Got my 1974 XLCH running fine; have flushed the lubrication system multiple times with a 5/30 oil in very cool weather; short rides. Now ready for the "permanent" oil. The motor has less than 10000 miles on it and I see NO signs of smoke at all.
Back in the 70's I ran Castrol GTX 20/50 in my BSA's, my 440 6 Pac, my 426 HEMI, my 340, and during my brief affair with a 409 dual quad. All ran well under a wide variety of temperatures and driving conditions. I planned to use GTX 20/50 in my Ironhead, as it is the only purely dino oil available locally. My HD tech buddy is, predictably, saying ONLY use HD360...what's the prevailing opinion BETWEEN THESE TWO OILS here. NO other brand of 20/50 dino oil is available locally...so those are my choices. Period.

 

Doesn't matter, dealers choice. What have you got against synthetics?

 

I run Brad PennGrade 60 WT in my vintage bikes, you want the extra Zinc. VR1 is also good. Brad Penn is impossible to find locally, I get it from JEGGS, Amazon or sometimes eBay. Not cheap but good stuff.

In a pinch, and if you can find it, HD 60wt will work.

 

Hey, I think that Valvoline VR1 racing oil has the extra zinc, too. Their website says double the zinc. I used to run that in my '67 MG Midget A-Series engine for that reason, and it comes in 20W/50 if you like that weight. Just a thought...

 

I'd run straight 50wt or 60wt in an Ironhead. They tend to run hot.

 

Sounds good. I believe VR1 comes in 60W, too. Almost positive the PO of my '51 FL gave me a few quarts when I bought it from him.

 

Get the VR1 in a 60 wt at the cheapest internet price and buy it by the case.

carl

 

Well; I kinda contradicted myself…
Makes sense now that if my local store has GTX, they should be able to get GP…all mineral WITH zinc; perfect for motor, trans and clutch.
GTX wasn’t the best choice and I resort to online or out of town only as a last resort. One case of 20/50 GP in hand; ready to ride!

 

Gotta shake my head here. The old bikes call from the factory for straight 50,60 or 70 wt petroleum oil, there's multiple reasons for it. Put syn in an old one it's start bleeding oil not long after, synthetic will weep from everywhere, nature of that product it wants OUT. All the fanbois of the multi wt 20/50 in the old ones, don't care what the spec sheets and the hype says, at running temps the oil is physically thinner viscously wise that straight wt's. There's been multiple side by side testing done on video to back that. Run 20/50 in an pre evo machine it is going clatter more that straight 50 or 60 would.

**** isn't rocket science people and this topics been beat more than 14 yr olds dick who just found his dad's Hustlers stash.

 

I have only ever run strait weight oil in my Ironheads usually 50 wt.