Headsteady bearings 75 MK3 850

Just asking.

Does anyone else have problems seating the bearings in the headsteady or is it just me. To get the old ones out I had to use a 16 lbs hammer. When I put the new ones in I had a .120 " gap between the spacer tube and the bearings and they would not seat any more. Cleaned up the ridges that was at the seat where the bearing stops , .030"high and .015" thick. The bearings seated finaly but just wondering was this just my bike or have others had this same problem getting the head steady bearing to seat and why such a tight of a fit?

Just asking.

Chuck W

ChuckW said:

Just asking.

Does anyone else have problems seating the bearings in the headsteady or is it just me. To get the old ones out I had to use a 16 lbs hammer. When I put the new ones in I had a .120 " gap between the spacer tube and the bearings and they would not seat any more. Cleaned up the ridges that was at the seat where the bearing stops , .030"high and .015" thick. The bearings seated finaly but just wondering was this just my bike or have others had this same problem getting the head steady bearing to seat and why such a tight of a fit?

Just asking.

Chuck W

Click to expand...

I think you mean the steering head bearings. The head steady typically refers to the connection between the cylinder head and the frame.

And you want a snug fit for the steering head bearings.

"Headstock" is also a reference to the steering neck.

ChuckW said:

Just asking.

Does anyone else have problems seating the bearings in the headsteady or is it just me. To get the old ones out I had to use a 16 lbs hammer. When I put the new ones in I had a .120 " gap between the spacer tube and the bearings and they would not seat any more. Cleaned up the ridges that was at the seat where the bearing stops , .030"high and .015" thick. The bearings seated finaly but just wondering was this just my bike or have others had this same problem getting the head steady bearing to seat and why such a tight of a fit?

Just asking.

Chuck W

Click to expand...

Chuck,

You always want to seat the bottom bearing first. It carries all the weight of the bike and the upper bearing is designed to adjust its position to it, by way of the spacer. There is a special tool for installing them but you can make your own, even out of wood. So long as you use a long bolt or threaded rod to install the bearings, no hitting.

Didn't have that much problem with mine. You're bad as shit if you can hold a punch with one hand and pound on it with a 16# sledge with the other.

Danger Will Robinson!!!

Be extreamly careful when seating steering head bearings! If you don't get them perfect your motorcycle will and when that happens you will experience what is termed a "tank slapper", and if that doesn't kill you it will most likely convince you to take up another avocation.

Knock out the old bearings, you've done this. Clean and de-burr the steering head bearing locations, lightly lub the steering head bores; start the new bearings. Use a threaded rod and the old bearings to properly seat the new bearings; you need some serious torque. Please don't beat new bearing as you will brinnel then (injure the races and create knotches).

Once you have been on the road for 10-15 miles, go slow over some rough roads, recheck your yokes for vertical play, do this again at 100 miles or again and again until the yokes stop showing play.

I had a tank slapper back in 1973 that I will never forget; on a large numbered state road my steering head bearing finally seated at 95 mph. The Triumph Trident I was on went from one break down lane to the other, thank God there was no traffic. About the time I got the balls to put the bike down it corrected; I limped home and changed my underware; two weeks later I discovered the loose front end...

Please be safe.

Re: Danger Will Robinson!!!

RoadScholar said:

Use a threaded rod and the old bearings to properly seat the new bearings; you need some serious torque.

Click to expand...

I was looking at that tool and trying to figure out how to make something like that. And then you say just to use the old bearings. So simple.

RoadScholar: My only SERIOUS tank slapper also came on a Trident (T160), at about 90+.

Like you, I was at the point of seriously considering "offing" it in the grass which looked much more inviting than the pavement & oncoming traffic.

Loose spokes on rear wheel (it was the maiden voyage on the bike when I first bought it, and I didn't do a pre-ride once-over)

If you don't have the tool or don't want to make one, a quick trip to a bicycle shop with your frame and bearings will get them in. Bicycle shops usually have heavy duty head set presses and those bearings will be in your frame in under 2 minutes and probably only cost you a latte for the mechanic or $10.

I did use a 5/8" by 1 foot threaded rod and also used the the old bearings to properly seat the new bearings as RoadScholar suggested. And I did need some VERY serious torque the last .10 of an inch to get them to seat. The spacer tube is now nice and snug and the bottom bearing is fully seated.

And just for the record when removing the old bearings I did not hold the punch in one hand and pound on it with a 16# sledge (I wish I could) I was a two man job. I held the punch and my friend hit it with the sledge.

Chuck

Luckly, you don't have to worry about the "tankslapper" in the case of a Commando. The Triumph used a cone or tapered roller bearing which are very sensitive to pre-set and seated races. The ball bearing setup in the Commando is not, in that regard. But it does help to get the bottom race seated where it belongs first and then let the spacer do its job. Torque it to your heart's content. The upper bearing floats to the spacer.

The point is that the bottom bearing has to be seated first by drawing it up to its seat with the threaded rod bearing down on the headstock by way of a cap or plate. Then install the spacer and top bearing using the threaded rod again to press the upper bearing-spacer-bearing togther.

my original sealed bearings were pretty tight in there. I had to use a mini sledge to get them out also... I replaced with tapered bearings, and just used a socket on the outer race cage to seat them. The new ones went in a lot easier than the old ones came out that's for sure