HarleyTechTalk

My bike is a 2014 limited minus the tour pack, I weigh 210lbs and ride solo, I installed the race tech gold valve with the yellow spring with 2 turns of preload, I also drilled 2 more 7/64ths bleed holes in it and 4 more 5/16th holes in the damper. I use maxima 15w fork oil set at 150mm, with 30mm of pre load on the 1.20kg fork spring. I have approximately 44 mm of sag. It rides and handles fairly good but I feel It could be better . All replies and suggestions are appreciated Thanks

44mm sounds like a bit too much sag to me.
Try adding a bit more pre-load.

I'm in the middle of  tweaking my front suspension. changing fork springs and pre-load.
I think I have more pre-load on the Race Tech Emulator and I do use 15W fork oil.

Plan A is it goes back together tomorrow...

Your using a set-up that is a good base for 41mm forks,  49mm application may be different.

What does the fork feel like?  Ride quality, small stuff, big hits?   What needs to be improved?  Is the fork better in warm or cold temps?

Increasing the preload will change ride height and available travel but ride quality will be basically the same other than scenarios that bottom the fork.  It does sound like you could use 5mm to 10mm more preload.  However much the preload is changed will change the ride height/laden SAG the same amount.

Race tech switched their suggested fork spring preload to "actual" installed preload some time back.  That is the actual preload on the spring once the fork is completely assembled and fully extended.  The difference between actual/installed and the old way of doing a static measurement prior to installing the fork cap is the amount the top-out spring compresses once the cap is installed... easily measured by the amount the fork length increases.  Use a maker or tape on the fork tube at the leg and measure change once the cap is installed.  Subtract that measurement from a static/stack-up preload measurement done prior to installing cap.   -Rick

https://racetech.com/page/title/Emulator%20Tuning%20Guide

My bike has the 49mm front end. I set it up the same set up I had on my 2012 limited with 41mm forks, I noticed that race tech instructions for my 49 mm forks are 35mm preload where I have 30 mm measured from the top of the upper tube to  the cap o ring seal. It  feels like its hitting to hard on the bigger bumps. Also race tech suggested 165 mm oil height and I have 150mm 

RT calls for 35mm actual/installed.  I would add 10mm next time you have it apart.  If your laden SAG measurement is accurate 12mm would put you right at 1.25" laden SAG.

I believe RT oil level is 150mm on touring models and 165mm on Dyna's for 49mm forks.

Is the fork bottoming?

No the fork is not bottoming, I will add 10mm to the preload . THANKS to all the replies and settings recommendations I was wandering about the oil level, now I know
. I will update after adding 10mm pre load  Thanks Again

I wouldn't be in a hurry to go back in just to add spring preload.  Unless the fork is bottoming adding preload isn't going to improve anything other than increasing available travel to handle big bumps and increasing ride height for ground clearance & lean angle.

If you could rig a tattletale of some kind and measure travel on different surfaces/bump sizes and ride the bike enough to really now what is/isn't happening.  Not saying this is true in your case but lots of times riders claim their fork isn't bottoming because the hydraulic stop mutes the feel.

You are right 04, I should have said I don't think it is bottoming, My dad always told me listen and learn Thanks for all your help

AFAICT the 49mm tubes only have about 100mm travel total including the hydraulic stop but not any compression on the rebound spring.  At least that is the way the M8s are set up.  I'd shoot for 25mm sag but like to setup the forks on the high side.

Quote from: Admiral Akbar on November 16, 2020, 06:08:50 PM
AFAICT the 49mm tubes only have about 100mm travel total including the hydraulic stop but not any compression on the rebound spring.  At least that is the way the M8s are set up.  I'd shoot for 25mm sag but like to setup the forks on the high side.

How is there no compression of the rebound/top-out spring when assembled? 

Not sure how much fork travel these have.  The tubes are a different part number than your M8 RK FWIW.

1" laden SAG would be minimum but it's not ideal to "cheat" by setting laden SAG at 1" unless the rider is aggressive and needs the ride height/lean angle or extra travel but totally understand why you would on these heavy, short travel, limited lean angle bikes...if I owned a touring bike I might set it at 1".  Little on the short side for down travel to track road surface but then these things don't carry a light front wheel off corners.

The spring is there. It's how the measurement was taken. No spring compression spring in the fork, extend the tube til it touches the top out spring. Measure. Push the tube all the way in. Measure.  Total travel include the bottoming dtop but not the top out spring is about 100. You pick up a little from top out spring install but give up some due to the bottom out system.

M8 bagger tubes, springs and damping rods are different than later TC baggers due to the new bending shim damping but I suspect the travel is the same. I'm thinking all 49mm tubes had all their travel cut to 100mm but can't say for sure.

   Good measurement for total fork travel,  your figuring that the hydraulic stop takes a little travel away,  enough to make up for what the rebound spring compresses under the fork spring preload pressure once assembled. 

Rebound/top-out spring compression is needed to know actual/installed fork spring preload...RT suggest 35mm "actual" on 49mm touring models...should be approx. 40mm measured static before assembly.

If the 49mm touring models only have 4" of travel that is just what Harley needed to do to a heavy, already short travel, soft sprung bike.   

UPDATE on my 14 limited front fork set up at the recommendation of several very knowledgeable people on this board and after talking to Race Tech  I made the following changes I went from 30mm preload on springs to 40mm preload, changed setting on gold valve spring from 2 turns of preload to 1 1/2 , at  Race Techs  suggestion went from 15w fork oil to 20w oil and set the oil level from 150mm to 165 mm. I went from 41mm sag to 27mm sag.  I am very very satisfied with how my bike handles and rides. Thanks again for every ones input

Quote from: topcat3815 on December 04, 2020, 05:10:13 AM
UPDATE on my 14 limited front fork set up at the recommendation of several very knowledgeable people on this board and after talking to Race Tech  I made the following changes I went from 30mm preload on springs to 40mm preload, changed setting on gold valve spring from 2 turns of preload to 1 1/2 , at  Race Techs  suggestion went from 15w fork oil to 20w oil and set the oil level from 150mm to 165 mm. I went from 41mm sag to 27mm sag.  I am very very satisfied with how my bike handles and rides. Thanks again for every ones input

The original settings used were for 41mm forks which a lot of guys have used...not 49mm.

Forks must have been bottoming as a couple others suggested. 
The Admiral mentioned possible short travel on 49mm forks which lessens available travel. 
Did you check the total fork travel when you had springs out making the changes?
- A tattletale would show how much travel you are using.  Knowing the total travel of the fork and how much you are using helps a lot.

The changes made both softened and firmed the fork.

Changing fork spring preload:
  Its hard to measure laden SAG accurately given fork stiction, so measurements can vary some. 
  The 10mm change (30mm to 40mm) in static uninstalled fork spring preload made a 10mm change in ride
  height and available travel when riding. 

Changing/decreasing the emulator spring preload:
  Decreases the pressure needed to open the valve initially,  decreases low speed compression damping and
  makes a linear change/decrease in compression damping for any given fork movement speed/velocity where
  the valve is open. So a general decrease in compression damping.

Increasing fork oil viscosity:
  Increases compression and rebound damping across the board.  Normally chosen to get the desired rebound
  damping as rebound damping is not adjustable with emulators and still controlled by the damper rod...same as
  a stock fork.

Reducing fork oil level:
  Increases the air volume in the fork making the air spring less progressive.  This reduces the spring rate of the
  fork in the bottom of the stroke,  approx. last 1/3 of travel...reducing bottoming resistance.

Net result of changes:
  -More available travel.  Helps with bottoming.
  -Increased rebound damping.
  -Increased compression damping,  reducing the emulator spring preload 1/2 turn did not erase the 5wt
   increase in oil viscosity.
  -Less progressive overall fork spring rate decreasing bottoming resistance a little but not enough to cancel out the increase from fork spring preload increase and increased compression damping.

The changes that are somewhat counter to each other as to compression damping and spring rate deep in to travel.

Increasing travel and compression damping will help the fork not to bottom as often or as hard.  Reducing the oil level took same of that away.  If a fork can handle the work load without bottoming to much it's better to have a less progressive fork.  Most suspension tuners try for a set-up that is linear not progressive...they don't want an increase in spring rate that could reduce grip/traction deep in the stroke.  On heavy,  short travel,  relatively soft sprung cruisers I feel ride quality is important and am willing to make the fork more progressive than desired to reduce bottoming.  Another trade off on cruisers is laden SAG,  setting preload/ride height at the minimal sufficient laden SAG gives more available travel and clearance/lean angle. 

This post facilitated by coronavirus 19.  -Rick

More changes on 14 limited forks, changed fluid from bel ray 20w to bel ray 15w and changed fluid height from 165mm to 150mm everything is the same. Seemed to handle bumps better, Im leaving it alone now