In my opinion the best and least expensive thing you can do to the Nighthawk 750 is add new Progressive fork springs. The bike handles so much better that it will put a grin on your face the first time you ride after this suspension upgrade. The best thing about this upgrade though is that the entire project can be done for around $100.
After receiving my new springs from BikeBandit.com, I head over to my local Honda dealership and picked up three bottles of Pro Honda Suspension Fluid SS-8. I probably could have gotten by with only two bottles but I’m the kind of person that would rather have too much than not enough.
I first removed the front wheel and unbolted the brake caliper and fender from the forks.
The hardest part of this whole project was breaking the fork tube end caps loose. These are supposed to torque at 17 foot pounds. After three attempts at breaking them loose with a 12 inch cheater pipe over a 3/8 drive ratchet they finally came loose with a loud snap. I didn’t remove the caps at this point I only broke them loose.
Use a standard flat screwdriver to pry off the rubber cap on top of each fork tube to access the end caps.
Loosen the pinch bolts that hold the forks in place then gently slide the tubes off the bike. Be careful not to scratch them.
One at a time remove each fork tube end cap and pour the contents into a large baking pan or what ever you have available that is clean and will hold everything.
.Be sure to pump the fork tube up and down a few times then collapsed it completely and pour what little fluid is left in the tube into the pan.
I was amazed at how easy this was to do and how few parts were inside.
According to the paper work that came with the Progressive spring kit I need to cut a spacer for each fork 3.870” in length. The spacer is just some PVC pipe that is supplied with the kit.
I loaded the spacers one at a time into the chuck on my lathe and cut them to finish size. This step is not necessary but I had the equipment and wanted the ends to be perfectly square.
I then poured new fluid into the fork tubes and pumped each one a few times to get it circulating, one took about 15oz and the other took a little less for some reason. With the tube completely collapsed I lowered a steel rule down into each tube about 5.500” inches. I adjusted the fluid level until the end of the steel rule had just barley touched the fluid at the 5.500” inch mark. The factory specifications require that the fluid level be at the 5.400” mark but Progressive recommends a maximum of 5.500” because the new springs will displace more fluid.
The only real odd thing that I ran into on this project was when I dumped the fluid from the second fork into the pan. This was the brake caliper fork tube. The fluid was real dark gray, almost black (it also smelled bad). I have never seen any signs of this fork leaking but it didn’t appear to have as much fluid in it as the other one did. We found this to be strange but everything else seems to be fine with the fork. I bought some extra fluid so I used some of this to flush the fork tube out several times before refilling the tube to spec.
Notice the dark fluid in the pan as it mixes with the lighter fluid from the first fork we did.
I dropped the new spring into each fork with the tight wound end pointing down and placed a washer on top of the spring which was also provided in the kit. Then I added the new PVC spacers we made and tightened everything back up. I had to be careful at this point to not cross thread the end caps when I reassembled everything. The torque specification for the end cap is 17 foot pounds.
I mounted the tubes on the bike and re-installed the front wheel, caliper, and fender to complete the project.
NOTE: The new springs are definitely much stiffer after the first inch or two of travel than the stock springs were. With the stock springs I could hold the front brake, rock the bike from front to back real hard and the forks would bottom out. I could not get the new Progressive springs to bottom out using this same technique.
Here is a link to where you can buy the Progressive fork springs used in this project: