Posted: Wed Apr 25, 2007 8:53 am
Well, my bike doesn't sit still for 3 months at a time and it doesn't get used to poodle around for short bits in town either.
Synth does not make a bike use more oil. What can happen is that the 15W50 is too thin when cold, causing more use when starting and running untill it is hot. Going back to 20W50 will solve this.
What also can happen with an older bike that has been running dyno oil for years, that synth dissolves the deposits left by the dyno oil. If certain engine parts have worn out, like valve stems, these deposits can keep it from burning oil for a while. The cleaning of the synth will remove the deposits and it will start using oil. Going back to dyno will have no effect at all, as the deposits are already gone and it will keep using oil untill the defective parts have been replaced. Which makes it a bad idea to put synth in an older higher mileage bike that has always been running dyno.
My S uses oil, as does just about every boxer. Experimenting showed the type of oil does not change this. What does change this is for instance heavy engine braking in the mountains. Oil consumption will jump. Leaving the mountains and/or less engine braking will reduce oil consumption to normal levels. This is caused by the huge vacuum created by the cylinders on closed throttle, sucking oil past the piston rings into the cylinder.
But by far, typically the most oil 'use' in a boxer is the blowback into the airbox.
My bikes get fresh oil every 12,000km and not a second sooner. Shit, even my old 1974 CB400F got that treatment, and it had 120,000km on the dial by the time I totalled it.
Of course if you do a lot of short rides and the engine doesn't always get to operating temps, it is wise to change oil more often. If you use your bike normally, it is perfectly ok to change later. If you only do long distances, it is just plain silly to not to. My VFR ran Motul 300V esther based full synth, and it got changed every 16,000km. I sold it with 52,000km on the dial and it never used a drop of oil or did anything other then run perfectly.
Do as you wish and makes you happy but please don't kid yourselves. These modern engines are spec'd to the point of dealing with severe abuse and still survive. If the spec is 8,000 miles, it is not going to fail at 8,100. You are likely to be able to run it for 10k more with the cheapest oil you can get without experiencing any immediate ill effects. There are margins builtin, and those not built on the best oil you can get but rather the most common, cheap oil you can get.
Synth does not make a bike use more oil. What can happen is that the 15W50 is too thin when cold, causing more use when starting and running untill it is hot. Going back to 20W50 will solve this.
What also can happen with an older bike that has been running dyno oil for years, that synth dissolves the deposits left by the dyno oil. If certain engine parts have worn out, like valve stems, these deposits can keep it from burning oil for a while. The cleaning of the synth will remove the deposits and it will start using oil. Going back to dyno will have no effect at all, as the deposits are already gone and it will keep using oil untill the defective parts have been replaced. Which makes it a bad idea to put synth in an older higher mileage bike that has always been running dyno.
My S uses oil, as does just about every boxer. Experimenting showed the type of oil does not change this. What does change this is for instance heavy engine braking in the mountains. Oil consumption will jump. Leaving the mountains and/or less engine braking will reduce oil consumption to normal levels. This is caused by the huge vacuum created by the cylinders on closed throttle, sucking oil past the piston rings into the cylinder.
But by far, typically the most oil 'use' in a boxer is the blowback into the airbox.
My bikes get fresh oil every 12,000km and not a second sooner. Shit, even my old 1974 CB400F got that treatment, and it had 120,000km on the dial by the time I totalled it.
Of course if you do a lot of short rides and the engine doesn't always get to operating temps, it is wise to change oil more often. If you use your bike normally, it is perfectly ok to change later. If you only do long distances, it is just plain silly to not to. My VFR ran Motul 300V esther based full synth, and it got changed every 16,000km. I sold it with 52,000km on the dial and it never used a drop of oil or did anything other then run perfectly.
Do as you wish and makes you happy but please don't kid yourselves. These modern engines are spec'd to the point of dealing with severe abuse and still survive. If the spec is 8,000 miles, it is not going to fail at 8,100. You are likely to be able to run it for 10k more with the cheapest oil you can get without experiencing any immediate ill effects. There are margins builtin, and those not built on the best oil you can get but rather the most common, cheap oil you can get.
. I prefilled the engine to just below the MAX indication, with the engine being cold. After a ride, the indicater was just above the MAX indication. Another 
There's an oil thermostat and if it's closed (engine cold or not fully warmed up) it'll restrict oil flow back to the sump when the engine's switched off. But if left overnight in most cases the oil will find its way back gradually.