supergizzman
XS400 Enthusiast
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Wondering if its a good idea to run synthetic oil in my 400 any thoughts??
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thoughts on running synthetic oil
- Thread starter supergizzman
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Won't hurt anything....but why?
RevrdMark
XS400 Addict
well synth is VERY slippery so on old bikes where normal oil has worked well Synth will seep around slightly warn gaskets and produce leaks that may never have been there before
..and dislodge sludge due to modern detergents and send it round the engine to score your camshaft bearings.
Score, 
Penalty, 
go back crack the crank case, and replace the bearings,
That sounds worse than a 
poke in the eye. What the He!! you only live once. Its your bike, till your the PO.
I guess I would not be very afraid of knocking sludge loose- I've used products actually designed to do that and never had a problem. I think that is a view of synthetics that persists, but I wonder how often it is actually an issue.
Personally, I would not use synthetics, but for another reason- with a 2000 mile change interval, which you still need in a 30 year old, air-cooled bike with a shared sump, all you are going to do is spend more money for little to no realized benefit.
Personally, I would not use synthetics, but for another reason- with a 2000 mile change interval, which you still need in a 30 year old, air-cooled bike with a shared sump, all you are going to do is spend more money for little to no realized benefit.
And too slippery (added, modern "friction modifiers") is also supposed to be bad for wet clutches, non?
consensus is, if you rebuild the engine, using synth or semi synth is ok so long as you can afford it.
If the engine is old, then there will be negatives to that as mentioned above.
If the engine is old, then there will be negatives to that as mentioned above.
Jeremy Corbin
XS400 Member
Based on the Mobile1 FAQ it appears that there are NO friction modifiers in the Full Synthetic motorcycle oil. Mobile appears to be fully aware that many bikes use a common sump with wet clutches. They boast that they use detergents though. Isn't the oil filter supposed to be catching the "gunk" anyway? Isn't that it's job?
Based on this information I see more advantages of running full synthetic than disadvantages. I'll probably run it for 1000mi and then do a full oil change with filter to get all the "gunk" out and then continue to run it.
Based on this information I see more advantages of running full synthetic than disadvantages. I'll probably run it for 1000mi and then do a full oil change with filter to get all the "gunk" out and then continue to run it.
Okay then, if you feel that way, I just strongly recommend to look for the "MA" listing on the bottle of oil. All MA stands for, "Wet Clutch compatible" Some of us use Diesel oil, others use YamaLube. I dont remember the rest. Look on the Shell Rotella Triple T, on the Second line down, in the list of Letters, you will find MA at the end of that line. Go forth and experiment. I am okay with this one, cause its only (still) $3.64 at my local walmart. (quart).
lcgtr
XS400 Addict
I used Motul expensive synthetic on my Commando of the correct weight and its glazed up the bores and it blows smoke now. Apparently quite a common result on early british bikes I find out now.
I have to pull it down to hone it
I have to pull it down to hone it
XSLeo
XS400 Junkie
Synth oils are not slipperier than dyno oils. Slippery is based on the weight of oil.A 40w dyno is just as slippery as a 40 w synth.
The main difference between dyno and synth oils is the molocules that make up the oil.
Dyno oil is like going into a river bed and scooping up a hand full of the stones in the bottom. You will find stones of many sizes and shapes.
Synth oil is more like scopping up a handful of marbles, all the molocules are the same size and shape.
With dyno oil the sludge that builds up are the bigger bits of the oil that get stuck and can't move around easily. The detergents used in oils picks up some of this sludge and keeps it suspended in the oil so it gets carried to the filter.
Synth oils with even sized molocules, it gets under more of this sludge and this helps the detergents do thier job better. It's this extra cleaning that can get gaskets to leak.
Most modern dyno oils don't sludge up like the old single weight and early multi wieght oils did so this leaking is much less the 30 years ago.
On your Commando I don't think the cylinders got glazed from the synth oil. It is more likey that the synth oil cleaned out most of the sludge that was keeping your worn rings sealing.
How long have you been running the synth oil? It may take a few miles for the rings to reseat to the bores.
On my XS's I use a dyno oil and change it at 1000-1500 mile intervals. The oil filtration isn't that grt on these old bikes. On my 2003 Harley the filtration is much better as well as having the engine oil just engine oil, I run much longer change intervals. I use Amzoil 20w50 and run at least 5000 miles sometimes as much as 6500-7000 miles.
That's about once a year.
Using oil that costs $14 a quart won't go in a bike that gets oil changes at 1000 miles. A good $5 a quart oil works just fine.
Leo
The main difference between dyno and synth oils is the molocules that make up the oil.
Dyno oil is like going into a river bed and scooping up a hand full of the stones in the bottom. You will find stones of many sizes and shapes.
Synth oil is more like scopping up a handful of marbles, all the molocules are the same size and shape.
With dyno oil the sludge that builds up are the bigger bits of the oil that get stuck and can't move around easily. The detergents used in oils picks up some of this sludge and keeps it suspended in the oil so it gets carried to the filter.
Synth oils with even sized molocules, it gets under more of this sludge and this helps the detergents do thier job better. It's this extra cleaning that can get gaskets to leak.
Most modern dyno oils don't sludge up like the old single weight and early multi wieght oils did so this leaking is much less the 30 years ago.
On your Commando I don't think the cylinders got glazed from the synth oil. It is more likey that the synth oil cleaned out most of the sludge that was keeping your worn rings sealing.
How long have you been running the synth oil? It may take a few miles for the rings to reseat to the bores.
On my XS's I use a dyno oil and change it at 1000-1500 mile intervals. The oil filtration isn't that grt on these old bikes. On my 2003 Harley the filtration is much better as well as having the engine oil just engine oil, I run much longer change intervals. I use Amzoil 20w50 and run at least 5000 miles sometimes as much as 6500-7000 miles.
That's about once a year.
Using oil that costs $14 a quart won't go in a bike that gets oil changes at 1000 miles. A good $5 a quart oil works just fine.
Leo
lcgtr
XS400 Addict
Ive been running that oil in the commando for about 1000km. I put HPR40 in it on Friday and the Synth oil that came out was as black as the ace of spades so you might be right there.
I gave it a good thrashing and the reports are by the end of the ride that is was blowing a lot less smoke. The science doesnt make much sense to me to be honest but all those I have spoken to agree its the oil and say its glazing..... It may be for the reasons you stated as that makes more sense. Ive also heard of people running diesel oils through petrol engines to clean them up for the high detergent levels in diesel oils.
I gave it a good thrashing and the reports are by the end of the ride that is was blowing a lot less smoke. The science doesnt make much sense to me to be honest but all those I have spoken to agree its the oil and say its glazing..... It may be for the reasons you stated as that makes more sense. Ive also heard of people running diesel oils through petrol engines to clean them up for the high detergent levels in diesel oils.
XSLeo
XS400 Junkie
On the Harley it came with dyno oil. It went back to the dealer for the 1000 mile check up. The put dyno oil in it then. At around 4000 miles I changed the oil to Amzoil 20w50. The dyno oil was in there just a few thousand miles. I looked at the dip stick after just few hunderd miles and the synth oil was black as coal. I ran it 5000 miles and changed it. It took a bit longer to turn black.
It took about three oil changes to get the synth oil to stay clean. Now it takes about 2000 miles before the oil starts to color up much.
So even in just a few thousand miles dyno oil can dirty up an engine. So on an older engine with 20-30,000 miles it may take longer.
I might ru it awhile before I tear it down and freshen up the ring.
Many on here that get a bike that has sat for a few years, when they first get it the compression is low and uneven. They get it running and after a 100 miles or so the compression comes up and evens out.
The rings weren't sealing well at first but reseat after running. This is a simular process you using the synth after dyno oils. Takes a while to clean out the old and let the new work.
Many use diesel oils because of the high ZDDP levels. This helps protect the cam and rocker arms. Most deisel oils are wet clutch approved.
If you look at the label on the back of an oil bottle you will find a list of ratings. Often the last one is a JASO MA This is the wet clutch rating. If the oil has this rating it means the oil has ben tested and approved for wet clutches.
There are many good oils without this rating that work fine with wet clutches, they just have not gone through the testing to get the rating.
Most deisel oils and motorcycle oils have this rating.
On using car oils in your bike. The lighter weights like 5w30 or 10w30 have friction modifiers in them that are not good for wet clutches. These oils have the starburst emblem and say energy saving on them. The heavier like 10w40 or the 20w50 oils don't have these additives and no star burst, energy saving markings. These can be used.
In my 750 kitted XS650 I run a blend of Valvolene 20w50 race car oil and Valvolene 20w50 motorcycle oil. One quart of the race oil then enough of the bike oil to top it up.
I used Pennzoil 20w50 car oil for a few years, but Walmart Quit selling it. It worked fine in the stock bikes but the extra HP of the 750 kit, the clutch slipped. In the stock bikes I use the Rotella T 15w40 deisel oil. Most places have it for around $13 a gallon. You can get it in bigger jugs, like 5 gallons and save a bit of money.
Leo
It took about three oil changes to get the synth oil to stay clean. Now it takes about 2000 miles before the oil starts to color up much.
So even in just a few thousand miles dyno oil can dirty up an engine. So on an older engine with 20-30,000 miles it may take longer.
I might ru it awhile before I tear it down and freshen up the ring.
Many on here that get a bike that has sat for a few years, when they first get it the compression is low and uneven. They get it running and after a 100 miles or so the compression comes up and evens out.
The rings weren't sealing well at first but reseat after running. This is a simular process you using the synth after dyno oils. Takes a while to clean out the old and let the new work.
Many use diesel oils because of the high ZDDP levels. This helps protect the cam and rocker arms. Most deisel oils are wet clutch approved.
If you look at the label on the back of an oil bottle you will find a list of ratings. Often the last one is a JASO MA This is the wet clutch rating. If the oil has this rating it means the oil has ben tested and approved for wet clutches.
There are many good oils without this rating that work fine with wet clutches, they just have not gone through the testing to get the rating.
Most deisel oils and motorcycle oils have this rating.
On using car oils in your bike. The lighter weights like 5w30 or 10w30 have friction modifiers in them that are not good for wet clutches. These oils have the starburst emblem and say energy saving on them. The heavier like 10w40 or the 20w50 oils don't have these additives and no star burst, energy saving markings. These can be used.
In my 750 kitted XS650 I run a blend of Valvolene 20w50 race car oil and Valvolene 20w50 motorcycle oil. One quart of the race oil then enough of the bike oil to top it up.
I used Pennzoil 20w50 car oil for a few years, but Walmart Quit selling it. It worked fine in the stock bikes but the extra HP of the 750 kit, the clutch slipped. In the stock bikes I use the Rotella T 15w40 deisel oil. Most places have it for around $13 a gallon. You can get it in bigger jugs, like 5 gallons and save a bit of money.
Leo
