Fork oil

getting ready to put a fork brace on manual got me though well. thinking on se oil. should i use the exact amount per the manual, little or more or less. any advice

1st off, you don't want the SE fork oil - makes the front end way too stiff. H-D doesn't put the weight on the bottles but if I remember right it's SAE 30 while the regular is 15 weight - might even be 10. Bel-Ray does label their fork oil & you can get it @ nearly any bike dealership - other than H-D.

They make a 15, 20 & 30, but nobody makes a 25 that I know of. However some folks have mixed 20 & 30 1/2 & 1/2 to make their own 25, but that still makes the front end pretty darn stiff. Bel-Ray 20 will stiffen it up over stock, but that's probably all the farther you want to go.

Then to the amount, use exactly what the manual says & note the difference between "wet" & "dry" refill. In other words, if you take the forks completely apart & clean out every single drop, you'll put a bit more back in.

I haven't tried changing the fork oil on the Road King yet. I hope it is easier than the shovel head where it takes 3 men and a boy to compress the springs and then if you don't use silicone along with the new gaskets it is apt to leak like a sieve. No manual I ever read ever mentioned that. I had to learn that lesson the hard way. Then you have to fashion a funnel with a hose and a rubber cork with a hole in it and pump the front of the bike to make the oil go in, exact measurements are next to impossible. What a PITA! AL

i'm loooking to make it a litlle softer. whet from a stock hertitage wheel/tire to a 90/90 tire on a 21" wheel shaving about 18ibs off. going to just put oil back in so i'll go with a little less. i'm thinking a few mm less of 15 wt. does that sound about right?

thats what i was thinking too

belray also has 7 wt. but there 15 wt is nearly 11.00 liter, whereas hd has the standard wt for 5.00 /qt. is bel-ray that much better?

What exactly is fork oil? I wonder if hydraulic oil wouldn't work as well. Back when I was still workin' I took apart rebuilt hydraulic units that opened the gates of dams and was amazed at how hydraulic oil that had been left in those units for like 40 years was still clean and retained it's viscosity. AL

thats a good question

No, it's just easier to get (@ least for me) & the weight is on the bottle so you know what you're getting.

Fork oil is hydralic oil. Oh, there are some different formulations & additives, but yes, you could use hydraulic oil if you knew what weight it was. I know that some guys use automatic transmission fluid 'cause it's cheaper & you can get it so many places. But I don't know what the weight of ATF is - I'm thinking it's SAE 10 & that would be too light for my applications.

The Hydraulic Power Units undoubtedly had good filtration on them. Whenever the cylinders extend or retract opening, closing, or throteling the gates "new oil" is put into them. The oil in forks is "captive" (never changes) and will get dirty as contaminents can get past the wippers and seals.

If those cylinders were on St Joe Dam or some other dam on the Columbia River, our company built the control panels and power units.

It's been awhile so I don't remember the manufacturer but they were in Co. Pueblo Dam. We disassembled and rebuilt 4 units, quite an interesting job since some of the original parts were no longer available. AL

Interesting to meet a fellow Hydraulic guy!. I've been in the business since 1964 but am about ready to hang it up.

Yeah that was very interesting work but the hydraulic units were just a part of it we also replaced all the gate seals and had to replace one bottom sill which was made out of bronze alloy, it had to be custom made and sand blasted and repainted everything. Then there was electrical work. Al

the stuff in there was dirty as crap and thin as water with a greenish tint. so i put in some atm as a flush plus sort of get a reference point on what wt i want. assuming atm is 10 wt i'd do well with around 15 wt i think.

The viscosity of the fluid used appears to be a matter of personal preference.

I put straight 30W in my sportster with a few teaspoons of engine seal renewer to temporarily stop or slow a leak on the top seal on the right fork. (it actually worked well until the warmer weather hit last week. (90+ deg. F)

I love the way it handles, so when I get the seals replaced this week, 30W is going back in.

It most assuredly is & depends on many factors. 2-up on a BT on the interstate; solo on a Sportster on the backroads; stop-n-go city traffic; the size of the rider; if they cruise or push it a bit, etc. There is no "one size fits all" fork oil.