The ozzies old enough will remember the Castrol GTX story from an Early Castrol 6 Hour Production Endurance race and the Bevel Ducati that almost won one year, did a big end in the last 30 minutes while leading the race. And then we have the friction modifiers that bike wet clutches didn't like. Both things are said to be down to GTX. That was a long time ago, and I expect oil companies have learned a lot since then. Is this what people say is an oil thread? Does anyone use synthetic? Did I go there? What about Caster? Rip that scab off.
20 50 mineral-based break in engine oil?
- Thread starter TeddyG
- Start date
F500fan
Full member
- Location
- Croydon, Surrey
Totally agree !
Oil the bores & rings as a minimum. Spin the motor with plugs out, preferably with rocker/cam cover off to see if you actually have flow to the top of the engine.
If you can connect an oil pressure gauge just to be sure, then by all means do so.
You need to be 100% certain the oil is going & doing exactly what it's supposed to !
It's the engine's life blood. Any issues could result in failure. Why take the chance ??!!
It only takes a small blockage, perhaps an unseen piece of debris, or a gasket fitted incorrectly & blocking an oil way.
I'd rather take the time to know, than to take that chance !!
TeddyG
Hero member
- Location
- Portland Oregon
My concern about which oil to use for break in was because the last pair of new Ross pistons developed severe wear after 1600 miles, using Bel Ray 20 50 mineral oil.
I had the mineral oil analyzed by Speed Diagnostics and was told the oil had lost viscosity and to NOT use mineral after the break in. I researched and contacted ALL the major oil companies and found most of their “ break in” oils w higher zinc content (that supposedly help rings to seat in better) are not designed for wet clutches. Others told me ( including here) to just use mineral for the break in.
So I decided to use Motul 3000 20 50 Mineral, and will change it within 300 miles w/ the same, and then use Motul 20 50 full synthetic. I thoroughly cleaned the freshly honed cylinders w dish soap several times, coated the bores w oil and primed the oil pump before starting it. So far, so good, and will do a compression test after the break in.
Many thanks to everyone’s input.
I had the mineral oil analyzed by Speed Diagnostics and was told the oil had lost viscosity and to NOT use mineral after the break in. I researched and contacted ALL the major oil companies and found most of their “ break in” oils w higher zinc content (that supposedly help rings to seat in better) are not designed for wet clutches. Others told me ( including here) to just use mineral for the break in.
So I decided to use Motul 3000 20 50 Mineral, and will change it within 300 miles w/ the same, and then use Motul 20 50 full synthetic. I thoroughly cleaned the freshly honed cylinders w dish soap several times, coated the bores w oil and primed the oil pump before starting it. So far, so good, and will do a compression test after the break in.
Many thanks to everyone’s input.
F500fan
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- Location
- Croydon, Surrey
When you say the pistons developed severe wear, was that just to the rings or actual scoring on the pistons as well ??
As I mentioned in an earlier post, tolerances & clearances play a big part.
I trust everything was checked to be within those limits before the rebuild ??
Phew. I was thinking what comes out of this thread. I suggest something like Motul 5100 20W-50 for regular use, also the mineral 3000 can be used longer. If there would be problems the root cause is elsewhere.
In Finland we stopped using Bell Ray in 1980's after their shock oils had problems with viscosity stability.
On these 750's the oil rises up on the cylinder head close to the exhaust ports causing the oil to heat up quite much, secondly the valve train was originally designed for the 650. At least after some changes this caused too high contact pressures on the valve train. These cause the 750 being very demanding for the used oil. In Finland we got the most usual valve train issues solved quickly (far before I was even born) by drilling the additional spray holes that were missing on the early production, and using engine oils of quite strictly chosen spec and then changing the oil regularly.
I suggest to use the standard running-in method for standard pistons and rings, and Ross' instructions for their pistons and rings.
On running-in and testing results on this forum has often such a problem that the scope was too short, and often some of the taken actions were for compensating other problems that can be sorted correct way separately to actually disappear.
Not sure if the "drive it like you stole it" suggests that an engine should not be even warmed up, I would not go on this one. Usually big motorcycle engines require around 10 kms of traffic drive before they are mostly heated up.
-Jouni
Ian Short
Full member
- Location
- Cambridge Ontario
1200ts specifies that it is the bore and ring set that is put together dry. It simply aids in bedding the rings to the bore and providing quicker ring seal. I've assembled many air cooled engines this way and run them on conventional oil and never had issues.
The major contributor to engine longevity is careful assembly, proper warm up cycle and maintaining proper oil change intervals.
piranha-bro2
Hero member
- Location
- Melbourne
Problems with 750 cams and rockers was far more likely to have been caused by oil starvation due to blocked feeds to the rocker spindles through the stud holes. My SF1 didn't have the feed holes the factory began drilling for the SF3 (1975) and there was no serious wear in the top end at 160,000km when i swapped everything to SFC spec and the later type forged rockers.
As an ignorant 19yo I never did anything special in terms of oil type and changes intervals. I personally think there's way too much 'science' being thrown around when it comes to running in and oil type. I know it's not an oil thread but I have run fully synthetic oil in my motors since Mobil 1 came on the market. Wet clutch - no problem, even with a big power and torque increase with the 880. Before that we I ran Mobil Delvac diesel oil. Never had a problem.
It will be interesting to see how Teddy's new engine goes. I sincerely hope the problems with his first set of brand new pistons and bores weren't due to a still-undiagnosed issue elsewhere.
As an ignorant 19yo I never did anything special in terms of oil type and changes intervals. I personally think there's way too much 'science' being thrown around when it comes to running in and oil type. I know it's not an oil thread but I have run fully synthetic oil in my motors since Mobil 1 came on the market. Wet clutch - no problem, even with a big power and torque increase with the 880. Before that we I ran Mobil Delvac diesel oil. Never had a problem.
It will be interesting to see how Teddy's new engine goes. I sincerely hope the problems with his first set of brand new pistons and bores weren't due to a still-undiagnosed issue elsewhere.
Ian Short
Full member
- Location
- Cambridge Ontario
Bingo...... I would be far more concerned about the condition of the oil pump and circuits as the cams are essentially running on "plain bearing journals". Getting oil, whatever the flavour, to the top end is the name of the game. The rest of the engine is on ball or roller bearing which require just a mist of oil.
As an aside, a good friend who used to build and race XR750 Harley's told me that at idle the oil pressure was under 5psi and wound up to 7000rpm he was trying to get it below 10psi.
Nobody has even mentioned the critical importance of the cylinder hone.......... lots and lots of important things going on.
Roller and ball bearings tend to live happier and longer lives in conventional motor oils.......... bearing skid is real.
And as always, my opinion is worth exactly what you paid for it.
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F500fan
Full member
- Location
- Croydon, Surrey
Not sure if the "drive it like you stole it" suggests that an engine should not be even warmed up, I would not go on this one. Usually big motorcycle engines require around 10 kms of traffic drive before they are mostly heated up.
-Jouni
Nobody has said "drive it like you stole it", just drive it as normal, but don't overload or over rev.
As regards "warming up". If you JUST warm the engine, then you're still trying to drive a COLD gearbox & final drive !
Warm them TOGETHER at the SAME TIME by setting off at an easy pace, BUT, as mentioned previously, DON'T OVERLOAD by UNDER or OVER REVVING. You don't ever see a footballer or runner only doing leg warm ups before a match or sprint do ya ??!!
Those are NOT my words, but the wise words passed on to me by a very experienced mechanical engineer !
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F500fan
Full member
- Location
- Croydon, Surrey
That is all well & good, but only provided that the tolerances & clearances have been checked to be within the specified limits.
Is the bore true from top to bottom ?
Were the ring gaps checked at top, middle & bottom ?
It only takes a small discrepancy to create a bigger problem !
F500fan
Full member
- Location
- Croydon, Surrey
I did mention the critical importance of tolerances & clearances in an earlier post, which pretty much covers everything from correct gasket thickness. Oil pump wear & output. Trueness of the bores. Piston & ring fit. Cams, valves, buckets & shims etc etc.
It all depends on whether it's been built to the "...nth degree", or with a "little bit" of slack.
But whatever the spec, you gotta find the correct oil for the job !
And as has previously been mentioned, if you consider how the manufacturer punted them off the production line, & you've managed to get tens of thousands of miles from your pride & joy simply by following the maker's guidelines, why complicate things by overthinking !!
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Mastroianni
Full member
- Location
- TOULOUSE FRANCE
I use the cheapest mineral 20W-50 oil because, in Europe, all these oils meet the same EC (European Community) specifications—standards shared by everything from the cheapest to the most expensive brands.
It’s the same story with my Vespa PX; I’ve never had any issues.
In my humble opinion, the pricier ones rely on marketing-driven additives to justify a higher price point that appeals to the target audience's psychology.
I prefer changing the oil more frequently instead.
I own a 1970s Alfa Romeo, and I’ve always been advised to use mineral 20W-50 oil in that worn engine; the concern is that synthetic oils might dislodge old deposits and create sludge that could damage the engine.
However, synthetic oils work fine in engines that have been completely rebuilt.
It’s the same story with my Vespa PX; I’ve never had any issues.
In my humble opinion, the pricier ones rely on marketing-driven additives to justify a higher price point that appeals to the target audience's psychology.
I prefer changing the oil more frequently instead.
I own a 1970s Alfa Romeo, and I’ve always been advised to use mineral 20W-50 oil in that worn engine; the concern is that synthetic oils might dislodge old deposits and create sludge that could damage the engine.
However, synthetic oils work fine in engines that have been completely rebuilt.
You can try a search "ride it like you stole it" on the search field on the upper right corner. The amount of hits may surprise.
I know this is the suggestion to put baling wire inside engine and then to file the stud holes loose on the top cover.
Anyone ever thought why the top cover has such a tight holes and what actually happens when the cover is tightened in place?
henrywillms
Hero member
- Location
- Canada
Teddy I really do feel for you on the problems you had with the rebuild and desire to get it right this time. I hope the Forum has been a good help to you.
Many experts have spoken on the oil and I won't contradict them........BUT my suggestion is used oil from a proven genuine Laverda source. I just changed the oil on my Corsa and your welcome to it. My bike ran really good on it and it only has about 1,000 km (600 miles) and it looks kind of golden brown with maybe a bit of black in it. Pretty good used oil if you ask me, and it's free!
Many experts have spoken on the oil and I won't contradict them........BUT my suggestion is used oil from a proven genuine Laverda source. I just changed the oil on my Corsa and your welcome to it. My bike ran really good on it and it only has about 1,000 km (600 miles) and it looks kind of golden brown with maybe a bit of black in it. Pretty good used oil if you ask me, and it's free!
piranha-bro2
Hero member
- Location
- Melbourne
The distance front-to-back of the holes in the top cover seem to vary, Jouni - imprecise factory machining? I never used wire for years on my SF1 and had no problems, and even with wire I didn't need to elongate the holes. I have a different cover now, but as cheap insurance I always fit the thin wire to any twin motor I build anyway. Because there are no dowels to position the top cover onto the head precisely it is random where the studs will end up relative to the top oil-feed channel. Covers that require elongating - we're talking very small amounts here - just to enable the thin wire to be fitted, were obviously on the risky side when fitted without the wires.
What worried me about Teddy's previous build and premature wear, was whether the feed to the crank-slingers-pins-bigends-cylinders may have been compromised - and I don't know whether this has been checked prior to doing the whole job again with new Ross pistons. Fingers crossed.
You mean that the distance of the holes on the cover vary from cover to cover? Front-back, but not sideways?
As the cover has no dowel pins and should find a some kind of average condition how the studs are leaning on the tight holes.
The oil channels are not inline with the stud holes:
-On left and front the stud should be leaning left and back
-On left and back the stud should be leaning left and front
-On right and front the stud should be leaning right and back
-On right and back the stud should be leaning right and front
I was thinking:
1. How many of them could do this at the same time? I guess possibly just one. The passages should then be blocked on both sides, because on the analyzed damages in Finland the valve trains had always similar damage on both sides. No cases with damages on one side only.
2. The difference in stud diameter vs. hole diameter should keep the channel open even if the stud is leaning against the passage. However, this can form a narrow slot, that could get blocked if there is sludge. The damages are also known in very clean engines. I once tried to calculate this blocking, but I did not had all of the real components with actual dimensions on hands at that moment. My approximation was that the area was still bigger than the area of the oil spray holes - when a stud is leaning against the passage with the cover tightened in place. Also the oil channels not being inline with the holes widens the passages.
3. How the wire solution was actually tested? My understanding is that in Finland the damaged cases cut sharply off, and success for decades for dozens of bikes.
-Jouni
F500fan
Full member
- Location
- Croydon, Surrey
Have you considered a graphite engine rebuild paste like this, for those first few revolutions of the engine while the oil finds it's way round after a rebuild ?
piranha-bro2
Hero member
- Location
- Melbourne
I use graphite based assembly paste on cams and rockers only. Yoshimura cams used to come with a little tube of it. No way i'd used it on pistons or rings.
And plugs out, spin on the starter for a bit and oil will be up and ready to do its thing.
And plugs out, spin on the starter for a bit and oil will be up and ready to do its thing.