noise possibly? i know with full synthetic my last 2 bikes sounded like commercial grade sewing machines.... i ended up switching to the synthetic blend and have been
happyand a lot of the people i ride with feel the same way.

 

Consider this, the synthetic manufactures say you can run say 50% longer between changes for the sake of argument. Going with HD's recommendation of a 5k service they only do two services with synthetic as opposed to three with conventional oil in a 15k mile span. That is probably why they are pushing conventional, drums up more service appointments.

 

IMHO whether you use dino or syn oil makes no difference. Change the oil and the filter at recommended intervals and all will be fine. It's cheap insurance.

 

Honestly i don't think it's to big off difference. My dad has run Dyno oil since he bought his FXR new in 1990. Now his bike is 22 years old with 86k miles and still running the original motor and trans. Probably if he ran synthetic the mechanical noise of the motor would be quieter, but I think it fits the nostalgic of the old FXR.

Even though my dads bike is a proven fact that Dino oil is fine I still run synthetic. One because I like the quieter motor noise and two I'm an amsoil dealer and that's what I run in all my vehicles.

I believe with todays standards run what you want. I would just stay away from syn3, that stuff makes your motor sound like its going to rattle apart.

 

as a (auto) mechanic I recommend conventional also, if you change your oil in the specified interval, there is no difference and the dino is cheaper.

not to mention syn is thinner and seems to find the smaller areas to leak out of that dino will not. He probably gets tired of fixing the smaller leaks that syn tends to find. Also, if you don't change over to syn early enough, you will burn quite a bit more.

 

I am also amsoil dealer Jaronb. I use syn in all my vehicles, including my HD. Never had any leak problems, even in my 97 power stroke. What ever your comfortable with I guess?

 

i 100% agree with MXER, syn is thinner and finds its way out, guys i run with have done the conv-syn change only to find they need to add more syn oil to the bike b/c they are either using it or leaking it then they switched back to conv oil and badda bing no more oil going bye bye...to me run the heavier conv oil...i run the hell out of my bikes and run conv oil and have no issues....if you are worried about oil/motor temps get an oil cooler...enough said.

 

To be honest with the oil change intervals conventional oil is ok but if your one of those people that push the limits on everything then go with the sysnthetic for your own piece of mind.
Granted if you were in a bind you could go twice the interval with the syn.
I like to run all out and not worry.

 

There was a test with 74 new NYC cabs that went into service and used Mobil 1 for seven years. At the end of the seven years data showed that there was not one penny saved in longevity or repairs over conventional oil.

All oil is engineered and current oil is not the same as even ten years ago. Has no one noticed the continual changes in the API ratings?

Oil has friction modifiers that eliminate any friction difference in syn oil.

Typically a HD engine can go 100K before top end work with either type oil.

The posters that suggest not going with syn is not keeping up with the times have not keep up with the changes in oil themselves.

 

+1 these motors , primaries and transmissions get very hot. I use the best fluids I can afford. I want my bike to last as long as possible. MIght not have the cash to rebuild the motor in 15 years.