Synthetic oil in rebuilt engine?

[80GS1000]

Not another synthetic oil thread, you might be thinking.



But seriously, when can you start using synthetic in a rebuilt GS motor? I broke in the rebuilt 1000 motor (new Wiseco pistons and bigger cams) with Valvoline motorcycle-specific 10w/40 dino oil and am wondering when I can switch to my elixir of choice, Mobil 1 Racing 4T. I tend to ride it like it's stolen and it gets pretty hot here in the summer so synthetic worked well in the bike before the motor rebuild. The Mobil 1 had the smoothest shifts out of any oil tried.

[tkent02]

If you have been riding it hard it is probably pretty much worn in at several hundred miles, I would wait a few thousand if it were me. Get the rings sealing as tightly as they possibly can.

[Steve]

I don't know if they do any special engine prep, but some cars come from the factory with synthetic oil.

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[Nessism]

I wouldn't be afraid of synthetic in a new engine. Just load the rings and you will be fine. Synthetic is not more slippery, it just lasts longer.

If you really want to learn about oil, go over to the Bob Is The Oil Guy forum. Interestingly, oil analysis reports from people using synthetic oil rarely come back showing less wear (metal bits in the oil) than the dino oils. If there was actually less friction in engines using synthetic oil there would be less metal in the oil...but there isn't. http://www.bobistheoilguy.com/forums/ubbthreads.php

[Tarbash 27]

I will be running regular 10/40 for the first I guess 3,000 mils before I switch to Amsoil motorcycle 10/40.

[duaneage]

Biggest advantage of synthetic is shear strength at higher temps. It can take 400-450 degrees while dead dinos goes to 325 or so. It also lasts longer and has no sulfur or paraffin. Not many oils have zinc anymore, it was real helpful for these engines while it lasted.

[Nessism]

Biggest advantage of synthetic is shear strength at higher temps. It can take 400-450 degrees while dead dinos goes to 325 or so. It also lasts longer and has no sulfur or paraffin. Not many oils have zinc anymore, it was real helpful for these engines while it lasted.

Oils still have zinc, just less of it - about 20% less than a few years ago.

[Plooker]

a couple of thoughts

I'm fully in favor of using synthetic oil right off the bat. Harley uses synthetic oil in the 'screaming eagle' models right from the factory. Same basic motor design, roller bottom end, chain drive cams, etc. as a GS. as a harley mechanic I've had the opportunity to tear down a couple of these motors with 3000 and 10000 miles respectively. Both had basically no wear evident. I run Amsoil, because I can get it cheap through the shop, but any synthetic is a great way to prolong your enjoyment of your machine, good in the gearboxes on shafties also.

[drhermanstein]

get the thing broken in, Throttle on and off with slight load in 2nd 3rd and 4th and after 1000 mi and maybe two oil changes in there check compression at the same time. Then switch if it stops increasing.

[Old Colt]

The oil used at startup really depends on the cylinders surface finish and the rings used. If you use chrome rings you need dino oil.

With a smooth finish and coated rings the bores are essentially bedded in and you can go directly to synthetic. I do say "can" but it may still be better to start with dino.

I do know of a number of people who have drained the synthetic out of there new cars and run dino for 1K and switched back to the synthetic with good luck.
One of my customers has a twin turbo Porsche that has been consuming oil since new, Synthetic from the factory. Five years now and leaks past the rings, dealer says it is quite normal. The cats have been replaced twice, yup that sounds normal to me. That engine never broke in. He has just bought a Nissan GTR to replace it and just has snow tires on the Porsche now.

[bonanzadave]

$ ?

How much is that Mobil 1 ? I just saw an ad in Cycle World for Royal Purple.
MSRP $16.00 a qt ! Ouch.

[trippivot]

I say 3000 ~5000 miles on the new rings then go to synthetic oil.
the oils are so good you need to wait until there is a little mechanical wear for the fluid to fit into.

all this is just my opinion. I use standard Kendall oil for the higher zinc level.
I use web cams and that is the suggested oil for their products.

[Nessism]

I say 3000 ~5000 miles on the new rings then go to synthetic oil.
the oils are so good you need to wait until there is a little mechanical wear for the fluid to fit into.

all this is just my opinion. I use standard Kendall oil for the higher zinc level.
I use web cams and that is the suggested oil for their products.

Back when Kendall was Kendall (before the name was sold several times and eventually wound up being acquired by Conoco-Phillips), their oil had lots of zinc (1600 ppm vs. 900 which is common these days in auto oil). Now a days though Kendall oil is just like the other Conoco-Phillips oils being sold by their gas stations - which is good oil but nothing like the old stuff. On the Bob is the oil guy forum there is an oil analysis report of new type Kendall oil and there is only 770 ppm zinc.

Honestly, there are so many silly urban legends regarding oil that it's amazing. If anyone really wants to cut through to the truth, go to the oil forum and start reading.

And regarding using synthetic oil in a GS engine, I think it's a good idea because synthetic oil has excellent high temperature properties which is good for air cooled engines. Ironically, it's the loaded touring riders that will benefit the most; long oil change intervals are possible since synthetic oil doesn't brake down as fast as dino, and the high temp capabilities are appropriate for loaded touring, particularly if you get stuck in city traffic.

[rustybronco]

I will be running regular 10/40 for the first I guess 3,000 mils before I switch to Amsoil motorcycle 10/40.

Matt, try 20w50 amsoil m/c oil in the warmer temps. I like the little edge between 40 and 50.

[Zook]

One, synthetic oil IS slipperier than dino-how do you think it decreases friction?

Two, synthetic oil can be either paraffin based stock or polyester based stock.

Three, there is "synthetic" oil-that is, super-refined dino oil, such as Mobil1, Valvoline, etc, that the government allows to be CALLED synthetic (Group IV) and then there are the TRUE synthetics (Group V), such as Red Line, Royal Purple, and Amsoil.
And they have combinations of both, too.

Those engines coming from the factory with synthetic in them have been run on a dyno with conventional oil in them before filling them with synthetic.

The EPA now limits the levels of zinc. Oils like Rotella have higher levels than others, but no more than the EPA allows. If you want more, you have to go to the true racing oils (not the stuff at Auto Zoo, like valvoline racing), but like Royal Purple, etc. Since it is made for actual racing applications it is not limited by the EPA.