One of the projects on my list for this Spring is to change the fork springs on my '07 1200 Custom. I've decided to go with the Progressive fork kit. Now, I have to decide on fork oil. I suppose that I could go with HD standard fork oil, or I could get something else. I'm currently leaning towards something else.

So, tell me about the fork oil(s) you have used and the reason for your choice.

 

Just did mine. Honestly I don't believe one could tell the difference in brand. I used 10w and paid $6.50 at my local M/C repair shop. Just enough to do both forks. Anything had to be better than that stinky black stuff that came out, this obsession has to stop somewhere!

 

If you are going with a stiffer overall spring rate, you're going to want to increase the weight of your fork oil proportionally. Otherwise you can end up with not enough damping and you'll have a wild fork action.

 

For me just changing the oil per specs (something I should do more often) make a tremendous difference.

 

I got halfway through swapping my stock fork springs out for the Progressive kit, and lost track of time; the local indy shop was closed, only place open was the HD dealer.... so I went with stock weight HD branded fork oil, filled to the level that Progressive has in the installation guide. Huge improvement over stock, for what they cost, it's one of the better "bang for the buck" upgrades you can do. My opinion anyway.

 

Roni, I'm about 75 miles south of you here in Colonial Beach. I installed the Progressive fork springs and used 7w Belray. I had used Belray in my MAICO Motocrossers and figured, why not? It was great choice. The forks and the 13.5" Progressive 440s work in perfect harmony.

 

I used Harley Screamin' Eagle Performance Fork Oil Heavy on my bike and Type E Harley fork oil in the OL's bike, both with Progressive's springs. My bike also has a longer spacer to introduce more preload. I'm about 205#, the OL is substantially lighter. Having riden both, I prefer more preload and heavier oil. My riding style may be considered spirited, but not hard core.

 

Progressive 440's? Wow. You spare no expense on your bike. If The Missus found out that I spent $500 on a pair of shocks, she would deep fat fry my gonads then serve them to me for dinner.

Thanks for the advice folks. As a heavier guy (220#), it looks like I'm going with a heavier fork oil.

 

Would Napa heavy duty Hydraulic oil work ? I have gallons of this stuff in the shop...

 

Thanks Roni, at 203 lbs. I used the included spacers at their full 3" length. The front rides about .75" higher than stock but no topping out. Maybe I avoided the gonad roast by buying these Ameritex bags for 96 bucks and free shipping. I referred to the stock shocks as immoveable objects accompanied by spine jarring. Its nice to have the rear wheel stay firmly planted in bumpy turns with the 440s. Zero squat on take off is a + too.