price) or a 120 crank (more expensive price) or rephrasing a 120 back to 180 which attracts a massive discount  :D

 
You would be better off asking Keith for a price, no use sending me a crank from the UK, freight alone both ways will add 400 quid at least and my prices vary depending on if it is a 180 crank (good price) or a 120 crank (more expensive price) or rephrasing a 120 back to 180 which attracts a massive discount   :D
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Thanks Red,  I would have gone to Keith in a heartbeat - just didn't know he rebuilt cranks.  I will drop him a line and sort something out.

Of course, "they are all 120s being rephased to 180"  :D

Cheers

Pete
(p.s. understand about the shipping - they are heavy little suckers.  :P )
P
p.p.s. Just checked Keith's site - found the crank rebuild bit. I must have missed it as it was nested in the services page - didn't realise there were extra tabs (oops  ::) Sorry Keith )
P
 
redax5 said:
rephrasing a 120 back to 180 which attracts a massive discount  :D
Click to expand...

Red

Well that's a very interesting retrograde modification you offer there. I was intrigued so I did a bit of google'ing and found a picture of the kind of guy that would commissioned such a travesty job...

T.


twat.+check+the+tags_139b21_3843530.jpg
 
Told you to install the Carrillo conrods when we built your crank.


[/quote]

Yes you did,still kicking myself.Good to see your back in the frame. When people say when renovating that whatever is to expensive to do at the time I usually remind them its a one off cost that needs to last basically forever,should have taken my own advice.
 
Sitting here feeling smug, thinking about my nice new Carillo rods. A definite topic for a philosophy discussion - there had to be a reason I left those fuel taps on and trucked my engine. ::)
 
when I had Yogi's bike here in Calgary for a bit, I went through pretty much everything EXCEPT the bottom end. Such a low km engine with a known local two owner history from new, only 31,000 kms total roughly, and the second owner the Laverda dealer who had sold the bike new and then took it back on trade and kept it.

when Yogi and I were chatting on the phone yesterday I did mention to Yogi that when I picked the bike up from the seller with my trailer and then first checked it over, the valve clearances were all out a bit, with the exception of one valve which had "negative clearance'. The valve could never close completely and presumably is how the bike had been running for some time before it was put away for its long hibernation.

I have now checked my work log for the bike, the valve with the negative clearance was the intake valve on the center cylinder. When the bike left me I had all the valve clearances as close to factory spec as I could make them. I wonder if the center cylinder being ridden by the second owner with an intake valve clearance so far out of spec that it could never fully close had anything to do with the subsequent center rod failure, or whether the rod failure would have happened even if the valve clearances ahd always been maintained perfectly?

Such a shame, it really is a beautiful bike, I was sad to see it leave Canada, while happy for Yogi at the same time!

Paul LeClair
 
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