Sufficient Break-In Mileage For Synthetic Oil???

wireman wrote: Well as many times as I change the oil after rebuilding a motor it would be really expensive/waste of money to use synthetic.
I change it after 30 minutes of running ,then again at 500 miles .

baldy110 wrote:

bountyhunter wrote: You can switch anytime, you can run syn from the start. It's a myth that engines won't break in using synthetic oil.

Is this from personal experience? My own experience from rebuilding engines is I have never managed to get the rings to seat using synthetic oils. I end up taking the top end apart re-honing the cylinders then reassemble and break in again with conventional oils. After about doing that 3 times on 3 different engines I no longer break in using synthetic oils. I have never had a problkem breaking in rings with conventional oils.
To answer the OP's original question, yes you can switch at 1200 miles. I usually wait until I have 1000 miles on a fresh engine then switch if I want to.

kaw-a-holic wrote: I use Lucas full synthetic motorcycle oil. They also have a partial synthetic if you are still on the fence about the break in period. I also use the fuel additive to keep the top end lubed. When the bikes came out we still had lead in gas which lubricated valves. It also keeps everything clean. I run Lucas in everything with a motor. Just my opinion.

bountyhunter wrote:

baldy110 wrote:

bountyhunter wrote: You can switch anytime, you can run syn from the start. It's a myth that engines won't break in using synthetic oil.

Is this from personal experience? My own experience from rebuilding engines is I have never managed to get the rings to seat using synthetic oils. I end up taking the top end apart re-honing the cylinders then reassemble and break in again with conventional oils. After about doing that 3 times on 3 different engines I no longer break in using synthetic oils. I have never had a problkem breaking in rings with conventional oils.
To answer the OP's original question, yes you can switch at 1200 miles. I usually wait until I have 1000 miles on a fresh engine then switch if I want to.

I base it on the fact that some high end new cars are running full syn from day one.

vintagebiker wrote: I don't recommend a full synthetic oil, Use a semi/senthetic oil, and one made just for motor cycles. Full synthetic oil can cause your clutch to slip and burn out. Automotive oil doesn't have the molecule shear additive in it like motorcycle oils have, due to the transmissions running in the same oil as the engine oil. The gears shear the oil molecules very quickly if it is not motorcycle oil.

vintagebiker wrote: I don't recommend a full synthetic oil, Use a semi/senthetic oil, and one made just for motor cycles. Full synthetic oil can cause your clutch to slip and burn out. Automotive oil doesn't have the molecule shear additive in it like motorcycle oils have, due to the transmissions running in the same oil as the engine oil. The gears shear the oil molecules very quickly if it is not motorcycle oil.

Choosing a Break-In Oil for Your Motorcycle

The theory that synthetic oils should not be used during break in is the same as the theory that your engine will break in better if you use synthetic oil but add a dinner candle to your four quarts of engine oil. Frankly, I find this theory, um, questionable. Oh, hell, laughable. Corvettes and Porsches come from the factory with Mobil-1 in their engines. Remember, these engineers have designed world-champion engines for F1, Indy, Le Mans 24 hours, etc.

There's a lot of mythology surrounding break-in oil. It's simply not the case that synthetic oils are more "slippery" than conventional oils. Also, break-in of a modern engine is completely different than break-in of an engine made before about 1980. Modern engines, by comparison to something made in the '60s, are pretty much already broken in from the factory due to the fact that today we hold much tighter machining tolerances. The exception, of course, would be the Ural, a motorcycle made on a production line unmodified since about 1935.

bountyhunter wrote: For the record, it's generally not the oil which fails due to motorcycle usage, it's the additives specifically viscosity increasers (VI's) which are long polymer molecules. Running the oil through the gears in the tranny chops them up over time and your 10-40 oil gradually turns into 10W oil. Some of the better new oils have stronger VI's.

An advantage of pure synthetic oil is that it takes very little VI additive to make it track the multi grade viscosity profile, so it has less additives in it. In that regard, true syn is actually better suited for bike usage.

general oil info;

www.calsci.com/motorcycleinfo/Oils1.html

same reference as to why I doubt the "synthetic won't break in" :

Choosing a Break-In Oil for Your Motorcycle

The theory that synthetic oils should not be used during break in is the same as the theory that your engine will break in better if you use synthetic oil but add a dinner candle to your four quarts of engine oil. Frankly, I find this theory, um, questionable. Oh, hell, laughable. Corvettes and Porsches come from the factory with Mobil-1 in their engines. Remember, these engineers have designed world-champion engines for F1, Indy, Le Mans 24 hours, etc.

There's a lot of mythology surrounding break-in oil. It's simply not the case that synthetic oils are more "slippery" than conventional oils. Also, break-in of a modern engine is completely different than break-in of an engine made before about 1980. Modern engines, by comparison to something made in the '60s, are pretty much already broken in from the factory due to the fact that today we hold much tighter machining tolerances. The exception, of course, would be the Ural, a motorcycle made on a production line unmodified since about 1935.

bountyhunter wrote:

Choosing a Break-In Oil for Your Motorcycle

There's a lot of mythology surrounding break-in oil. It's simply not the case that synthetic oils are more "slippery" than conventional oils. Also, break-in of a modern engine is completely different than break-in of an engine made before about 1980. Modern engines, by comparison to something made in the '60s, are pretty much already broken in from the factory due to the fact that today we hold much tighter machining tolerances. The exception, of course, would be the Ural, a motorcycle made on a production line unmodified since about 1935.