How To - Front Suspension Service (no more "drunken horse")
Parts Needed, Tools Needed, Before You Begin, A Little Bakground, Why Was That Important?, Dive In, Look Carefully, Can I just Add Nylons?, Inspect Rear Mounts, What Do I Do Now?, Take a Break, Final Assembly, Care and Feeding
Topic: So your wetbike has been handling like a "drunken horse" lately and you want to diagnose it and fix it properly.
Expertise Required: Intermediate
Estimated Time: Couple of hours tops
- Full set of Nylons (8 total)
- Full set of Sleeves (8 total)
- New Nylok nuts (as needed)
- Metric wrench to take the bolts loose
- Small hammer to drive bushings in or out
- 4 inch angle grinder to grind sleeves flush
Before You Begin: There are lots of things that work in combination to make a "sloppy" front end. There's the nylon bushings, the stainless sleeves, the bolts and/or stud (depending on year model) and the steering pole itself. All of these can have minor or significant wear - but luckily everything is fixable.
So, the object of this tech article is to fix any-and-all things that'll tighten up the front end and let it have a long service life.
The old 50hp bikes had a steering tube that large bolts threaded directly into. Worked pretty good, but you gotta check those bolts occasionally. This generation also had a Bolt-n-Nut setup on the other end of the beams. You have to check these occasionally too.
The next generation had the steering tube drilled-through and used long bolts - a better design.
Then came the advent of the double-ended-stud through the steering tube. It also had NYLOCK nuts on both ends. Much better.
Somewhere in time, the rear connectins were changed-over to a double-ended stud as well. In addition, there was a sleeve that went in the middle to help prevent over-tightening. The best design so far. About this same time, the ski foot went from a 4-bolt to a 6-bolt design - and a noticeable bulge was added to the outside edge of the casting (both sides).
Since all of these designs have wear in different places, it's important to know what your are looking at. If possible it is best to upgrade to the latest-and-greatest design, but that' s lot of work on the older styles.
With that in mind, I'll walk you through some common ways to fix your steering.
a. How much gap is there between the H-beams and the steering tube?
b. When you move the ski side-to-side (while holding the steering tube with other hand) - can you see where the slack is. Look close - you should see wear/slack in the bushings, but you might also see lots of slop in the rear end of the H-Beam too. Remember these areas for later reference. If you see a lot of slop, plan on replacing the H-beams too.
Go ahead and pull the bolts/studs on the upper arm and let the ski fall away. Be aware that you might have to take screwdriver and get these things apart. The reason for that will be made clear in a few minutes.
Now, go ahead and drop the bottom bolts/stud so that the ski can now be removed and placed on a suitable workbench.
Look very closely at the steering tube for excessive wear. That is, look to see if the stainless bushings have been "working their way" into the aluminum. Hopefully not, but probably so.
If you wanna go cheap, just replace the nylons. Go ahead and buy another set too - they won't last more than a year. Why? If you look at the steel bushings that come out you'll see that they are crushed/deformed (usually on one end or the other). When you put these back in with new nylons, they just wear through quickly and you're back to the same sloppy front end.
ALWAYS REPLACE THE NYLONS AND STAINLESS BUSHINGS AS A SET - NO EXCEPTIONS
Inspect all 4 mount points looking for the same type of damage the steering tube might have (bushings working their way into the aluminum).
What Do I Do Now? If you have the old style (where the bolts thread into the steering tube and/or ski foot) then you can only do so much. It's not worth it to have the aluminum welded-up, so you have to use a workaround (outlined in the final assembly step). This workaround is THIN STAINLESS FENDER WASHERS. Take one of the Bolts and get some that just barely slide over the bolt's shoulder.
Note: If you have bolts that are fully threaded, go ahead and scrap them and get the kind with the proper shoulder on them. The fully-threaded ones don't make a good fit for the Stainless Bushings. You are trying to eliminate slop remember? Also, if your ski foot is drilled through, the fully-threaded bolts will eat into the aluminum. Bad.
If you have the newer stud-style setup, there's a couple of things you can do to bring it back to better-than-new condition. Here's the steps:
Step 1 - Go fish out those old, worn-out bushings you threw in the trash, or keep in your spares pile.
Step 2 - Take drill bit that's slightly smaller than the OD of the bushings and counterbore the holes in the steering tube. Drill to a depth of about 3/4 the length of the Stainless Bushing you are gonna insert.
Step 3 - Carefully pound-in a used steel bushing. Carefully - If it starts to squish too much, pull it out and go up one size on the drill and try again. Once it bottoms out, take a 4-inch grinder and grind it down almost flush. Measure the inside dimension of one of the H-Beams and make this ever-so-slightly-narrower.
Step 4 - After you get all 4 installed and ground down, take the drill and ream out the holes. Use a size that's barely bigger than the diameter of the stud. If you go too big, you'll be sloppy again.
Step 5 - Do the same procedure on the rear mounts (the ski foot).
The idea is that you want to tighten-up the hole to keep the stud from moving around. As a bonus, you now will have a Stainless-to-Stainless connection - NO MORE DIGGING INTO THE ALUMINUM.
Throw one of the studs in your pocket and run to the local hardware store (Lowes, Home Depot, Tru Value, etc). You want to look for some THIN STAINLESS FENDER WASHERS. These are your secret weapon. Grab about a dozen or so. You want to size them so that they just barely slide over the stud. OD should be about 3/4" I think.
Step 1 - Take a minute and apply a minute amount of waterproof grease on the nylons and Stainless Bushings. Why? Simple . . . it makes things more interesting when you're assembling things.
Step 2 - Install the rear bushings and sleeves in one of the H-Beams. Then slide the beam into the ski foot - lower holes. If older style, install a bolt on one side (without nut) then the other side. Check for side-to-side movement. If your foot is damaged on both sides, put at lease 1 THIN STAINLESS FENDER WASHER on each. Shim as necessary to eliminate play - but not so tight that it starts to bind. Tighten down the bolts and then install the upper H-Beam the same way.
If you have the newer style with the long stud and center sleeve - do the same procedure and shim if necessary.
At this point, you are ready to move from the workbench back to the bike.
Step 3 - Carry entire ski/foot assembly back over to wetbike and position carefully. It might help to lower the bike slightly at this point. Install the Bushings/Sleeves from the outside into the lower beam and do a trial fit - checking for clearance on each side. Shim if necessary and/or if you have the old style (threaded hole).
Step 4 -Continue on to the top beam and repeat the process. Keep in mind that for alignment purposes you might not have the same number of shims on each side as you did on the bottom beam. That's OK as long as the H-Beams are parallel and there is no binding when articulating through the full range of motion. Any misalignment binding will lead to premature wear.
Step 5 - Tightening the fasteners. Care should be taken here. You want to tighten the bolts, but not so tight that you crush the Stainless Bushings. If possible use NEW NYLOCK NUTS and you should be just fine.
Copyright 2011 Capt'n Obveeus