I have a 2003 Road King. I have always had the dealer service it, but now I have tricked out my garage, got a lift and ready to start servicing it myself.

In West Texas we are 85 at 7:30- am and 105 at 5:30 in the afternoon this time of year.

What oil should I use in the engine, primary and trans?

 

20w50 syn in crank, primary oil in the primary and 85w140 or 85w90 syn gear oil in tranny...By the way welcome to the site.

 

Thanks for the input.

What about Lucas 75/140 in the trans during the summer, still to thick??

 

75/140 lucas??

 

AMSOIL 20w-50 in all 3 holes

 

For max heat breakdown resistance; for sure in the crankcase full synthetic 20W-50

 

That is a fine product for the tranny, I use Walmart syn 75w140

 

I use redline shockproof in tranny, 20/50 hd syn in primary and 20/50 Royal purple in crankcase

 

Normally I run Mobil 1 synthetic 15W50 in the engine, but during the 'dog days' of summer I sometime run RedLine 20W60 in the engine. For those that don't know, RedLine is one of the best fully synthetic Group 5 fluids available.

For what it's worth, been in the mid to high 90's around here (97 today), and that's pretty common here in the lower midwest at this time of year.

And before someone comments that a 60 weight oil is 'too heavy' for a TC engine you might be surprised that even Harley recommends a 60 weight oil when the temperatures are 80 F or higher...

Anyway, I run the below in all my bikes when it gets up in the mid 90's or higher. Other guys I ride with just stay with the Mobil 1 15W50 year around in their engines and their bikes run as good, and are as trouble free as mine.