Have a 06 Road King and have been using dino oil since day one. Now have about 12k miles.At some point I want to switch over to syn 20w50.
I have heard that when switching from dino to syn, the syn oil can actually remove the sludge that is plugging up any leaks, mostly on high mile bikes.
What should the max mileage (or is there one) be to avoid leaking and any other issues when going to syn?

 

Switch and don't worry about it, you will be fine.

 

A simple aid might be adding 4oz of Seafoam to the engine oil and ride it a couple hundred miles before draining. A more expensive aid might be using an oil scavenger system to get out all the old oil. Or just get it nice/hot and drain...

 

Agree with Sefferdog

Synthetic and conventional oils are fully compatable. You can switch back and forth any time with no problem.

 

Thanks..

 

And what would that aid?

 

Just taking a stab at his intention here, but I think he is saying the seafoam will help scrub out the remnants of the dino before he switches to syn?

I wouldn't go to all that trouble personally. Just drain what is in there now, then fill with your oil of choice.

 

Yup, That's basically what I meant........

 

The only problems you would encounter would be with engines made pre-1994 or with more than 50,000 miles. Just drain & fill no issues. No need to scavenge. I have seen guys switch auto engines at 100,000 miles by doing a 50-50 dino-synthetic mix change for 2 oil change intervals and then go 100% synthetic with no issues. You could also do 2 oil fills with HD Syn3 which is reallly a hydro cracked mineral base oil and then switch to a synthetic if you are concerned.

 

112,000 on my 07 and no problems using either oil.......