Back when my 74 XLCH was running (California) I used to put 60w in the bag and the primary. I remember some discussions about using different weight oil in the primary, usually a lighter oil. I know a lot of miles have been put on these bikes by a lot of people over the years and I am sure some good conclusions have been reached. Stock clutch by the way. What is everyone pouring into their Ironheads?

 

The old Ironheads have a valve between the primary-tranny and the crankcase. Therefore, whatever you use in one hole you oughtta be using in the other, 'cause there will be oil interchanging. That said, if you can use a multi-weight without any leak problems, I recommend a 20w-50 in both holes. By running the multi, you'll get much better protection at startup, where the straight 60 allows more wear.

 

How does the thinner viscosity affect oil pressure? Do the stock pump and pressure relief valve do the job?

 

It won't have any effect worth worrying about. The system is a low pressure-high volume and it'll do fine with the multi-vis.

 

Ok. Does this pertain to a 1970 XLCH? I need to change the oil in it. I added straight 50 w oil recently, and it is cold in the am in NM right now, and I could definitely feel a difference. Much harder to kick and get started in the colder am.
Would 20w- 50 be a good choice? The bike has 8700 miles on it.

Thanks, Steve

 

reno.......
I advise you to keep using the 50W. You want to use the same oil in the engine and clutch/transmission because of that slight oil mix through the valve poco was talking about.
I use 70W here in Houston TX in our hot summers and use 50W if the winter gets cold. Lately the HD dealership has been stocking 60W oil and so I have gone to that now that it is available. 60W is the recommended oil for an ironhead.
Since I am not an oil engineer I go with what the factory recommends using.
Out of the book, the recommendation for a 1970 XLCH is as follows:
Harley Davidson Grade 75........above 40 degrees F
Harley Davidson Grade 58........below 40 degrees F
Harley Davidson Grade 105......Severe oper. temps at high temperature
Those are the old Grade classifications Harley once used and are no longer relevent or made.
75 was like 60W
58 was like 50W
105 was like 70W (or like Bere Rabbit Syurp)
Yeah, in the cold winter 50W is some thick stuff. I have cranked on mine for a lot of winters now and it don't get easier to start up the old bike, but myself, I would not put 20-50W in my bike. After the engine starts and heats up to operating temp......I really do not think having thin oil in the tank is a good thing........pg

 

I have used 20W-50 on my -74 XLH and now in -78 XLCR, here never will be warm :-(
max last summer was 87ºF this morning there was 19ºF...
If it isn't leaking with 20W-50 I would use it... one of my friends uses 5W-40 synthetic (mobil 1) on his ironhead, without problems...
Here link study

 

I usually run an approximate 50/50 mixture of 60wt and 20w50. Makes it easier to start in cold weather and gives a little better protection at startup. I used to run 60 or 70wt in the summer and change to 20w50 for winter, but I was caught a few times by cold weatherwith molasses in the motor and couldn't start it. I now run the 50/50 mix year round.

 

Thanks for the replys all.[/align][/align]Thanks piniongear. I respect your opinion, as many others do in this forum, so I will stick to the 50w. I may place a heater by the bike before trying to start it in the future! [/align][/align]Kicked my tail yesterday trying to get it started at 8 am at 35'. Getting it flooded and me being 53 didn't help either. I had a meeting w/ a client in Taos, NM, soI was wanting to take the bike on a daytrip. The drive from where I live to there is through 2 mountain ranges, terrain like the moon in places, and the Rio Grande gourge and it was about a 260 milesrt. I did spot a Bald Eagle in the gourge yesterday. I had not seen one since leaving Northern MI a year ago. Oh well, another time.[/align][/align]Thanks for the insight all.[/align][/align]Steve
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reno......
Well, others here have used 20-50W and it sounds like it works for them, so it must be OK to use it. If the bikes are still running without any problems then you cannot argue with that.
Cranking up in the winter is not a lot of fun with an ironhead. Like you say, getting it flooded does not help things either. I usually kick mine through a few times with the key off just to get some fuel into the combustion chambers. The spark is not affected by the cold of course, but the inability to spin the engine over with the cold oil and fuel mixture in the chambers is the problem.
Man, I only wish I had to ride through two mountain ranges to get somewhere and be able to see an eagle along the way! I have been to NM and it is a beautiful place to live and ride.............pg