Old bike, new engine -synth or dino oil?

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G'day,
I am trying to work out what to do. Here's why: I am running a 1985 FJ1100 air cooled bike as a commuter. I have always changed oil every 5000kms, The engine I have in there at the minute has only 17,000kms on it. The old engine got up to 250,000kms before burning a valve and I discovered all the valve guides were buggered. Anyway, as my current engine is possibly the newest engine I have ever had, I am wondering what to do.

I have been told here and there, that the old air cooled engines have fairly wide tolerances to manage the wide temperature ranges that they get exposed to. In this line of thinking, a few people have stated that synthetic oils may be overkill in such an engine, as synthetics are ideally designed for modern engines with very small tolerances, and very little room for even a small amount of "sludge". Whereas with the older engines, Dino oil may be just as effective, as long as oil changes are frequent, as any benefits Synthetic oils can offer.

So, without starting a massive oil thread, I just want to gauge what people think. I am happy to keep using Dino oil, as I got 250,000kms from the last engine, and I reckon Dino does just fine. However, if people reckon Synth is the best alternative, keeping in mind I use the bike everyday, so not much chance of crud buildup per se, change oil frequently, I am keen to be educated...

cheers, Gareth
 
The service manual calls for 10W-30 & 20W-40 depending on the temp range. I don't know what brands you have available in Victoria, but I'd suggest a full syn for an air cooled engine for resistance to thermal breakdown & coking.
 
Synthetics transfer heat better considering where you are. Some people are using Rotella Oil, T6 (Rimula 4 or 6) it should be a cheaper alternative some people are using Valvoline VR1 20-50.
 
At a 5000km change interval, you can run either one no problem. The good synthetic would hold up better over the interval, but a good mineral oil shouldn't be totally spent that quickly either.
 
Synthetic is advertising hype to part you and your money. It won't make your engine run better or last longer. I run dino in 110 to -20 degrees F outside air temp. Synthetic does nothing for me that dino won't. My turbo engine is approaching 300k miles, all on cheap api certified dino. The oil industry has done a good job brainwashing a few to use synthetics. It's your money.
 
Originally Posted By: sprite1741
Synthetic is advertising hype to part you and your money. It won't make your engine run better or last longer. I run dino in 110 to -20 degrees F outside air temp. Synthetic does nothing for me that dino won't. My turbo engine is approaching 300k miles, all on cheap api certified dino. The oil industry has done a good job brainwashing a few to use synthetics. It's your money.


Your engine oil dosnt run through your transmission like on bikes and that shreds oils. If it didnt do duel purpose I would mostly agree except Syns do control heat better.
 
I'd be all over Penrite products were they available around here.
A good amount of JASO MA certified oils to choose from, in all viscosities you can imagine.
I'd personally first try a 15w40 HDEO if consumption was not an issue.
 
Syn doesn't do much better when looking at the motorcycle UOAs or do the cars UOAs
 
G'day,
I appreciate all the good offerings here, there is alot to consider I suppose. So far I am inclined to remain with Dino, just perhaps spent a little more on the brand and change more often, perhaps every 3000kms, and do the filter every other change.

cheers, Gareth
 
I had a '93 FJ1200, about 20 years ago. I tried 10w40's, but it always seemed happier on synthetic 15w50. The old FJ can get HOT, a bit higher viscosity isn't a bad idea under your conditions.

Incidentally, that is one bike I regret selling.
 
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If the last engine gave you 250k on 5k oil changes, why on Earth would you want to change at 3k intervals?

Edit: quick calculation. If an oil change costs you 20 bucks, and you get 250k on 5k changes, and even 300k on 3k changes, that's exactly double the oil changes over the life of the engine. Or should I say 1000 bucks more for 50k more miles (not guaranteed, just a guess expecting you get more life out of it, but who knows). Is it worth it without knowing for sure it extends engine life?
 
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"If the last engine gave you 250k on 5k oil changes, why on Earth would you want to change at 3k intervals?"

Well, since oil technology, even with cheap oils, has improved a great deal since the bike got it's first oil change, increasing the oil change interval would most likely provide a very real increase in engine protection. The cost is less than you estimate as well. I use cheaper oil, so changing more frequently adds negligible cost, and the oil I am using these days is car oil, so again, increasing change intervals may help insure against how quickly car oil may shear due to it's use in a motorcycle gearbox.

The reason I have been using car oil, is I got sick of paying around $38AUD for 4 litres, whereas I can pick up a reputable brand for $15 on special.

"The old FJ can get HOT, a bit higher viscosity isn't a bad idea under your conditions."

I am currently using 15W 50, as it can get hot, up to 44 degrees Celsius, and you are right, the FJ is capable of cooking a valve just idling too long in the heat!?
 
You could do a blend and stay with 5k oil changes. My next change im going to run rotella T5 15w40 blend. Its about 17 bucks a gallon.
 
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