Removing Stiction from GL1000 Front Forks

GL1000 forks are notorious for stiction…especially if you use inferior, aftermarket fork seals. A bigger problem: careless re-assembly of front end components that can introduce additional stiction. The typical scenario is putting some “bind” into the forks by the manner in which the front axle is secured on the left side. This often happens after front tire work by sloppy mechanics. The GL1000 is very sensitive to this detail!

Here’s how to remedy. Keep in mind that the sequence and order of this procedure is very critical:

1. Start with the bike on a level concrete floor on the centerstand. Put a small floor jack under the front of the engine (with a very thin board to protect the engine). Jack up the bike just enough so that the weight is off the front tire. Warning: jacking beyond the point that the rear tire contacts the ground will lever the bike off the centerstand and cause a nasty spill.

2. For extra safety, run 2 tie-down straps down from the ceiling to the handlebars.

3. Loosen all of the following in this order but do not remove:

• Left side, front axle cap pinch nuts (left as viewed by the rider). There are 4 of these. Make sure you’ve loosened these 4 nuts enough so that pressure is off the retainer and the left fork lower (“slider”) is free to “float” relative to the axle. Test to make sure the slider can move side-to-side relative to the axle.

• All 6 of the bolts that secure the fender

• Top fork stanchion Allen bolts (secure the fork tubes to the upper triple clamp).

• Fork caps (just loosen slightly)

• Lower fork stanchion attach bolts (secure the fork tubes to the lower triple clamp).

4. Next, remove the fork caps to relieve the pressure from the fork springs.

5. Carefully lower the front of the bike with the jack until the fork is fully compressed. Be sure you have enough slack in the safety tie-downs to allow full compression. As the front end is lowered, carefully observe the action of the brake hoses and speedo cable to make sure they are not put into jeopardy by this extreme compression.

6. Tap the lower and upper triple clamps (stanchions) in several spots with a soft mallet.

7. Carefully tighten all of the fasteners in the following order. Very important: be sure the fork tubes are at the same relative height inside the triple clamps. Normally, they should be flush with the top of the upper triple clamp.

• Lower triple clamp pinch bolts

• Top triple clamp pinch bolts

• Left side axle pinch nuts

• Fender attach bolts.

8. This is a good time to make sure your fork oil is at the correct level. With the fork fully compressed and the fork springs removed, I run 160mm of free air space above the oil. This is a more accurate level of filling the forks than the factory suggests in the manual. Their method is approximately 6 oz when you drain the forks… 6.8 oz when you do a complete overhaul.

9. Raise the bike and replace the front springs. Loosen the top triple clamp pinch bolts again to reinsert and tighten the fork caps. Re-tighten the top pinch bolts.

10. Critical: Make sure you have adequate clearance on either side of the left front brake rotor relative to the caliper hanger. Adjust the axle as necessary for adequate rotor clearance. If adjustment is necessary, make the smallest possible adjustment. There is a feeler gauge in the OEM toolkit for measuring this clearance.

11. Road test.

12. Make a careful mental note of the positioning of the left front axle attachment, make a mark or take a close-up picture for future reference.

Again, the sequence and order of this simple procedure is the key to getting results.

Other Fork Issues:

I generally use ordinary Dextron ATF in the front forks. I’ve experimented with specialty fork fluids, and have found them hardly worth the bother. But, going to a lighter viscosity fork oil (like BelRay 5W) will slightly improve stiction on some GL1000s.

Front Fork Fluid Capacity:

OEM Method:

• When merely draining and replacing fluid: put 5.8 – 6.1 oz in each fork tube (170 – 183 cc)

• When rebuilding (completely dry internals) use 6.6 – 6.9 oz in each fork tube (195 -205 cc)

Randakk Method:

• With the forks off the bikefully compressed and the fork springs removed, I run 160mm of free air space above the oil.  Note that getting full compression is not possible with the wheel/fender installed on the bike.

Using “extra” fork fluid to “improve” dampening won’t help handling, but it will put extra stress on your fork seals.

Use Honda’s method (above) if you have any doubt about my method. Here’s why from a customer report:

“Thank you for your response. I happen to have a spare fork and measured 26.1 cm from the top of the stantion to the top of the slider when fully compressed. I then tried to fully compress the forks on my bike with the front wheel installed and the measurement was a bit over 30cm. I should have better heeded your warning and filled the forks when they were off the bike. Since I don’t want to pull the forks off again now, I guess I’ll drain the fluid and measure according to Honda’s procedure.”

Denis Mori

Critical: Polish the upper fork tubes carefully (the entire portion that travels through the seals) to remove any nicks and burrs. Imperfections will drastically shorten seal like. I use crocus cloth lubricated with WD-40. Wash with warm soapy water to remove any grit from the polishing process. Dry thoroughly. Keep the fork tubes clean at all times. Dried residue from dead insects will shorten seal life. Consider fork gaitors or guards if you are a high mileage rider.

The front forks on GL1000s are a weak link in the design. The tubes are undersized for the task and the damping is primitive. There’s no real adjustment capabilities. Plus, the slider bushings are a non-replaceable design.

Having said that, here’s some additional advice to make them bit more tolerable: Shocking Revelations

Comments

  1. john barker says:

    should the air dimension of 160mm be 260mm.
    have removed each fork from bike, drained oil, removed
    springs and collapsed fork to min. length, before re-filling
    with 175cc of fresh oil.

    • john barker says:

      additional info :-
      with 175cc of oil in each fork the air dimension is 285mm,
      to reduce this dim. to 160mm have to add a further
      85cc of oil. (total 260cc in each fork).
      is there a problem doing this?

  2. Greg Matson says:

    I was rereading your excerpts on your method of filling the oil. By free air space, do you mean from the oil to the top of the open fork or must you decrease for the space the fork cap takes up?

    Thanks for sharing all your info.

    gm

  3. Ken Ratcliff says:

    OK, I’m making an assumption here from your instructions.
    1. When I pull the top caps am I to pull my springs? I note you say to put them back in but the instructions don’t say remove. I’m new to MCs and these are the first tubes I’ve ever touched. BTW, I will be rebuilding my tubes with new seals, dust seals and progressive springs.
    2. I assume that the top triple tree while loose, will still hold the top of tube while I lower the bike with the jack?
    3. Since I don’t have overhead lifting capability can I just have another person hold the handle bars?

    Thanks for you help.

    I really like your technical blog.

    Merry Christmas,

    Ken Ratcliff

    • Answers to your questions:

      1. Re-read my step #8

      2. Yes.

      3. No. A human helper is not sufficient. You need actual overhead support as described for safety and effectiveness of the procedure.

      Hope this helps.

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