What oil weight should I run in my 79 ironhead sporty? Synthetic or petroleum based? I live in the Texas panhandle...

 

I couldn't tell you for sure but I know some guys that run straight 60w in their Ironheads.

 

thanks!

 

Thats what I used to run.

 

Synthetic oils tend to be light multigrades to suit modern engines. Unless your engine has been rebuilt recently and the builder recommends synthetic, I should stick with petroleum based. If you don't have one find yourself a Harley workshop manual for your bike.

 

My '70-78 manual has medium-heavy {75W} for temps above 40, special light {58W} below 40, and regular heavy {105W} above 90 degrees F. Should be able to find a viscosity close to those numbers (haven't seen "58W" lately). Ditto on sticking to the petrol-based, IMHO, unless the engine has been reworked using "modern day" bearings; may be too slick to allow bearings to spin so they develope flat spots.

 

I agree, avoid synthetic. Post some pics, would love to see it.