I have a 1978 FLH shovelhead what weight oil should I use the manual says 70. I am running a oil cooler and a external oil filter.

thanks

 

always used 20w50 76 also set up with oil cooler, remote filter horse shoe tank

 

I switched to 20W50 on both my shovels around 20 years ago and I am happy. A lot of guys will tell you the spec is for 60W or 70W but I've put mega miles on my '79 and have had no problems, plus it starts so nice on cold days. Been thinking about Amsoil for a while now but still a bit scared on that one without blocking off the primary. I'm still wary about Amsoil and my clutch plates.

 

In S. Florida I've always used 60 or 70wt year round. Just don't make the mistake I made and ride it to the Smokeys in November. The next morning the oil looked like a turd hanging from the dipstick . Took forever to get it warm enough to start the bike.

 

I have solid lifters in mine and run 20-50 for many years. Don't know if 20-50 will work with hydraulics though.

 

i have a 76 shovel kick only, I run 50 wt in the winter and 70wt in the summer,
so far so good!