Strada Camshaft Oil Ways

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Jordan
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Re: Strada Camshaft Oil Ways

Postby Jordan » Sun Apr 05, 2020 10:07 pm

Just to mention it, I knew someone who fitted extra coil springs to his twin, which was tuned for extra road performance.
Soon afterwards, he reported both camshafts and all rockers were destroyed.
Could it be that the later 860s had harder parts? It doesn't seem likely, but...

Duccout
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Re: Strada Camshaft Oil Ways

Postby Duccout » Mon Apr 06, 2020 7:15 am

Those with long memories may recall Cook Neilsen writing in 'Cycle' about how the desmo system was essential in bevel twins, because of the damage that '10000 rpm valve springs' would do to the top end. The problem is that the coil springs are so short, just compare them with the length of springs on Japanese bikes. I remember Anthony Ainslie telling me that he had gone through the entire spares catalogue of Kawasaki bikes in an effort to find a coil spring to use in Ducati singles, but they were all too long.

Duccout
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Re: Strada Camshaft Oil Ways

Postby Duccout » Tue Apr 07, 2020 5:56 am

http://www.mhttp://www.motoscrubs.com/f ... ew&id=5179
Here are some pictures of my valves. The inlet shows the worst distortion and wear - the knife edge at the outside of the seat is sharp enough to cut you, and has worn a ring deep into the seat in the head that has proved very difficult to remove.
You do not have the required permissions to view the files attached to this post.

Duccout
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Re: Strada Camshaft Oil Ways

Postby Duccout » Wed Apr 08, 2020 3:05 pm

Stop Press: latest instalment! I decided that I'd take a look in the clutch, which showed quite a lot of wear on the hub and basket, indicating a high mileage; I'm beginning to wonder if my engine is not on the original piston, but has had a new barrel and piston.

More drama during the inspection: both the engine oil filter and crank end plug were seized solid in the threads, and the Allen head recesses rounded off; I ended up resorting to a hammer and chisel to free them off, while worrying about cracking the cases, which thankfully did not happen. Removal of the oil drain revealed that no filter is fitted; wonderful, just what I wanted to see and now I've got to add a new filter to the ever-growing list of parts needed.

Ventodue
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Location: Montpellier, France

Re: Strada Camshaft Oil Ways

Postby Ventodue » Wed Apr 08, 2020 3:53 pm

It's certainly giving you the run round, this one, Colin. Ever going to buy a Spanish import again? :twisted:

Duccout
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Re: Strada Camshaft Oil Ways

Postby Duccout » Wed Apr 08, 2020 4:20 pm

Craig, l think it has taught me what I already knew, it is always better to buy a good, running bike than to take a punt on an unknown quantity. I assumed that whatever I bought, it would be the major engine components that would be the biggest expense - big-end, piston, but I never imagined that the engine would have been butchered so badly; if I replaced every dodgy part the bill would have been thousands already.

LaceyDucati
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Re: Strada Camshaft Oil Ways

Postby LaceyDucati » Wed Apr 08, 2020 8:53 pm

Hi,
My guess is that engine has been run on unleaded fuel without any additive.

The double springs are a little heavy and combined with poorly finished rockers (both in plating and flatness) and poor oil, pick up can occur. That said I've seen Spanish engines running fine with those coils. For a road engine (and some race) I'm with Jon using hairsprings.

Running a cam without a restriction or blank will restrict oil flow to the rockers. That subject has been discussed before on this forum.

My experience from race engines is using an oil with suitable additives goes along way to maximise longevity of cams and rockers. I won't enter the mineral, synthetic, mono grade, multigrade argument as all have proved satisfactory in my experience.

The Twin outer springs are very comparable at full lift pressure to the 3.6mm hairsprings. The 3.8mm hairsprings are considerably heavier at full lift. Generally speaking most aftermarket coil springs utilised in Ducati bevel engines have far less pressure on the seat than the hairsprings. The problems only arise at full lift with some coil springs especially at low revs as often used with road engines. With race engines at high revs the load is minimal as inertia in the valve components takes over. Bevel race engines will (if appropriate) rev happily and reliably in excess of 10000rpm with correctly specified coil springs. Sorry I don't buy into the Desmo Myth, regarding bevel engines....... even though I've built some fast desmo engines :-)

Seat wear is always more excessive with hair springs as the valves cannot rotate due to the fact that the valve, collets and top retainers are invariably locked together.

Using bevel twin outer springs on their own in a single should work fine for road use with a modest cam like the white cam. I have had a few batches of twin outer springs manufactured. Not sure I still have any left but they can be sourced from couple of suppliers. The spring fitted height for twins is not stated anywhere in any manuals or information I have seen. I do have a figure I use but would have to look it up.


Just my pennies worth.....

Regards Nigel

Duccout
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Re: Strada Camshaft Oil Ways

Postby Duccout » Wed Apr 08, 2020 9:30 pm

Thank you for your thoughts Nigel. It did cross my mind that maybe unleaded fuel had played a part in the valve damage. The other consideration is were the valve clearances maintained? The valves were sunk so far into the seats that the owner would have needed to adjust the clearances every week, and the adjusters were screwed right out. If the exhaust rocker had been run for any length of time holding the valve open, I imagine that it would have accelerated wear on the rocker face and the cam lobe.

Ventodue
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Re: Strada Camshaft Oil Ways

Postby Ventodue » Thu Apr 09, 2020 11:11 am

Good stuff as always, Nigel. Thanks for sharing your experience - and for finding the time to do so.

George
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Location: Essex UK

Re: Strada Camshaft Oil Ways

Postby George » Thu Apr 09, 2020 11:23 am

Ventodue wrote:Good stuff as always, Nigel. Thanks for sharing your experience - and for finding the time to do so.


I second that makes interesting reading.
My list of replacement parts for Nigel is getting longer each day
George Essex UK


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