Seca 400 - Steering Bearings Refurb

[kirkn]

I did this project on my 1982 Seca 400, but it is applicable to all the models. This is just a refurbishment of sticky, grumbly, stiff stock steering bearings. This is not a conversion to tapered roller bearings.

To begin with, my bike's steering was stiff and notchy. You could feel a clear 'detent' right on center and was very stiff to turn either direction.

Most of the time, I've found that the bearing races and the balls themselves are NOT damaged, just stiff with ancient grease. If the races or balls are damaged, then refurbishment is not really an option.

In addition, I'm replacing these non-stock gauges and blinkers with stockers from a parts bike, and I'll be tidying up the cables/wire routing that seems to be all over the bar area from a previous owner.

Here's what I start with:

It took me about an hour to strip the whole front end apart. Unplug all the various plugs in the headlight shell and feed the shell off over all the various wires. Then, keep taking stuff off - gauges, headlight mount, switch assemblies, lever perches, master cylinder, horn, bar, etc.

Then, of course, the front wheel and fender. I just put the bike up on the centerstand and used a small scissor jack under the motor to keep the front end up off the ground.

 

[kirkn]

Ooops, I didn't get a picture of the old grease before I wiped it out, but it was aged, dirty and stiff.

Here's the top race with the old grease wiped out. There were no dents or notches in the race, so I'm good to go.

I soak the balls (19 from the top, 19 from the bottom) along with the upper seat in mineral spirits. Here's also a shot of the lower race before cleaning and the lower steering stem bearing seat.

Next, a shot of the lower bearing seat cleaned up. (I also stripped and will re-paint the lower triple clamp)

Nicely cleaned, ready to go:

 

[kirkn]

Once all the hardened old grease is cleaned outta there, and things are refurbished (paint or whatever), it's time to go back together.

I used ordinary wheel bearing grease and a small brush to load up the upper and lower races with grease. This holds all the balls nicely in place for reassembly. I fill the race with grease, then set the balls in the grease, then brush a layer of grease over top of the balls.

With that, it's easy to carefully insert the lower clamp / steering stem back into the steering head. You just be careful not to bang things around and dislodge the bearings. But, with all that grease, they're not really wanting to go anywhere anyway.

Once the stem is back in place, you've got to hold it there while you set the upper bearing seat (pre-greased) over top, then the dust cover, then the setting nut.

And that's really the "refurb" part. The rest is getting the bearings set right and the forks put back together right.

 

[kirkn]

So, the next few steps is just the steps I follow. I've learned over the years this gets the fork correct and gives the best chance for getting the bearings set correctly the first time. Your method may vary.

The manual says to tighten the ring nut to 18 ft-lbs, then back it off 1/4 turn. I didn't have a fitting for the ring nut to use a torque wrench, so I used a pair of channel-lock pliers and "estimated" 18 ft-lbs, then backed off 1/4 turn. That 18 ft-lbs makes the steering VERY tight, but the 1/4 turn back makes it nice.

The next step just calls for putting the top triple clamp on and tightening the stem nut to 30 ft-lbs. But, how do you know where to put it / how to align it with the fork tubes? This is how I do it:

I start with putting the upper triple clamp in place and just lightly snug the center bolt. Use a rubber mallet and tap it home at the center bolt location. This makes a positive seat against the ring nut.

Then, I put one fork leg in, position it flush (or just a hair above) the top triple clamp. Then, tighten the bottom triple clamp pinch bolt. No upper pinch bolts yet.

Then, I put in the other fork leg and position it identically to the first - flush (or just a hair above) the top triple clamp. Tighten the pinch bolt.

I'm using the lower triple clamp surface area to "square up" the fork legs to each other. The clamping area is about an inch long, and once they're pinched, you're not going to be tweaking the fork tubes out of line no matter what. At this point, the upper clamp is just lightly bolted to the steering stem.

Next, I re-seat the upper clamp with the mallet and THEN torque the steering bolt to 30 ft-lbs.

So, this is a bit of trial and error. When you torque the steering stem bolt, you're really drawing the stem upwards within the tiny bit of slop in the ring nut's threads. There's not much slop there, but enough. If you over-torque the stem bolt, or if the ring nut was a bit too snug, when you torque to 30 ft-lbs, the bearings will be too tight.

Damn - mine were just a smidgen too tight. I could feel a bit of grumbling in the bearings when moving the fork from side to side.

So, I loosened the stem bolt, loosened the ring nut about 1/12 of a turn (5 "minutes" pretending the nut was a 60-minute clock-face). Then, re-torqued to 30 ft-lbs.

That time, it came out perfect, as far as I could judge.

At this point, you've got the forks positioned correctly (same height, leg-to-leg, and no 'twist' or 'scissoring' between upper triple clamp and lower triple clamp).

Next comes the upper fork leg pinch bolts.

And you're done! Steering should be smooth and easy from side to side. No binding, no sticky, no grumbling.

The rest is just reassembly of the front end. Again, it took me about 2 hours to get mine all back together again - wheel, fender, brakes, gauges, headlight, etc.

Hope this helps.

Merry Christmas, and Happy New Year to everyone.

Kirk

 

[drewpy]

nice one Kirk, some good info in.

Merry Christmas to you to man

 

[xschris]

Nice write up I am sure this will help a lot of guys out. Merry x-mas

 

[lhaolpa]

I,also have an'82 Rj seca but all the headlight stuff,fairing,windshield,etc was all cracked,as was the speedo/tach. I got earlier model speedo/tach and headlight/ears,so it'll have a different look,but I kept the front fender,which I like a lot.I also have a tank from an '82 turbo seca 500,I think.It's a big blocky thing,but I think it'll be nice.Great write-up. lha

 

[HoughMade]

Nice write-up on the steering head bearings. It would b very useful to me...had I not already done this. Probably would have taken 1/2 the time with good instructions. In my case, I had to spend a bit of times on my hands and knees with a magnet to recover a few of the 38 bearings.

 

[lhaolpa]

I first removed the fork tubes,then wrapped a trash bag around the triples,then removed them and caught the balls in the bag.From there,it was easy cleaning up everything and repacking the bearings. lha