2020 FLHX - Front Fork questions; Fluid capacity, type, etc

[Wharfcreek]

I have a 'new-to-me' 2020 FLHX and I'm trying to prep it for an extended journey coming up mid June. I'll be on it for 2 to 3 weeks, probably about 4K miles. I've had the bike about 3 weeks and already done a cam, tuner, pipe, and added some upgraded rear shocks. I'm still unhappy with the front forks. They're just too stiff!

I'm thinking I want to try a fluid change, but I've been all over the web trying to find the fluid capacity for these forks, and best I can tell is it's 24 oz. If anyone can confirm that I'd really appreciate it. Also, I'm wondering what the 'stock' (or 'factory' fluid fill) is in terms of viscosity? Again, a web search seems to show 15W as being pretty likely. And again, if anyone can confirm that, I'd like to know. But, more to the point, if anyone has a recommendation short of replacing the springs or cartridges, that too would be appreciated. I'm thinking about going to ATF, which is about a 7.5W oil. I may even go with a 5W, but before I do anything I'd love to get some feedback here. Maybe not worh the effort? Maybe an alternative? Or.... maybe a good idea and do it?

Any feedback is appreciated. Many thanks, WC

 

[buck99rog]

According to the 21 service manual, 24oz is the capacity assuming that the forks were taken apart and all internal parts were cleaned. It calls for "type e" fork oil. What weight that is hasn't really been defined.

But with running a lighter weight oil the front end will feel like it's bouncing all over and the front end dive when braking will definitely be more noticeable.

 

[Wharfcreek]

Buck, so your advice is ‘not’ to go with the lighter weight oil? Kinda confusing when I’m not really sure where I’m starting from. Assuming ‘Type E’ is the factory fill, but Type E having an unknown value as related to SAE viscosity ( ie 10w, 5W, etc), I can just leave it alone, OR, take a swag at it and maybe start with some 10w and see what happens.

A friend who purchased some Ohlin rears said he talked to Ohlin, and while they said he’d be back to buy the front cartridges after he spent some time trying to ‘fix’ without them, he also said they recommended a 10 or even a 5W as a starting point.

I bought the Legend Revo-A and it’s a definite improvement. Just limited to the rear. The front really needs help too!!

 

[buck99rog]

Yes, that is what I'm saying. Not to run with light weight. It may be a softer ride with the lighter weights, but I would want the front end to feel as if it were planted to the road.