Swingarm Pivot bolt torque?

[BrianG]

Having just completed the remounting of the swingarm, investigation reveals that the swingarm simply pivots on the bearings which are located by the fine-threaded stub shafts in the pork chops. The lateral location of the swingarm is defined by the penetration of those stub shafts.

 

So far so good.........

 

Now that I have located the swingarm in the appropriate place, laterally, how does one finalize the postion of the stubshafts related to their contact with the swing arm?

 

That is.....

Is there some load to be left on the swingarm by the shafts, by some torque load? This seems unlikely...

 

Is there a certain amount of "back-off" from firm contact against the swingarm? This seems reasonable, and feels like zero lash at about -1/2 turn of one stub shaft.

 

I can find no reference to this issue here, nor on GuzziTech.

[Greg Field]

Brian:

 

You do not want to preload the bearings. Just take up the slack. With wheel off and sock rear bolt undone, wiggle the swingarm up and down and side to side. Adjust out any slop you can feel. Then, do the same while watching at the pivots for any slop left. You can see slop that you cannot feel.

[dlaing]

Hi Greg or whomever knows,

What about torquing the steering head bearings?

Same strategy, or can they handle more torque?

There was a fairly recent discussion on this, but without a definative answer.

[Greg Field]

I have yet to see a device to accurately measure the torque on steering-bearing adjusters. The theory is to take up all the play and hold them at whatever torque that is. Again, you can see freeplay that you cannot feel. Look at the line formed by the top or bottom of the bearing tunnel. As you try to wiggle the forks you will see any relative movement between that line on the frame and the triple clamps. Adjust until you see no relative movement and lock the locknut.

[BrianG]

Hi Greg or whomever knows,

What about torquing the steering head bearings?

Same strategy, or can they handle more torque?

There was a fairly recent discussion on this, but without a definative answer.

 

There seems to be a vast difference in bearing "pre-load" depending upon which type bearing is in use. It appears to be related to the size of the "contact patch" of the elements. Rollers having larger contact patches than balls.

 

That said, in the environment of the steering head, there is not much radial load, but mostly axial load. In this circumstance, one would suppose that zero-lash would be the goal, as opposed to significant pre-load.

 

I have liked the practical results provided by an old Honda specification. The old VFR specified 4 lb. ft. resistance to steering head motion. That's a whole lot less than 20 lb.ft. torque on the stem bolt! I use 20 lb.ft as the initial set torque to satisfy bearing race seating. I then back off to zero-lash (by feel) and just add very small amounts of turn to the headbolt nut until I get the 4 lb.ft. turning resistance.

 

You don't want to see my system of stick-strapped-across-the-forks / string / pulley / coke-bottle-filled-with-4 lb of water.......

[Guest ratchethack]

Hi Greg or whomever knows,

What about torquing the steering head bearings?

. . .

Dave, there seems to be surprisingly little decent info on this on the Web, but I was curious wot would be out there, and found the following (see link below).

 

Tapered rollers have been industry standard in steering heads for about 30 years now and they're pretty much all the same WRT maintenance and adjustment. The following is a generic write-up for Harley cruisers, though it's hard to conceive how it wouldn't apply to V11's.

 

It's a pretty good write-up and it's lengthy (see link below), but the gist of it is this:

The bearings must be preloaded to the manufacturer's specifications. In some cases that means tightening the nut to some initial torque, backing it off and then resetting it to the suggested preload. If no specs are provided or they seem vague, you'll need to use a little Kentucky Windage. Using moderate pressure, bottom the adjusting nut until the stem starts to bind. Rotate the steering stem back and forth a few times, then back the nut off half a turn. Repeat the tighten, turn, loosen cycle several times, always turning the steering stem from side to side. For the final adjustment, draw the nut up snugly and then back it off a turn. Don't be too concerned if the stem feels a little tight at this point—it'll free up as you install the rest of the front-end parts.

Full article here: http://www.motorcyclecruiser.com/tech/serv..._head_bearings/

 

This all seems to make pretty good sense except for this sentence - "For the final adjustment, draw the nut up snugly and then back it off a turn." Now backing it off a FULL TURN afterward is beyond me, and I seek further guidance from higher expertise for an explanation?! If I did this, it would NOT feel at all "tight", it'd be er, loose as a goose (so to speak), and have an audible clunkiness and easily felt play that I wouldn't want any part of!!!!

 

Again, I've always used ~20 lbs-ft, torque and left it there. This is wot's spec'd for my XT600.

[Guest ratchethack]

I have liked the practical results provided by an old Honda specification. The old VFR specified 4 lb. ft. resistance to steering head motion. That's a whole lot less than 20 lb.ft. torque on the stem bolt! I use 20 lb.ft as the initial set torque to satisfy bearing race seating. I then back off to zero-lash (by feel) and just add very small amounts of turn to the headbolt nut until I get the 4 lb.ft. turning resistance.

 

You don't want to see my system of stick-strapped-across-the-forks / string / pulley / coke-bottle-filled-with-4 lb of water.......

Brian, I always appreciate a creative Rube Goldberg setup , having put together some impressive amalgamations of my own, if I do say so meself....

 

Now you've got me goin' on this....

 

With the front wheel off the floor and ~20 lbs-ft. torque on the adjuster nut, I have FAR LESS than 4 lbs-ft. turning resistance at the bars -- with both of my bikes!

 

Here's a "precision" measurement. With the Guzzi front wheel off the floor and steering damper halfway to "at speed" setting, I can turn the bars at will lock to lock in either direction, pushing with the "retractor button" on a ball-point pen at the end of the bar-end weights -- WITHOUT clicking the pen!!! Now THAT would seem to be far less torque than 4 lbs-ft., n'est-ce pas?

[rossoandy]

Brian, I always appreciate a creative Rube Goldberg setup , having put together some impressive amalgamations of my own, if I do say so meself....

 

Now you've got me goin' on this....

 

With the front wheel off the floor and ~20 lbs-ft. torque on the adjuster nut, I have FAR LESS than 4 lbs-ft. turning resistance at the bars -- with both of my bikes! Here's a "precision" measurement. With the Guzzi front wheel off the floor and steering damper halfway to "at speed" setting, I can turn the bars at will lock to lock in either direction, pushing with the "retractor button" on a ball-point pen at the end of the bar-end weights -- WITHOUT clicking the pen!!! Now THAT would seem to be far less torque than 4 lbs-ft., n'est-ce pas?

aaaah ratchet does that allow for the differnt spring rates used by the likes of Parker v Biro in their pens!! and what about adjustable pre load pens? he he

[BrianG]

With the Guzzi front wheel off the floor and steering damper halfway to "at speed" setting, I can turn the bars at will lock to lock in either direction, pushing with the "retractor button" on a ball-point pen at the end of the bar-end weights -- WITHOUT clicking the pen!!! Now THAT would seem to be far less torque than 4 lbs-ft., n'est-ce pas?

 

I would certainly seem less than 4 lb force but my bar end weight tips are at almost 16" from the steering stem center so you are cheating with a bit of extra leverage. Not much perhaps but some.

 

I have not gotten around to this part of the winter rejuvination project just yet but it's coming, so I haven't anything to add to the Guzzi-specific situation yet.

 

I might add that the VFR steering head did have cage-captured ball bearings, however.

[Guest ratchethack]

Now that we've fully hijacked your thread, why not just continue?

I would certainly seem less than 4 lb force but my bar end weight tips are at almost 16" from the steering stem center so you are cheating with a bit of extra leverage. Not much perhaps but some.

I just took a measurement. My pen-click torque point is 14 3/4" from steering-head center point. But yes, I was trying not to get it to click, since it was "on the verge". But if I'd backed out the steering damper, it would've been a bit easier yet.

 

The ball-bearing headset in your VFR is far more the exception than the rule in recent years. It does remind me of the '60's bikes I've owned in that regard, where more than one time the non-caged bearings would make for great fun finding the last one or 2 after they all came out and ran f'er the deepest darkest corners of the garage in nice even angle increments across all 360 degrees of the compass...

 

I reckon all torque spec's would be in an entirely different class with ball bearings, just as you pointed out earlier. 'Nother words, the setup spec's for tapered roller headsets don't apply, and vice versa .

 

EDIT: The Guzzi was already on the stand, so I gave the bearings a check, since it's been awhile. With steering damper backed off, the bars flopped against the stops anywere past halfway there. I put more torque on the adjuster nut -- I'm figuring around 25 lbs-ft. -- cycled it a few times, loosening and tightening between cycles. I left it at about 25 lbs-ft. Now it shows a tad more resistance to turning, but will still flop against the stops on its own within 10 or so degrees of the stops, either side.

 

It's got consistent "pen click" torque on it now in both directions from center position -- but just barely.

 

I reckon this is about right, but I'm going mostly on memory from many previous bikes with similar tapered roller headsets. Somebody please tell me where I've gone wrong if you know better??

[Guest ratchethack]

aaaah ratchet does that allow for the differnt spring rates used by the likes of Parker v Biro in their pens!! and what about adjustable pre load pens? he he

Good one, Andy -- Different rate springs f'er different pens. Yes, indeed. But as you know, preload doesn't have any effect on spring rate, so preloaded in "ball-point out" position and "ball-point in" preload positions both allow the same torque at the bar-ends! !

 

How else to measure such low steering resistance torque? I dunno without invoking the spirit of Rube Goldberg.

__________

 

Rube Goldberg gets his think-tank working and evolves the simplified pencil-sharpener (see below).

 

Open window (A) and fly kite (B ). String © lifts small door (D) allowing moths (E) to escape and eat red flannel shirt (F). As weight of shirt becomes less, shoe (G) steps on switch (H) which heats electric iron (I) and burns hole in pants (J). Smoke (K) enters hole in tree (L), smoking out opossum (M) which jumps into basket (N), pulling rope (O) and lifting cage (P), allowing woodpecker (Q) to chew wood from pencil ®, exposing lead. Emergency knife (S) is always handy in case opossum or the woodpecker gets sick and can't work.

[BrianG]

Alrighty then...........

When I get to the front end, I'll whip out the trusty torque wrench and get a number on what it takes to resist 2 liters of water pulling on a 1' stick.............

 

Should be interesting.........

 

I haven't looked yet, but does MG specify a steering stem nut torque setting for the V-11's?

[Guest ratchethack]

I haven't looked yet, but does MG specify a steering stem nut torque setting for the V-11's?

Nyet. And there, my friend, lies the rub!

 

On p. C 15 of my Guzzi Service manual, it has STEERING ADJUSTMENT instructions, with a nice photo and letters for parts in sequence of a procedure.

 

The "critical part" of the 4-bullet procedure is:

 

"Tighten or unscrew the adjustment nut "C" until the backlash is correct."

 

Any guesses how many possible interpretations of "backlash" can be imagined here by backwards translation into Italian?

 

One might assume that since there's no torque spec'd., that zero torque is called for. I ain't prepared to make that assumption -- but that's just me.

[BrianG]

One might assume that since there's no torque spec'd., that zero torque is called for. I ain't prepared to make that assumption -- but that's just me.

 

I figure zero backlash is the critical issue. Bearing preload here isn't going to be a major concern if there is free movement of the forks.

 

My take would be that preload torque on the steering head nut must be >0, but

 

By the way..... the 4 lb resistance also contemplated newly grease-packed bearings. Are yours recently packed?

[Guest ratchethack]

My take would be that preload torque on the steering head nut must be >0, but <impediment to motion. If 20 lb.ft. torque provides little to no resistance to motion I'm good with the fact that there can also be no lacklash, either.

 

By the way..... the 4 lb resistance also contemplated newly grease-packed bearings. Are yours recently packed?

This would seem to be a reasonable take, Brian.

 

The Service manual calls for adjustment at 12K and 24K miles, with no listing at all for lubing the headset up to 30K, and that's as far as the chart goes, the assumption being that the intervals established to that point continue as before beyond 30K, many important omissions within and beyond that notwithstanding.

 

I've faithfully followed the schedule (and then some), and the headset has been silky smooth with no indications of running out o' lube, so I ain't been too concerned about it yet at 31K. It'll get a full cleaning, inspection & lube at next fork oil change at 36K.

 

BAA, TJM, & YMMV