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I use Castrol syntec in my Jetta TDI and go 10,000 miles between changes. I put syn on my HD and the service rep said see ya in 4,000 miles. Why do we use synthetic in our HD's and change it like regular oil? It should go at least 8,000 miles or use the regular oil in place of it and spare the cost.
 

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Hmm, interesting comparision

VW 1.9L TDI - 100hp, 177 ft lbs, 1896cc 3000lb vehicle, 45mpg, 10k mi oil change

Harley TC96 - 68hp, 85 ft lbs, 1575cc, 900lb vehicel, 40mpg, 5k mi oil change

Vehicles with both engines, when well cared for, last forever and are a pleasure to drive.
 

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dusty67 said:
I use Castrol syntec in my Jetta TDI and go 10,000 miles between changes. I put syn on my HD and the service rep said see ya in 4,000 miles. Why do we use synthetic in our HD's and change it like regular oil? It should go at least 8,000 miles or use the regular oil in place of it and spare the cost.
With regular oil the manual for my 2005 says 5,000 miles. With a GOOD synthetic you should be able to go 7,500 miles.

With your Jetta you should be able to just change your filter every 10,000 miles and ADD REPLACEMENT OIL. Then at 100,000 miles you change everything out with a complete oil and filter change.
 

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Bigtwin101 said:
How many cyl. does your Jetta have? and is it water cooled?
Good point, but still a good question. Why would you use an oil that is supposed t last longer, for the same length of product that doesn't last as long?


Also why would the service manager recomend 4k when HD recomends 5k on dino?

I do 4-5500 on mine with syn. The reason I say 5500 is cause I don't alwasy get to it by 5k. In fact at about 4950 right now.
 

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dusty67 said:
I use Castrol syntec in my Jetta TDI and go 10,000 miles between changes. I put syn on my HD and the service rep said see ya in 4,000 miles. Why do we use synthetic in our HD's and change it like regular oil? It should go at least 8,000 miles or use the regular oil in place of it and spare the cost.
The biggest reason is the possibility fuel dilution/shearing of the oil, which is something these engines seem prone to. Unfortunately, fuel will not simply evaporate out of the oil and will cause a premature breakdown of its lubricating ability. Still, you are also getting the really important benefit of the higher flashpoint of synthetic oil and its ability to withstand extremely high engine temperatures. As you know, the rear cylinder of your Harley has very poor airflow and cooling.

I also have a VW TDI and have gone as far as 20,250 miles on an oil change. Through regular analysis, I monitor my engine's health and opted for a normal change interval of 15,000 miles.
There's really no reason a synthetic oil can't go much longer in a motorcycle if oil analysis is used. That's assuming that there are no mechanical problems with the engine. I'm using Mobil 1 V-Twin in the wife's 2007 Sportster and will only get about 4000 miles on the oil before the bike is put away for the winter. I plan to use analysis to determine if I can go farther between oil changes next year when we'll be able to put more miles on the bike.

Just something for you to consider. Hope that answers your question.

Max
 

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I agree with the fuel contamination info. The fact is...crankcase oil gets contaminated with all kinds of crud..fuel, dirt, etc...after 3K I change my crankcase oil without regard to how many miles the tranny or primary have on them. I know I can go 10K on both of those without a problem. I know this because of how clean the oil is at 6K. But, for me, I will continue to change crankcase at 3K and tranny and primary at 6K. I use M1 20/50 V-twin synthetic in the crankcase and primary and M1 syn 75/90 gear oil in the tranny. Works great, lasts a long time.

The crankcase oil is dirty stuff at 3K....change it then...dino or syn. Take it to 5K if you want but to me...3 quarts at $8.50 a quart is cheap insurance for my 1995 EVO motor....that doesn't leak a single drop and uses less than a half quart in 3K miles....probably only about 4 ounces.
 

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Max Q said:
The biggest reason is the possibility fuel dilution/shearing of the oil, which is something these engines seem prone to. Unfortunately, fuel will not simply evaporate out of the oil and will cause a premature breakdown of its lubricating ability. Still, you are also getting the really important benefit of the higher flashpoint of synthetic oil and its ability to withstand extremely high engine temperatures. As you know, the rear cylinder of your Harley has very poor airflow and cooling.

I also have a VW TDI and have gone as far as 20,250 miles on an oil change. Through regular analysis, I monitor my engine's health and opted for a normal change interval of 15,000 miles.
There's really no reason a synthetic oil can't go much longer in a motorcycle if oil analysis is used. That's assuming that there are no mechanical problems with the engine. I'm using Mobil 1 V-Twin in the wife's 2007 Sportster and will only get about 4000 miles on the oil before the bike is put away for the winter. I plan to use analysis to determine if I can go farther between oil changes next year when we'll be able to put more miles on the bike.

Just something for you to consider. Hope that answers your question.

Max
So the saying goes, and if you don't have oil analyzed you are just guessing...
After 6,000 the TBN (oil additives) are still only half gone!:harhar:


:corn:

Tom
PS: I suspect the comment on gas in the oil was because this sample is from last March and the bike sat 4 months before I got around to servicing. I ran it for a short time to warm up the engine just before changing the oil.
 

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Life has come full circle.

Where does the average guy get oil analysis? Is it worth the time and money, or better off just changing?
 

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Doesn't matter if the "additives" are only half-gone at 6K miles. The fact is, the oil is contaminated with crap way before that. Drain your oil at 3K, 4K, 5k, or 6K miles. It's always dark and dirty from the crankcase. Why is that? It's because of the junk that an air-breathing (dirt), vented-to-the-atmosphere, fuel-getting-past-the-pistons, V-Twin engine introduces into the crankcase oil.

If you want to do the oil analysis that is great but just because oil doesn't have wear metals that are over the thresh-hold doesn't mean the oil isn't dirty.

Just sayin...I would continue to change it at 3K. Not trying to knock other lines of thinking. It is so easy to change and serves to keep an engine like new.
 

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dusty67 said:
I use Castrol syntec in my Jetta TDI and go 10,000 miles between changes. I put syn on my HD and the service rep said see ya in 4,000 miles. Why do we use synthetic in our HD's and change it like regular oil? It should go at least 8,000 miles or use the regular oil in place of it and spare the cost.
First, your air-cooled Harley runs at a much higher oil temp than your VW. Common temps near 300F will cause fairly rapid oxidation of your mineral oil. A synthetic oil will break down more slowly at these higher temps (than those seen in a water-cooled motor). Also, synthetic oil will yield dramatically lower wear rates than non-synthetic oil because it simply lubricates better. You dont need to use it, but you will wear out your engine faster without it. IMO, the additional cost is worth prolonging the life of my engines.

The factors contributing to drain intervals are numerous, but includes those mentioned by others above and factors like the effectiveness of the crankcase vent system, the oil sump volume and many others. If youd like to know exactly when to change, oil analysis is the way to go indeed.
 

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steveusmc said:
Doesn't matter if the "additives" are only half-gone at 6K miles. The fact is, the oil is contaminated with crap way before that. Drain your oil at 3K, 4K, 5k, or 6K miles. It's always dark and dirty from the crankcase. Why is that? It's because of the junk that an air-breathing (dirt), vented-to-the-atmosphere, fuel-getting-past-the-pistons, V-Twin engine introduces into the crankcase oil.

If you want to do the oil analysis that is great but just because oil doesn't have wear metals that are over the thresh-hold doesn't mean the oil isn't dirty.

Just sayin...I would continue to change it at 3K. Not trying to knock other lines of thinking. It is so easy to change and serves to keep an engine like new.
@gree: Some years ago, I took part in an all-inclusive oil study run by GM to determine: advantages of syn oil, necessary oil change intervals and ranking of non-syn oils. The outcome was surprising. Granted, the oils were tested in multi-cylinder, water cooled engines, so perhaps the change intervals shouldn't be assumed to apply to air cooled twins, but the interesting thing from the study was this. Synthetic oils did result in what some reviewers suggested might be better lubrication (Just a clinical observation. No scientific proof). BUT, all oils got dirty at the same rate, and it was the contamination in the oil that drove oil change intervals, not the loss of lubricity or thermal breakdown.

Likewise, I've heard a number of riders swear that as soon as they put syn oil in their HDs the motors made less noise or "ran smoother" and maybe that's true, although I didn't have that experience. But if it's up to me (which it is with my Super Glide), I'll opt for oil change intervals every 5k and spend less on carbon-based oils. It worked for almost 100 years of Harleys before syns came along.
 

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steveusmc said:
You must be from rural, IL..........somewhere like Mascoutah. :xhere:
At one time ('bout 35 yrs ago) - but not anymore, jarhead.

I moved up the road towards the capitol so I could be closer to my tax dollars.:laugh:
 

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14-O said:
@gree: Some years ago, I took part in an all-inclusive oil study run by GM to determine: advantages of syn oil, necessary oil change intervals and ranking of non-syn oils. The outcome was surprising. Granted, the oils were tested in multi-cylinder, water cooled engines, so perhaps the change intervals shouldn't be assumed to apply to air cooled twins, but the interesting thing from the study was this. Synthetic oils did result in what some reviewers suggested might be better lubrication (Just a clinical observation. No scientific proof). BUT, all oils got dirty at the same rate, and it was the contamination in the oil that drove oil change intervals, not the loss of lubricity or thermal breakdown.
Likewise, I've heard a number of riders swear that as soon as they put syn oil in their HDs the motors made less noise or "ran smoother" and maybe that's true, although I didn't have that experience. But if it's up to me (which it is with my Super Glide), I'll opt for oil change intervals every 5k and spend less on carbon-based oils. It worked for almost 100 years of Harleys before syns came along.
Thats why I just use the dino stuff. There are plenty of shovels still on the road, and panheads too (re: PRE-syn oils). Rebuilding is probably cheaper than spending 4X every 3K miles, but thats splitting hairs. If one uses syn, and does any more to his engine than stage 1, then its likely he'll be doing more maintenance on the engine down the road anyway. A hopped up engine will (almost) always wear faster than a stocker.
 

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14-O I'll opt for oil change intervals every 5k and spend less on carbon-based oils. It worked for almost 100 years of Harleys before syns came along.[/QUOTE said:
So did kickstarts for 80 of those years. Times change, bikes have gotten better, and I hope they keep doing so.

As far as oil analysis goes, if you have acess to it, it is probably the most relible thing to do. I used to take care of 2526hp cat generators, we used oil analysis to determine if we need to change oil. I am not up on everything involved, but I think its going to tell you what you got better then eye balling it.

I agree its cheap insurance, and most of us don't have the time/patience, or access to testing
 
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