I am sure this has probably been discussed before but heres my question, I recently bought a 98 Road King with an EVO with low miles. I run Synthetic in all 3 holes in my 05 twin cam, can I do the same in the EVO?

 

Sure you can. But be advised syn oil will clean up the engine and if you have any gasket voids that are currently plugged with sludge and not leaking, the syn oil will eventually clean off the sludge and you might spring a leak.

 

Now I will not get into an oil debate, I will only give you my experience with changing to synthetic on my 91 FLSTF. I was told that syn was the cats *** and I "needed" to change to it(by some oil expert not my shop), I had put a cam, heads, and a 2-1 exhaust on it, so I changed over about 2500 miles after the motor work and about a week after the oil change the bike smoked a little upon start up, I just blew it off thinking well I better watch this thing a little closer. Bike had less than 10k miles but the heads had been done so I was thinking if it continued it was the valve seals, either they went bad due to install or overrev. Well it got progressively worse and I took it back to the shop that did the motor work and he called me and said come on over and he would show me what the culprit was. Got there and the rings were stuck solid in the piston grooves. He asked me if I had made any changes to the bike like timing advance or jetting and I said no just changed the oil at 2500 and used syn, he honed the cylinders to fit new pistons and rings, put in conventional oil and gave the bike back to me saying don't put in syn oil again. I didn't and still don't use syn in my 2008 T/C due to my past negative experience.

 

On my 89 FLHTCU I have run syn oil in it for 70000k"s and have never had a oil problem with it. And on the 99 heritage I had run syn in it for 50000k"s. Never had any excess oil usage or leaks doing this. I always ran mobil 15-50 in both bikes. running amsoil in the 07 and quite happy with it.Just my

 

Stay with dino!

 

Just put mobile one 20/50 V twin in my 95 flstn so far so good but I'm keeping my ears open. I'm thinking of Castro 20/50 maybe the better choice but I believe in syn and thought I would give it a go.

 

Thanks for the feedback, sounds like there are pros and cons. Again thank you all for the input.

 

sure you can. worse case will be youll end up with a few, or many, oil leaks.