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Discussion Starter · #1 ·
I was told to post this here instead of Supersport, so here goes.
Bike in question is a 1980 900 SSD. I pulled it out of a garage in the mountains of Colorado from the original owner, with 10,000 miles on it, parked in 1984 on the original tires along with everything else down to the bill of sale from the dealer and every single service record, tool in the tool kit, and manual.

It's getting the normal treatment of fuel lines (green), fuel petcocks, full carb rebuilds, a bunch of misc old rubber pieces, oil and filter, tires, brake lines and caliper rebuilds, exc.

My questions:
1) Oil. I know, I know. Everyone's favorite game show. Oil threads. But, searching resulted in no newer information and some conflicting results. So. What oil is everyone running now? I run Castrol 20W-50 Non-Synth in my BMW Airhead and K. I see recommendations for straight 50, which for Phoenix isn't a huge deal but it's still not my favorite, and recommendations for 20w50 non-synth. Can I get away with 20w50 Castrol on 1000mi oil changes?

2) Carbs are obviously PHF 32's, what size float needle valve are people running? 250? I'm ordering the kit from BevelHaven with the choke assembly as well.

Thanks in advance, here's the bike:
 

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G'day mate,

I run Penrite 50 in my bevels.
Maybe others might have changed what they use, but my understanding is that stock engines have low oil flow rates and need the extra viscosity.

Sorry not sure about the needle valve size but I can check if need be.

Good score lad, this is not a BM, different beasty.
Rossco:nerd:
 

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A very good but now retired old Duc bevel tech says that 40 or 50w oil is the proper oil for the old bevels since they have roller (not plain) crank bearings and the tolerances were done using yardsticks. He also added that the choice is somewhat weather and rider dependent in that you should go to thinner 30w oil when it's cold, but he also added that if you're not hammering the bike a 20-50w is fine. Since I now pussy around on my bevels, I run the 20-50w but change it a lot. Interestingly, since it has an oil filter, he said to run 15-50w Mob 1 for my MHR Mille. So, think hard as to how the bike is being used and make your choice.
 

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Discussion Starter · #4 ·
A very good but now retired old Duc bevel tech says that 40 or 50w oil is the proper oil for the old bevels since they have roller (not plain) crank bearings and the tolerances were done using yardsticks. He also added that the choice is somewhat weather and rider dependent in that you should go to thinner 30w oil when it's cold, but he also added that if you're not hammering the bike a 20-50w is fine. Since I now pussy around on my bevels, I run the 20-50w but change it a lot. Interestingly, since it has an oil filter, he said to run 15-50w Mob 1 for my MHR Mille. So, think hard as to how the bike is being used and make your choice.
Well it's going to be ridden, but not incredibly hard, and I'd prefer the cold engine wear protection of 20w50. BevelHeaven sells Motul, so I might go with that. I run Mobil 1 for the Porsches and the Jeeps, and pretty much everything else, it's good oil, but Synthetic in older engines cause issues.
 

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The Australian importer of Ducati bevels in the 70s learnt the hard way about the correct oil to use. The big ends failed in racing and robbed the brand of a win in a prestigious 6hr race after 5&1/2 hours. Straight 50 is what should be used. My bevel has Castrol DD 50. Not cheap but cheaper than a rebuild. Congrats on the find. Cheers
Ian
 

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Right, please don't all jump on me, this is just my contribution and I don't expect everyone to agree, but that's fine. After a lifetime of running bevels (over 40 years) and reading multitudes of expert advice and arguements, here is what I believe.

Mineral multigrade should not be used, due to the breakdown of the chain polymers. In hot countries SAE 50 is the correct grade and according to Silkolene oil here in the UK a medium detergent oil should be used, not a low detergent oil, as would be used in a vintage engine with no filtration at all. Sae 50 is not suitable in colder climates, due to the poor cold performance which will result in top end wear.

After 40 years of using SAE 50 in summer and changing it every autumn for a multigrade, I ran out of enthusiasm and consulted Lacey Engineering, the UK's top bevel tuners, Nigel told me that he has used Silkolene Comp 4 20/50 (synthetic) in all his race engines for years with no wear evident and much better results than anything else. I switched to this oil and my engines ran quieter and there is no need to change between summer and winter.

If you Google 'George MTS' who was (now sadly deceased) a top oil technician, you can read his thoughts on oil and he categorically states that no mineral oil can compete with synthetic, which does not degrade appreciably in use and does not use chain polymers to achieve its multigrade status. The problem to look out for in choosing a synthetic oil is the low levels of ZDTP (zinc phosphate) which is added to oils to prevent wear of 'rubbing' parts, but has been gradually phased out in oils that are used in vehicles with a catalytic converter. We need high levels of ZDTP in our older engines, so pick an oil that is not suitable for cat equipped engines (in Europe SG or lower,and with an A or B classification, NOT C ). I believe that in the USA Mobil 1 15/50 or 20/50 fulfills the requirements for bevels, although I haven't checked the technical make-up recently to see if ZDTP has been reduced.

A high mileage engine that has been run on low detergent oil may have built up levels of sludge in the crankcase, in which case it must continue to be run on low detergent oil. This can be checked by inserting a long screwdriver through the oil filler and scraping the bottom of the crankcase. If sludge is present (which is very unlikely these days) then it will be collected on the blade of the screwdriver.

Feel free to disagree with me, it's an open forum and we all have a view.
 

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Thanks Rossco! Oil is one of those subjects where there is no real definitive answer, but I did a lot of research and asked some very technical techs over the years and that is what I came up with. SAE 50 is a very good oil with great lubricant qualities, but only in warmer climates. After that you are in multigrade territory and no mineral multigrade can hold a candle to a synthetic, as long as it is intended for older engines. You are lucky in Australia as you can just use SAE 50 and forget it. Penrite does a great 50 which really suits bevels too.
 

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Oh, Colin is so right! Pretty much, "'Nuff said", except to add:

Ducati first specified synthetic multigrade oil in ...

March 1976 in the 860GTS supplement to the 860 owner’s manual (1st issue).

The problem was that at the time no-one - or at least very few - grasped the implication of synthetic, as in "AGIP SINT 2000". And mineral multigrade is just not up to the task.

Btw: 10-50 is what Ducati specified for the SSD - and it's what you need. The reason is simple: the lower viscosity reduces the load on the starter motor when it's cold - and the starter clutch on these bikes is a weak spot.

They wear relatively quickly - no surprise there: it's a friction device. And they particularly don't like being driven backwards - no surprise there either: they're a one way clutch. So get a battery with LOTS of cold cranking amps and keep it well charged. Otherwise you risk backfires, forcing the clutch in the wrong direction.

Quick summary :laugh:. Play nice: use a quality synthetic of the specified viscosity and change it at least every 5,000 kms to get rid of combustion by-products. Ducati specified every 3,000km. But modern oil improvements mean you can extend that a little.

HTH

Craig

SSD owner - even better than a MHR. I had one ...
 

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Bike in question is a 1980 900 SSD.
That's a very fine example you've got there. Congratulations! To find one with the original screen is very rare. Look after it.

My questions:
1) Oil. I know, I know.
Already 'Asked and Answered' (I hope!)

2) Carbs are obviously PHF 32's, what size float needle valve are people running? 250?
250 is correct. However, just be aware that two different versions of the PHF32 were fitted. You probably have the CD version which is critically different from its predecessor, the AS/AD type, particularly as regards the idle screw. Steve at Bevelheaven knows all this, tho'. Just let him know which you have and he'll see you right.

Thanks in advance, here's the bike:
If you can let me have the frame and engine numbers and date of build or first registration, I'd appreciate it. Nothing sinister - I just keep a little register, you see ... :laugh:

Ciao

Craig
 

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... my understanding is that stock engines have low oil flow rates and need the extra viscosity.
Quick one, Rossco. No, quite the opposite in fact. Roller bearing engines need to flow like a fully open tap - ever seen a gear gazer in action? It's impressive ... But they do so without any pressure - which is why mounting a pressure gauge on a bevel is pretty pointless and also why fitting a potentially obstructive full-flow paper oil filter should be ... thought about very carefully before implementation.*

Ign. Taglioni may not have always got it right, but he did know a thing or two ...

An oil with low viscosity at ambient temperature is not in itself a problem. But because mineral oils thin when they get hot, it's courting disaster :surprise:. (And as you know, mineral multigrades are a very partial and unreliable solution to the problem). Hence the specification, before synthetics came along, of a gloopy monograde 40 or 50 grade for the singles and the 750s.

Ok, it made them harder to start when cold - but hey! Just kick harder, yer pussy ... Or move to somewhere warmer.

The game changed completely when electric starters came along. These really struggle to turn over a Bevel Twin with 40 or 50 monograde oil. (Remember how absolutely pathetic - and expensive! - lead-acid batteries used to be?) Synthetics offered an answer ... It's no surprise then that Ducati started specifying synthetic oil with the electric start version of the 860, their first main-line bike to be so fitted (a few late model 750s had one, but that was right at the death of the line).

If you want to be nice to your engine today, you use a super clingy, synthetic 'multigrade'. Of course, they're not really 'multigrade' at all - it's just that the old system of rating mineral oils was transferred to synthetics, even tho' it makes no sense. The all important difference is that synthetics retain (more or less ...) the same viscosity regardless of temperature. So a synthetic can have a viscosity which is the equivalent of (say) a mineral oil of 10 at ambient temperature and also of 50 at high temperature.

* I own a Zané Laverda. I know what problems can result ... (eek!)
 

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Discussion Starter · #13 ·
Thank you all for the input. I'm in Phoenix, AZ so I don't think we have what you would call a "Cool" Climate, but for the next few winter months I've decided to run with the recommended 20-50 to ease the starter motor and to hopefully get oil into the valves a little quicker as I'm testing and tuning the bike back to life. About May when we start seeing those 85-90 degree days (And the bike is running well) I will switch to a straight 50W. Again I appreciate the insight!.

That's a very fine example you've got there. Congratulations! To find one with the original screen is very rare. Look after it.


Already 'Asked and Answered' (I hope!)



250 is correct. However, just be aware that two different versions of the PHF32 were fitted. You probably have the CD version which is critically different from its predecessor, the AS/AD type, particularly as regards the idle screw. Steve at Bevelheaven knows all this, tho'. Just let him know which you have and he'll see you right.



If you can let me have the frame and engine numbers and date of build or first registration, I'd appreciate it. Nothing sinister - I just keep a little register, you see ... :laugh:

Ciao

Craig
Yep, they are CD carbs, luckily he drained and treated the tank and emptied the carbs going into storage, so luckily I'm not chiseling old gas out.

Thank you! I'm excited to ride it. I've had a 748 and a 996, but the early 900 was always my "Dream bike." Wasn't looking for one, but in the super small town in Colorado I grew up in word got to me that, "A gentleman had an old Italian bike that he was thinking about selling" and as soon as I saw it, I bought it. He had owned the bike from new and I have a copy of the original title, But it's not in front of me for original Date of sale- it was sold by from Rissmann Motors in Albuquerque, NM.

Here's the information that I have!
Frame No: 950857
Engine No: 904596
Date of build: 12/79
 

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You'll find the Darmah a bit different to the 748 and 999, more like a vintage bike or (say it quietly) a Harley, all low down power and torque. You may not like it, they are an acquired taste. One thing that you must get right to make it run properly is the throttle synchronisation, which must be spot-on or it will run very lumpy. IMO vacuum gauges are a must.
 

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Here's the information that I have!
Frame No: 950857
Engine No: 904596
Date of build: 12/79
Many thanks for that. Yours is one of a fairly large batch that were built in November-December 1979 and went to the States, most being registered in early 1980.

Here are the numbers that I have around yours - one with a frame number just one away from yours, one with an engine number just two away!

950846 904644 U.S.A.
950851 904565 U.S.A.
950856 904589 U.S.A.
950857 904596 U.S.A.
Not known 904598 U.S.A.
950860 904600 U.S.A.
950861 904601 U.S.A.
950874 904614 U.S.A.
950886 904532 U.S.A.

The first bike in the list belongs to Steve Allen, btw!

Ciao

Craig
 

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I've decided to run with the recommended 20-50 ... <snip>
About May ... I will switch to a straight 50W.
I guess I may not have been clear enough. The oil that Ducati recommended for the SSD was a synthetic 10-50. See the relevant attached page from the Owner's Handbook.

So NOT 20-50, NOT monograde. It's your call, but I can think of no reason why you should wish to do different.
 

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Discussion Starter · #17 ·
I guess I may not have been clear enough. The oil that Ducati recommended for the SSD was a synthetic 10-50. See the relevant attached page from the Owner's Handbook.

So NOT 20-50, NOT monograde. It's your call, but I can think of no reason why you should wish to do different.
My apologies, I must of missed that. I'll find a 10-50 Synth, I guess I should've thumbed through my owners handbook to start out with.
 

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Discussion Starter · #18 ·
Just out of curiosity, what brand were you running in a 10w50 Synthetic? I'm seeing an offering from Motul: https://www.motul.com/lb/en/products/7100-4t-10w50

and an offering from Castrol: https://www.amazon.com/Castrol-10W-..._feature_keywords_three_browse-bin:6397047011

I agree synthetics hold weight better, ie. don't break down, and on short interval oil changes it's not a big deal. I was under the impression that I should avoid synthetic motorcycle oil because the clutches in the bevels didn't like it even with the friction modifiers.

That offering from castrol looks like it has a ton of detergents, and the Motul seems like more of what I'm looking for.
 

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I'm sure the Motul would be good. I'm currently using Mobil 1 4T Racing, the 15-50 version ('tis near enuf :)). There is also a 10-40.

Clutch slips normally occurs when people use car oils. Bike oils don't contain the same friction modifiers. But if you do get it, all that is need is to take the plates out, wash them in kerosene or similar, rough up the friction plates and reinstall.
 

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A really high quality dino oil you could consider is Brad-Penn, it is available in both 20w50 and straight 50wt. It is the same as the old GT1 Kendall , "The green oil" and has the high ZDDP and phosphorus that engines love. I used it for years when I was racing my bevel and never had any issues with wear. It is available online and not real expensive. With the lack of real filtration I do 1000mi. oil changes and can't justify spending the money on synthetics.
 
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