Installing a Progressive Suspension
  and Lowering the ACE
Installing a Progressive Suspension and Lowering the ACE
  Lately, I have been doing a lot of long distance groups rides with my SCRC chapter in the Ottawa region and one of the biggest annoyances I had with my bike was the way my suspension was handling on the rough roads and twisties. When you start hitting the good size potholes and doing a lot of hard braking turns, you really notice the ACE's stock suspension diving a lot and bottoming out. My fender has several good sized scuff marks from my forkbag impacting it! So I decided to do something about that and I got a whole new suspension from Progressive Suspension. If all you want to do is improve the front end, then you can go with just the new fork springs. For under a $100, you're bike will be greatly improved! If you want to go the complete route, then you can get new rear shocks as well, but they are a little more pricey. The 412's I got are about $185 USD on most Ebay stores (plus shipping of course). I wanted my shocks fast, so I bought them locally at a shop in Ottawa and they came to $305 Canadian. A little bit more, but I had them the next day.

  Also, I figured since I had already decided to upgrade the suspension, that i would lower the bike at the same time as well. The ACE has always been pretty comfortable to me, but I am still a little short in the legs and I figured a 1" drop in the bike would make it much more easy to handle and also enhance the looks, without taking a serious hit in the clearances. So, to lower the rear of the bike, I had only to choose a smaller rear shock then the stock size of 12.5". I went with the 11.5" 412's. Lowering the front takes a little more work, but is still fairly simple... you have to cut down the spacer in the fork the amount you want to lower the front. And since I firmly believe that the Honda engineers knew what they were doing when they designed the ACE, I decided to lower the front by the same amount as the rear, to keep the geometry the same, front to back.
  1. Progressive Suspension 412 Series Rear Shocks - P/N 412-4201C (for mine, I went with 11.5", which is 1 inch lower then stock);
  2. Progressive Suspension Fork Springs - P/N 11-1126;
  3. Wrenches and Sockets. 22mm Socket for the fork cap. 12 + 13mm are the only other two sizes you need.
  4. Bike Lift. You could do this with just a floor jack and jacking the front or back up as needed, but the lift is ideal;
  5. Fork Oil - Stock Honda oil is SS-8, which is equivalent to 10WT oils of other brands;
  6. Hack Saw and file or sandpaper. For cutting down the stock metal spacer. Or you can fabricate a new spacer from PVC tubing of the same outside diameter;
  7. 20cc Large Syring and 1/8" clear plastic tubing - or a Turkey Baster if you don't have access to that. For adjusting the fork oil level;
  8. Measuring Tape



Step 1:

Lift the bike until the front wheel is completely off the ground.
Click to Enlarge Click to Enlarge
Step 2:

  The "by the book" procedure for replacing the fork springs in the Honda manual is very long and complex.  It involves removing the front wheel and brake.  Removing the handlebars.  Removing the upper bridge (triple tree) and the chrome fork covers and then remove the forks from the lower bridge.  There was no way I wanted to do this, so I took a few shortcuts.  Basically, all you need to do is remove the fork caps and then pull everything out of the forks.  If you have the stock handlebars and risers on your bike, then you will need to move the handlebars a bit to give you space to remove and install the springs.  Remove the 12mm nuts from the riser bolts below the upper bridge (see pic above).  Then cover the gas tank with a protective cloth and gently pull the handlebars back and lay them on the tank to give you access.
Step 3:

  With the front wheel completely off the ground, remove the fork caps of both forks with a 22mm socket.  You may need someone to help you here as the caps can be seized on a bit and you don't want to risk pulling the bike off the lift.  Also, it might be a good idea to tape the soft aluminum fork caps to prevent them from being scratched.   The caps have a slight pre-load even when fully extended, so be prepared for them to "pop" a bit at the end.  Once they are off, examine the O-Rings, clean them and put the caps aside in a soft, clean spot.  Replace the O-Rings if they have any nicks or cuts.  Using a clean rag to keep the oil from dripping on the bike, pull out the metal spacers next and lay them aside.  Now lower the bike slowly until the forks are completely compressed.  The springs are still several inches down in the tubes, so you have to make something that can fish them out.  I just bent a piece of wire and hooked one of the coils.  Pull the springs out slowly, using a rag again to prevent oil from going everywhere.  Also, as the top of the spring gets near the opening, make sure to grab the flat washer that is there.  You will need these again.
Click to Enlarge   Here is the old stock spring and spacer beside the new progressive spring.  It's easy to see why progressives give you such a nicer ride!!
Step 4:

Once you have the springs and spacers out, then we can check/adjust the fork oil level.  This has to be done with the forks fully compressed and the springs/spacers removed.
  First you need something to check the level.... I used a small 6" piece of wood dowel as a dipstick.  I them marked the level I needed on the dipstick using the tape measure.  The problem is... the new springs displace a lot more fluid then the stock ones, so the levels in the shop manual won't work.  Progressive gives you a sheet of instructions and they recommend a level of no higher then 5.5" (from top of fork to oil).  Also, at this point, you can either try and remove as much of the old oil as possible and then replace it with new oil or just adjust the oil as needed.  My oil still looked good, so I just used the turkey baster and adjusted it until I had 5.5" showing on the dipstick.  The forks are on an angle, so don't make the level exact.  Try to get it so that the highest (at the rear sie of the fork) is 5.5" or a little more even and check it several times.  Once you are satisfied that the oil level is correct and, more importantly, equal on both forks, then we can cut the spacers.
Click to Enlarge Step 5:

  We need to cut down the stock spacer, since the new springs are a lot longer then stock.  Also, at this time, I am taking an extra inch off to lower my front.  Using the chart that Progressive gives you, you need to make a 5" spacer for these new springs. (4" for my lowered dimension).  I used a hacksaw to cut the stock spacers down and then I used a file and sandpaper to make sure they were level and all the edges were smooth and clean.  That's very important, so that the spacers don't damage the insides of the fork legs.
Step 6:

  Finally it's time to put it all back together again. Raise the bike again, until the wheels are off the ground. I had a bit of a problem here in that my forks wouldn't extend for me. Seems they got a bit bound up while sitting fully compressed. So I had to pull on the front wheel and tap it a bit before they finally fell down and extended.

  Now place the new springs in the fork tubes. It doesn't really matter which way you place them, but I have always believed that conventional wisdom calls for the tight coils to be on the bottom.

  Now place the flat washers on top of the springs.

  Now place the spacers in next and then screw on the fork caps and torque them to 16 lb.ft. Remember, it's a soft aluminum cap with a rubber seal, not a steel axle nut!

  Now reposition the handlebars and put the washers and nuts back on the riser bolts and torque them to 20 lb.ft.

  Lower the bike and while sitting on it and holding the front brake engaged, pump the front end up and down several times and make sure it's working ok and not binding at all.
Click to Enlarge Step 7: Rear Shocks

Changing the rear shocks is a piece of cake and only took me 20 mins to do both! The new units from Progressive come completely assembled and ready to bolt on.


  First, raise the bike on the lift until the rear wheel is just touch the ground, but no real weight on it.

  Now remove the bolts and washers from the top and bottom of both shocks and then pull the shocks off.

  The new 412's come ready to bolt on as they are, but if you do, for some reason, need different sized bushings, the kit comes with several to choose from.

  If you are using stock sized shocks (12.5") then you can just go ahead and put them on at this time. However, I choose 11.5" shocks, so I had to lower the bike a bit until the upper and lower pins lined up. then I installed the new shocks. This is where the bike lift really shines, as it would be pretty difficult doing this with just a trolley jack or some other rear wheel jack. There are special shock compressors, but they are expensive and why would you buy them just to install the shocks once?

  Once the shocks are on, then just re-install the bolts and washers and torque them to 20 lb.ft.

  Now lower the bike and that's it! All done. The shocks come with a spanner wrench that you can use to adjust the preload, just like the stock shocks. So play around with the settings and pick the one that suits your tastes.
Final Results:

  I am very happy with the results. The day after I did this mod, I did a 450km group ride to Kingston.  Going there, we took a lot of back roads, while coming back, I used the 401 and 416 highways.  Overall, the feeling of the bike is much better now.  Even two-up, the ride was firm and I never bottomed out the front end once.  It's suprising too, because, before, my fork bag was a good three inches above the fender and it would bottom out whever I hit a decent sized pot hole. And now, the fork bag sits less then 2" above the fender and it never bottomed out in 5 hours of riding!

  The biggest change you notice is that you no longer dive when hitting the front brakes hard.  Instead, when you yank the front brake, the nose nudges down an inch or so then stays.  It's made me much more confident to use the front brakes when doing twisties.  Also, it seems that the bike is a lot more nimble, which is probably do to the lower center of gravity.  And of course... with it being an inch lower, I find it much easier to handle the bike while just sitting still or in a parking lot.

  Last, but not least, I really like the look of the new rear shocks and the lower stance.  Here are a couple of pictures of my ACE on the day after I did this mod...
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