Bad Brad, a martial arts Sifu, and the previous owner of the San Pedro Kick Boxing School recently bought a ’98 King from the Billet King. He still owns his 1964 Panhead, for 40 years. The Road King was clean as a whistle, and had an air system to lower the rear shocks, but the front end bottomed out and we looked at options with Progressive Suspension.
Brad wanted the keep a lowered look and took the bike to Bennett’s Performance for a service and to evaluate the handling. As it turned out the systems inside the stock 41mm glide legs were original, with the exception of two air lines running to the fork tube caps. Plus the preload was minimal, so the Bennett’s tech Gabe Vidrio went to work investigating the malady, while I reached out to David Zemla at Progressive Suspension.
After some long discussions between Brad and Eric Bennett, we decided to install a stock length Progressive spring system. “They don’t handle well lowered,” Eric said.
I’m still trying to understand this Progressive system for lowering glide front ends. According to the Progressive literature with a lowering system in place the front end will not compress anymore than stock. The main spring is the same length as stock, and the only change is the addition of a 1-inch spring under the dampening rod on the opposite side of the main spring.
Here’s the info from the Progressive Suspension installation instructions regarding lowering:
The installation of a fork lowering kit does not affect the compressed length of the fork. However, we have found that some motorcycles may not have adequate clearance between the fender, fairing and/or accessories.
Therefore, we recommend that this be checked and if there is not adequate clearance, the interfering parts be removed or modified to eliminate the clearance situation.
After installation of new top out springs onto the damper rod, we recommend that the forks be installed on the motorcycle complete with
wheel/fender, but without the main springs and completely bottomed out.
This is done to check clearance between the
fender and fairing/crash-bar/accessories, etc.
Remove and disassemble forks (including removal of damper rod) according to steps outlined in an authorized service manual for your particular model and year Harley Davidson
To achieve a one inch (1″) lowered height, leave the stock top out spring on the damper rod and install one Progressive Suspension top out spring on the damper rod with the stock top out spring.
To achieve a two inch (2″) lowered height, leave the stock top out spring on the damper rod and install two Progressive Suspension top out springs on the damper rod with the stock top out spring.
Let’s Get Started:
We went with the stock system, and I followed Gabe as he rebuilt the legs with the Progressive Suspension components, new seals, and fluids. Here are the Progressive instructions with comments from me and Gabe.
Read all the instructions carefully before installing this kit on your motorcycle. Use your factory authorized manual as a reference while installing this kit.
Support and lift the motorcycle securely so the front wheel is off the ground. The balance point is toward the front of the engine.
Remove forks according to instructions contained in your factory authorized shop manual. It’s always handy to have a shop manual handy, and you might want to disconnect the battery.
For maximum performance we highly recommend that the forks be disassembled, thoroughly cleaned, and inspected. When installing
Changing the volume or viscosity of the oil is not recommended and could cause damage and/or loss of control.
The Progressive Suspension Monotube cartridge fork kit is a direct replacement of your stock internal fork components. In our case we just replaced the springs with Progressive units.
However the procedure on the left fork (stock cartridge) for the 02-05 FLHT/FLT varies
from the damper rod type forks. If installing this kit on one of these models, note the variance.
After removing both forks, start with one of the forks and remove the fork cap, then remove the fork spring.
CAUTION The fork cap is under spring pressure depending on the pre-load and care must be taken as it is removed to avoid injury! Keep downward pressure on the cap as you unscrew the final threads, this will minimize the spring “jump” that will occur as soon as the cap is fully un-threaded.
Drain the fork oil, and then with the fork completely compressed remove the damper rod & top-out spring by removing the bolt in the bottom of the fork. Keep the fork assembly fully compressed at this point to keep bottoming cup properly located.
Put the stock damper spring onto the stock cartridge.
Put a drop of red thread-locking agent on the bolt that came out of the bottom of the fork and reinstall it, tightening it the bolt to the factory recommended specification of 11-18 ft. lbs
Repeat the process on the other fork and proceed to “Both Forks”section of instructions – unless you’re installing this kit on a 02-05 FLHT/FLT, then proceed to next step for left fork.
Reinstall the supplied bottoming cup (with the cup facing up) into the outer fork slider and carefully insert the inner fork tube back into the
outer slider.
Maintain the orientation of the bottoming cup while doing this – the bottoming cup must seat in the outer slider as the stock cup did. Once seated, keep the assembly compressed to maintain it’s position during assembly.
Per you factory authorized manual reinstall the fork seal using a proper JIMS fork seal driver tool, and then reinstall the fork seal retaining clip.
Install the supplied Progressive Suspension top-out spring as shown onto the stock monotube assembly, with the supplied washer and then Gabe reviewed the instructions for cutting and setting the preload. Progressive recommended 1.5-inch preload spacer which he cut, but was unhappy with. The original preload spacer was 5/8-inch and the forks bottomed out. He cut it down to 1 1/8 inch, compressed the front end and was pleased with the results.
Pour 5 ounces of 10 wt. fluid in each fork, pausing to stroke the assembly to get the fluid into the outer fork slider
Failure to do this will cause the required amount of fluid to overflow.This fluid is just to lubricate moving parts and has no effect on the actual damping
action of the sealed Monotube cartridge fork insert.
Once the proper amount of fluid is in the fork assembly, slide the inner
fork tube up and install the supplied fork cap. Torque the cap the factory recommended specification of 50-60 ft. lbs. Gabe used a very special JIMS socket for this operation.
Reinstall the forks and all other components on the motorcycle per your factory authorized manual being sure to double check all fasteners for proper torque per said manual
Technical info: Our technical staff will assist you if you have any problems or questions. Call (714) 523-8700 from 8 am to 4 PM Pacific time.
“To compliment your suspension,” said David Zemla the doctor of Progressive Suspension, “we recommend installing a pair of our 412 Series Gas Shocks, 430 shocks, 440 Series IAS Shocks, or the Progressive 970 shocks. Check them out.”
There you have it. We disconnected the air system from his front end, and David Zemla recommended to plug the caps. Brad’s King is back on the road.
TECH FLASH: JIMS VACUUM FED FORK FILLING TOOL–
“This Year’s Time Saver”
Changing the fork fluid on models with fairings can be intimidating and take hours. This patent pending tool will eliminate the need to remove the fairings on all touring bikes to change the fork oil; it’s like magic. With this tool it should take about 30 minutes to perform the service compared to 2.2 hours without it.
Drain the fork, and simply insert the tapered fitting into the drain hole and create a vacuum using a standard Mityvac hand pump. Once you reach approximately 23 lbs. of vacuum pressure rotate the valve and instantly the vacuum will draw the pre-measured amount of fork fluid into the fork tube.
Use on all common damper tube type fork assemblies, this tool is not for use on motorcycles using cartridge type forks or inverted fork assemblies. This tool is designed for use in conjunction with a Mityvac tool No. 741, which is available separately.
For more information contact us at sales@jimsusa.com, visit www.jimsusa.com, or call 805-482-6913.
SOURCES
Bennett’s Performance
JIM’S MACHINE
Progressive Suspension
