Good stuff,

Don't remember if I asked but do you know what the shim stack is on the compression valve inside the fork. I think we discussed this at one time. The RT valves I run are a little stiff as dropping to 0.8 kg/mm springs helped on mine.

I'm still running the stock kelsey-hayes front brakes with Z pads, SS brake line and sunstar rotors (HD SE) .. IMO They work fine. 2 fingers without a lot of pressure can lock them up but they feel pretty predictable. Same brakes are OK of an road king and marginal on an Electra Glide. I'm sure you are saving some weight tho.

What tires are you running? I pretty much run a 180/55-18 Bridgestone Excedra in the back and 110/80-19 Bridgestone T30 in the front.

 

Good to hear, T! Always love reading your post-mod ride reports.

 

I'm not completely sure how to answer your shim stack question, but here's an exploded view from the Ohlins manual:



The Ohlins piston/valve kit is FPK 109, intended for a Triumph Daytona 675. I believe the FPK series are pretty much all the same universal kits for 20mm cartridges, but the shims are setup differently for different bikes. Howard recommended this one. Here are a pair prior to installation (stacked on the shipping bases), compression on the left:



Here's a closeup of the compression valve, installed on the Showa base:



...and the rebound piston, installed on the Showa rod:



I could be totally wrong about this, it's purely based on anecdotal stuff I've read (some from you), but my impression is that the Ohlins valves flow more oil than the RT units, allowing the adjusters to provide better tuning as well as the use of a heavier spring. Or I could be way off base!

Here's how the fork is setup now:

Total Sag: 41 or 42 millimeters
Springs: Traxxion Dynamics .9 kg/mm
Oil: Bel-Ray 5 weight
Rebound Setting: 9 clicks from full clockwise (factory recommendation was 8)
Compression Setting: 11 clicks from full clockwise (factory recommendation was 10)

Before installing the BrakeTech rotors, I was also running OEM Sunstar semi-floating disks (well, not OEM on my bike, but on some... Mine were solid disks in the front originally). I did weigh the old and new rotors... The 13" BrakeTechs are over a pound lighter (each) than the 11.5" Sunstars! For pads, I'm using Ferodo Sintergrip, as that's what BrakeTech recommended.




I'm running stock 13 spoke rims, 150/80/16 on the back, 100/90/19 up front. Avon Cobras (not the new Cobra Chromes). Based on your experience with an 18" rim in the back, it's something I would consider if I ever get around to different wheels...

Thanks Chris! Lots of muddling around, but it's coming along...

 

The pictures were very helpful. This picture shows the shim stack as far as I can tell. I do wonder what this thickness of the shims is tho.




While you say the Ohlins flows more, as far as I can tell, the RT valve can flow way more. If you look at the Ohlins compression passage, it is way smaller than the RT passage.



Gold valve has larger passages. It almost looks symmetrical for compression passage and flow through. The result is that the RT valve needs more shims.



The recommended shim stack based on my weight was cH35 which has 5 0.15mm x17mm shims and a 7 shim series to control flow. The Ohlins only has one large shim and a 4 shim series to cover the ports. While the force on the Ohlins shim is likely less due to the port being smaller, the RT shim stack has way more shims.

I do think that RT recommended too many shims but I will say, I can plow through a heavy step type bump and the forks will take it without bottoming. The forks do feel stiff tho.

I totally agree with you that getting the correct compression fork action correct depends on how the compression damping is set up and the spring rate used. I've messed with this when modifying RT emulators for bagger shocks. You can increase compression damping to adjust for lighter springs or even decrease spring rate for heavy compression damping. It works both ways.

Thanks again for the pics and info.

 

Instead of saying that "I'm not sure how to answer your shim stack question," I should've said "I don't have the data to answer your shim stack question."

I had thought about measuring shims, but I was nervous I would get something wrong reassembling the stacks if I took them off the locating rod. However, after reading some more Ohlins literature online, I have deciphered their part number/measurement convention. Looking at the part numbers in the diagram, the beginning "014" seems irrelevant to the dimensions (as far as I can tell). The next two digits (immediately preceding the dash) are the shim thickness in mm tenths. The two digits after the dash are the outside diameter in millimeters. For example:

01425-12 = .25mm thickness, 12mm OD
01425-14 = .25mm thickness, 14mm OD
Etc...

Interesting to see your RT pictures. Definitely two different approaches between the two brands! Thanks for the info!

 

Well you might have been able to measure the thickness of the bigger diameter spacer without pulling it apart but 0.25mm seems reasonable since the main spacer on the RT is 0.15mm. Stating 2 0.15mm shims together is likely lighter than one 0.25mm shim but I suspect that 3 0.15mm shims might be a little heavier. (Just guessing).

It's really the thickness in hundredths..

A good book to read about this stuff is Paul Thede suspension bible.

This is a good discussion.

 

One thing note about settings. While these guys are all about fine tuning, they bring up differences in ride aggressiveness, rider weight, tires used etc. It's always been my belief that if one person has what he thinks are the best settings for himself, they may not be best for someone else. I've copied other persons settings for forks that included spring weights, RT emulator adjustments, fork oil selection and found that due to differences in other parts of the bike, they didn't work. Fortunately for us, we are tuning for general riding conditions and not trying to get every last bit of performance out of the bike.

 

F86, I have done a lot of research on the fxdx and trying to decide if it is worth looking for a low mileage 02 fxdx or a 14-17 low rider? I currently ride a 16 wide glide that i am trying to sell. Want something that I can go on longer rides with but still rip around corners when i want. Love the look of the fxdx especially when they are all done up with right bars, fairing, etc.
How do you like your fxdx? Would you recommend it or have you had a lot of problems/repairs because it is a 17 year old bike? I know that I would need to make sure motor mounts, and fork seals are good. I also understand that the cam chain tensioner was upgraded in 01/02.
Sorry if this is the wrong place to post but I came across this thread when searching for threads on fxdx.

Thanks,
Mike

 

Hi Mike,

First answer: I LOVE MY FXDX!

...but there are things you should consider. Maybe surprisingly, in my experience (with older and newer bikes), reliability isn't really a significant factor in a decision like yours, at least not for me. My bike is 19 years old, but it's been extremely reliable. The history of the bike is a much bigger factor than it's age. I've owned this bike for four or five years (can't remember offhand), but I'm only the second owner. It's also not a high-mileage bike (not that I'm scared of mileage if the bike has been well cared for). It's never left me stuck anywhere (well, once. But it was totally my fault and was easily corrected. I didn't properly tighten an adjustable pushrod once, and ten miles from home it got really short!). This bike does pretty much everything for me that I could expect of a single motorcycle. It fits me really well, it has the attitude and personality of an American hot rod/street machine, it can hold a passenger comfortably, it can hold detachable saddlebags which allow me to run errands and shop with it if I want... It's as competent on quick twisty roads as I could expect from a 19 year old 600lb bike (my favorite kind of riding), it runs without a problem on a week long trip with lots of gear, and I've "made it my own" as best I can to reflect my personality and taste. I've also known and seen many people with brand new bikes have annoying reliability issues and glitches, so again, I personally see no real difference in that respect (it's also fair to note that I've replaced lots of things along the way, but never because anything "failed," more because I preferred a different option. But maybe something would've failed had I not replaced it). I'm not saying an older bike needs no more maintenance than a newer bike, they usually do. I'm just saying that newer bikes have issues too.

But there are things to consider... First, think about some of the "personality" differences between an older FXDX and a newer Low Rider. The first one that comes to my mind: Carb versus fuel injection. I like the combo of a Twin Cam and a carb. To me, they suit each other. But fuel injection can be way easier to live with sometimes, when it comes to different temperatures, altitude, fuel quality, riding style, etc. And when it comes to engine mods, a carb may need physical rejetting, whereas FI may just need a tune uploaded. There's also the physical dimensions of the bike. It's almost hard to pinpoint where and why this is, but if you park my bike next to a late made Low Rider the older bike is just smaller. I like that. You may not. The earlier Dynas seem lighter, more nimble, more tossable... That suits my riding style.

It's also important to take into account what you want to end up with (as much as you can up front). Are you planning on performing a lot of mods? Mostly aesthetic stuff or performance stuff? More about power or more about handling? Or do you like to keep things pretty original? Factor in which bike is closer to what you want to start with, as that will save you time and money as you move forward. If you're planning a lot of mods, look at availability of desired parts for each model. Some vendors no longer focus on pre '06 Dynas for certain parts. Would you do work yourself or work with a shop? Huge price difference between the two!

I'll add that if I was in the market for a newer Dyna, it would most likely be a Low Rider in the year range you mentioned. You start with a 49mm dual disk front end, the styling is really attractive, and you avoid the "Low Rider S price premium."

Just one more thought on the FXDX: If you've read this thread, you know I put a lot of work into suspension. I have zero regrets about it... I learned a TON and it's clearly an upgrade for my riding style. But it's not necessary. The FXDX rear shocks are excellent, and the fork is very competent. But I doubt I would be able to deal with a "conventional Harley" 39mm fork... That would be gone right away!

Good luck deciding, and most importantly: Be really honest with yourself about which makes the most sense for YOU to live with! Don't pay attention to what seems "cooler" or any such thing!

-Tarik

 

This member decided to do something different by working on and improving his Harley. Most here enthusiasm ends with asking "What new color HD is going to come out with next year". Tarik is not that kind of guy. He took advanced components than made it fit after figuring it out how to make it work, and not being scared to do so. He made the bike ride and handle better than it ever had at the factory. He used parts that the factory never thought of to improve his bike for him. He asked questions of other members and got them involved and gave them a purpose to think. He did this without the use of big wheels and sparklers in the spokes. Sanitary V/S clown'ery. IMO this is the hart of what a biker is.... Thanks for the ride.