Author Topic: Progressive Springs installation ( ST1100 ) **  (Read 9858 times)

Offline KoTAOW

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Progressive Springs installation ( ST1100 ) **
« on: December 09, 2007, 02:17:46 PM »
by Hal Rumenapp (with photos and notes from Warchild)

What I discovered is that it is relatively simple to change the springs (with the exception of that damn cartridge!) especially if you own a floor jack. I had great concerns of dropping the bike if the springs were removed, but found it quite easy to support with the adjustable floor jack. Contrary to some of the advice I received this job was done with the bike on the center stand for the entire procedure. The process is a one man operation (except for that cartridge!) FWIW here it is:

1. First support the weight of the front end by jacking up the engine (be sure to use a piece of wood between the jack and the bottom of the engine to avoid damage to the case).

2. Loosen the pinch bolts on the triple tree using an allen wrench:

...and use 17mm allen wrench for the fork cap...

...and using a big-ass pipe adds some serious leverage....

and finally remove the left fork cap. (It is under pressure, but will only come up about two inches if the weight is off the front wheel).

3. Remove the stock spacer, washer, and spring being careful to wipe the old fork oil off the components and not drip it all over the place. You do not need to keep the stock spacer. Instead, you need to cut a new shorter one from a piece of 1" schedule 40 PVC pipe. This new one needs to be exactly 3.25".

4. Now loosen the right fork cap. This cap will not come off like the left side because it is screwed onto the fork damper rod inside the fork. To expose the cap and locking nut below it, you need to lower the entire bike down onto the front suspension. Do this very slowly and you will see the right spring slowly rise out of the fork. You can go ahead and lower the bike till it bottoms out on the forks. Keep the floor jack in place to steady the bike!

5. To remove the right fork cap, simply unscrew it while holding the lock nut below with a 14mm wrench.

At this point it is advisable to consider designing a tool to help in the removal and replacement of the spring locking collar. I basically used a metal rod at least 12" long threaded on one end with the same metric threads as the fork damper. Screw an extra nut onto the end of this rod (half the depth of the nut) and tape it in place. Now screw the other half of the nut(with rod attached!) to the end of the fork damper rod.

Editor's note: In this photo, you see my variation of this special tool, which is nothing more than a threaded bolt (same size threads as the metric theads on the fork damper rod. A silver-colored metric nut is threaded onto both the bolt and the damper rod end, and the entire assembly is held "up" by a strip of spare wire!
- Warchild

Next, if you have a companion near by, push down on the spring (it may take two hands!) until the spring seat stopper is loose and have the other person remove the stopper. The washer, spacer, another washer, and the spring can now be lifted free. Discard the spacer and one washer as you will not need them again.

6. Next, drain the fork oil by loosening the nut at the bottom of the fork tube using a 10mm wrench. (Only the early models have the drain bolt near the bottom of the forks. Later models need to have the forks removed and turned upside down to drian the fork oil.)

When it stops dripping, replace the nut and tighten. Be sure not to lose the small copper sealing washer!

7. Now add fresh fork oil (10 Weight is what most upgrade to from stock 7wt.) read John O's reply below before following these instructions! In order to measure the correct amount of oil to add to each fork, you must again create your own tool. Accurately measure a stick, rod , or whatever you have that can be inserted into the fork tube 5.5 " from one end. I suggest something long you can keep hold of so you don't accidently drop it into the fork tube! (5.5") is the distance from the top of the tube that the oil level should come up to. Pour some oil in and then place your measuring stick into the tube up to the pre-measured line. Pull it out, and if it is still dry, add some more oil(just a little at a time!). If you are careful and don't overfill, you can gradually raise the oil to the proper level. If you do happen to overfill, use something like an ol d turkey baster to remove the excess oil. Note: the left fork tube holds more oil than the right one.

8. Once the oil is in, you can insert the springs(tightly coiled side up as specified in the Progressive instructions)! This is contrary to the Honda maintenance manual instructions that say tight coils go down! If your homemade tool, still attached to the end of the fork damper, is long enough it should be sticking up just above the right fork spring.

9. Now for the hardest part! The spring will be sticking about two inches above the lock nut it needs to be locked under (after pulling the fork damper rod up as far as it will go). Be sure to put one of the washers on top of the spring. Now with a friend's help, one of you push down on the spring while the other pulls up on the rod. When the spring is compressed enough and the washer is below the locking nut, slide in the spring seat stopper. The locking nut is supposed to be 10.5mm(slightly less than a 1/2 inch) below the end of the fork damper rod to leave room for the fork cap to screw onto. (You might have to use a couple of pieces of scrap metal lodged between the coils of the spring to get enough grip to push the spring down)

10. Once the stopper is in place remove your homemade tool and screw the fork cap onto the right fork. Tighten the lock nut up against it. Now raise the bike till the front wheel is off the ground . Slowly screw the right fork cap into the fork tube being careful not to strip the threads.

11. The left fork tube can now be assembled. Be sure to put a flat washer on top of the fork spring, followed by the piece of PVC pipe you cut earlier. This side will require a little compression on the spring as you try to thread the fork cap into the tube. Go slowly and do not strip these threads either!

12. From here it is a simple matter of tightening the fork caps, and then the upper pinch bolts with the allen wrench. Remove the floor jack and GO RIDE!

« Last Edit: January 13, 2013, 01:50:36 PM by Tom Melnik »

Offline KoTAOW

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Re: ST1100 Progressive Springs installation
« Reply #1 on: December 09, 2007, 02:19:44 PM »

this fork oil level figure is just wrong.  Careful reading of the Progressive Suspension instructions reveals this 5.5" figure is the minimum volume of air above the fork oil that they recommend for bikes WITHOUT spec'd fork oil levels.  ST1100s all HAVE a spec'd fork oil level for each fork.  Use the Honda specs, not PS's generic figure.  Check the Front Suspension section of Chapter 1 (General Information) in your Honda Service Manual.

My 91 SSMST calls for a full 7.5" of air above the right fork's oil level.  Reducing that by 2" by adding a whole 2 more inches of oil than called for is just asking for blown fork seals, not to mention will result in one helluva stiff/harsh ride.

I'll add a good tip for this procedure from my friend Alan Hunt: to help reduce the odds that you'll cross-thread the very fine threads of the fork caps, do this:

- before reinstalling the fork springs, dry-fit the fork caps and make a mark anywhere on the side of the fork tube, and a corresponding spot on the side edge of the fork cap, with a Sharpie when you find the point at which the threads just begin to engage.  Then when trying to screw the caps back in while pushing down against the now installed fork springs, you've got a visual point of reference for where to initially position the caps before turning them to get the threads started correctly/safely.

That's all for now.  I'd like to put this erroneous fork oil level thing to bed for good.

Regards, John OoSTerhuis STOC 1058