08 Nightster. I'd like to improve them slightly, no need for drop-ins or anything. I'd just like to know if the stock setup uses any sort of spacer in them, and if I can add or replace it with a longer spacer, and how long.

I would also like to swap the fork oil with Mobil-1 ATF. Don't try to talk me out of it, I've been using it in everything for 10 years with great success. MUST I remove the forks to dump it all out, or can I simply run an oil extractor line down there and get the majority of it?

I have the service manual, but not handy. Is there a provided oil level that is measured from the top down or only in cc's? Thanks!

 

While I'm not intimately familiar with an 08 Nightster, first of all, there isn't any way to measure the oil in the forks. Start by draining them completely. Use a half liter soda bottle to see what comes out. You need to compress the forks a few times to get all of the oil out. You say you have a manual but claim you aren't handy. This may be a job for a dealer. To drain and refill you are going to have to disassemble the forks from the top. Recompressing and reassembling them later is the tricky part. You want to improve your front end, but what constitutes improvement? Simply swapping out stock oil for Screamin Eagle super heavy race oil always made a very noticible difference to me, without fooling with springs and spacers. Most dealers don't stock the really super heavy stuff-you need to order it. I don't know the viscosity of ATF fluid but would almost guarantee it's less than a racing fork oil. As far as spacers and lengths-those aren't the type of things H-D puts in the manual-you are going to have to pull it apart and measure. What does the manual show if you look at the assy diagram?

 

I think he meant his manual is not handy. As in not in his immediate vicinity.

 

I recently had my forks rebuild by a specialist and he explained that a good reason for removing the forks to drain them is that muck accumulates at the bottom and doesn't come out any other way. The bonus is that normally the oil doesn't need changing very often. That is a long way of saying that it really is best to remove the forks, in any event it doesn't take long to do.

One of the problems with my Sporty's forks is the springs are too soft. If you extend them fully, with the front wheel off the ground, then compress them fully (easier with the springs out) you can measure total travel. When you sit on the bike the forks should sag no more than 1/3rd of the total travel.

So you can try fitting spacers under the top nuts and pre-load the springs enough to adjust sag to the correct value. I read somewhere that thick-walled plastic water tube is suitable, as long as it is cut with a proper pipe cutter (to ensure the ends are square).

 

I happen to have my manual handy, to drain the fork oil you remove the drain screw and washer at the bottom of the fork slider tube and compress the forks repeatedly till the oil is all out. To refill remove the upper cap and fill, a 883N and a 1200N hold 13.6 oz per fork tube.

As far as adding a spacer to eliminate the "sag" and give you more travel, I do not see why not. Just make sure you have some "sag" or free travel because you dont want your forks topped out all the time.

Other alternative is to buy springs.

 

On my N, I tried to insert a PVC spacer and washer (as small as 1/2 inch).
I personally did not have the strength (or special tool) to compress the spring w/ spacer and get the cap on. I do have the special tool - fork cap socket.

Going to heavier oil. You probably know this slows down compression and rebound...last this this suspension needs IMHO.

I did add 1/2 inch or so (as I recall) of extra oil to each tube which helped preload. Been two years no seal leak. I posted here on this modification at the time.

Best bet....new springs.

 

I just got a set of Ricor intiminators for the sporty. I am yet to put them in, but one day soon. I run them in my softail too and they make such a difference that I almsot could not believe it. Check them out here.
http://store.ricorshocks.com/category_s/62.htm


Drew

 

Sorry guys, I came here to delete my post as I finally made time to dig into the service manual this eve. I might try some spacers made of PVC. I did mean that my manual wasn't handy and I didn't see being able to dig through it anytime soon. To top it off it drives me nuts to not have the info at my finger tips all day long...lol. It's awesome that they can be drained from the bottom. I also know the crap that sits down there...at least in dirtbikes. I always flood em out with mineral spirits too and seen some pretty nasty stuff. Mobil-1 ATF is about 12.5 IIRC, only it's much more stable at high temp, but does get "thicker" in cold temps. Cheaper too.

 

****...for $300, I'd prob. just put toward new forks. HAHA

 

Same concept as the Ohlins 30 mm Cartridge System. I think I'd prefer these.

Can you supply the Ohlins units?