Tonti swingarm installation

[brider]

I'm having a bee-otch of a time installing my freshly-painted swingarm with new bearings on my Cal 2 Auto. Seems very much like the bearing spacers are a HAIR too wide for the spacing in the frame, I just can't get it to slide into the "flats", even though I think the u-joint yoke is aligning on the tranny output.

On the bench, the swingarm bearing spacers that the bolts slide into appear perfectly flush with the swingarm housing, so it's hard for me to believe the new bearings are at the high-side of their tolerance and pushed the overall side-to-side width of the spacers too far out.

I know the concept is simple; am I missing anything in the sequencing?

[Perazzimx14]

When I did the swinger on my T3 had the same problem. But as Chief Dan George says endeavor to persevere. It'll go but its a tight squeeze. Also doesn't hurt to tape off stff you don't want scratched.

[acogoff]

    You may find this old thread useful.

    https://wildguzzi.com/forum/index.php?topic=74888.0

[Thirtyaughtsix]

On my particular T it was a complete nightmare, I've had mine on and off so many times now dealing with throwout issues that there's no paint remaining on neither the swingarm or frame right there. Granted every time I was working from the ground with the bike on its center stand, I'd like to think I would have had a better time had it been on a proper bench so hopefully you have at least that.

For me it helped having the swingarm void of the u-joint and shaft making it as light as possible, I myself had to work it in one side at a time, left and then right, and I did so with the swingarm at about a 30 degree angle or so, like you're lifting the arm up into the frame almost. Definitely shlack up those spacers with grease so they stay in place for you, I had to anyway. Hope that helps, good luck

[twhitaker]

swingarm void of the u-joint and shaft

I think you meant final drive instead of u-joint.

[fotoguzzi]

The rear of swing arm must be angled down, like to the floor.

[Chuck in Indiana]

From the above quoted thread.. the answer by Mike Tiberio, I think this is key..

Of the 4 big frame bolts (2 per side to attach lower frame rail), 1 only one per side (the rearmost), and I do not insert them beyond flush on the inside

Tighten them back up after the swing arm is loosely installed.

[brider]

Thanks, all, I will take everything suggested into action and report back.

This is being accomplished on the cold garage floor with the bike on it's centerstand. Bunch of big scratches now in my new swingarm paint   

[John A]

When those bolts are out the upper frame and lower frame can easily come out of position in relation to each other and block the installation of the swingarm. It's what bites me in the ass until I see it...

[brider]

Well, La-dee-frickin'-da, I removed the (2) remaining frame bolts that were gouging the @%$#&*! out of my new paint, lowered the swingarm down as low as it could go, and Bob's yer uncle, it slipped right in.

I was almost ready to call BS on Rodekyll's claim of 45 sec, but I'll bet I matched that, easy.

Thanks, all!

[Chuck in Indiana]

Well, La-dee-frickin'-da, I removed the (2) remaining frame bolts that were gouging the @%$#&*! out of my new paint, lowered the swingarm down as low as it could go, and Bob's yer uncle, it slipped right in.

I was almost ready to call BS on Rodekyll's claim of 45 sec, but I'll bet I matched that, easy.

Thanks, all!

Well, there ya go.. gotta love WG..

[Antietam Classic Cycle]

So much easier on a Loopframe...

[Perazzimx14]

Took the swingarm off the SP today. Cleaned, pivot pins, races and bearings then repacked the pivot bearings also checked the U-joint and drive shaft (both which looked like new). Cleaned off any old rust, crust, grease or moly and reassembled. Reapplied new coat of moly paste 60 and went back together a treat with no drama.

I was sort of dreading the job of checking the rear (because of the potential of more money being needed) but after my fork episode it wasn't getting over looked and ended up being a nice little afternoon project.

[canuck750]

I have tried getting the swing arm into a Tonto frame without removing the frame lower bolts, not possible, took me couple rebuilds to learn that simple lesson

[Chuck in Indiana]

I have tried getting the swing arm into a Tonto frame without removing the frame lower bolts, not possible, took me couple rebuilds to learn that simple lesson

Yep. Bump to the top to maybe get someone's attention eventually.

[brider]

So much easier on a Loopframe...

Yeah, a Loop was the last time I did this, that's why I was baffled by my initial difficulty.

New question: Is the swingarm lateral alignment dictated by it's snug-to-net fit between the frame "flats", or should the pivot pin thread protrusion on each side be equalized? Seems to me that if the fit between the frame rails is very "snug", then tightening the pivot pins much beyond fully-seated (regardless of thread protrusion) will begin to preload the frame.

What is the preferred procedure here?

[Chuck in Indiana]

I run the screws in until they touch, measure each, then loosen the low one, and tighten the high one until they are the same. You can "feel" the fit by raising and lowering the swing arm to tell you just how tight the screws should be. Hold it there with your wrench, tighten the big jam nut, and you're done.

[mtiberio]

the double u-joint on a guzzi is tolerant of side to side mis-alignment. Heck, some of the last Tonti Californias had that looong u-joint that specifically was offset to fit larger tires. I wouldn't trust using a vernier to measure the amount sticking out as a way to insure the carrier bearing is centered over the output shaft. Too many variables, although it is a good first order solution. On many of my Guzzis, I shim the rear wheel to the left so the 120 tire (or 130 or 140 when I raced) clears the swingarm. In order to get the tire mostly back to the centerline of the bike, I then offset the entire swingarm to the right. YMMV. I know Charlie Cole on his racer used to offset his rear tire to the right of the centerline, why? It helps the bike corner into left hand corners and compensate for crankshaft inertia. After racing a Guzzi, you learn that Guzzis are harder to force over into lefts than rights. Charlies solution was brilliant, but it ultimately limited rear tire width.

[brider]

In order to get the tire mostly back to the centerline of the bike, I then offset the entire swingarm to the right.

Heeeere's where I get leery, even though I know I'll never apply enough preload to damage anything. My starting premise is that the swingarm bearing "collars" or spacers or whatever they are, are a NET fit into the frame where they mate with a machined (?) surface which the pivot pins protrude thru, into those 'collars".

I'll be sure to check again, but if there is as much as .030 clearance side-to-side between the swingarm collars and machined surface, I would be surprised, and my concerns will be cleared.

But if there is no clearance, or something like, say, .010 clearance, then really the frame geometry will dictate the lateral position of the swingarm, and when you lightly screw down the pivot pins until they bottom, then whatever thread protrusion there is, is what it is, and any attempt to equalize them MAY just draw the frame apart to INCREASE clearance on one side where before there was none.

Am I over-thinking this? Slow day at work.

[mtiberio]

Heeeere's where I get leery, even though I know I'll never apply enough preload to damage anything. My starting premise is that the swingarm bearing "collars" or spacers or whatever they are, are a NET fit into the frame where they mate with a machined (?) surface which the pivot pins protrude thru, into those 'collars".

I'll be sure to check again, but if there is as much as .030 clearance side-to-side between the swingarm collars and machined surface, I would be surprised, and my concerns will be cleared.

But if there is no clearance, or something like, say, .010 clearance, then really the frame geometry will dictate the lateral position of the swingarm, and when you lightly screw down the pivot pins until they bottom, then whatever thread protrusion there is, is what it is, and any attempt to equalize them MAY just draw the frame apart to INCREASE clearance on one side where before there was none.

Am I over-thinking this? Slow day at work.

If you recently had the swingarm painted or powder coated, it is possible that the outer races (the ones in the swingarm) were not fully seated. I have also heard of some tapered rollers which were slightly larger in the depth (axial) dimension. Once again if you used new bearings perhaps they are too wide. If preloading the frame bothers you that much, why not have a machinist skim the steel spacers?

[Tom H]

Per the book:
22.5 ADJUSTING THE SWING ARM PLAY (fig. 153) Ensure the swing fork oscillates freely without any play_ Be sure both spindles project by the same amount. This adjustment is best done using a screwdriver ŤAť and gauge .. e

This manual should be for your bike:
http://www.thisoldtractor.com/mg_manuals/workshop_manual_g5_sp.pdf

This should be a supplement:
http://www.thisoldtractor.com/mg_manuals/workshop_manual_california-ii_en.pdf

Hope this helps a bit,
Tom

[brider]

Thanks, Tom.

Rather than talk installation-theory, I'll just DO it when I get a chance between ice-storms.

[mtiberio]

I was told by Eric Phillipe (old part owner of the Lillington dealership that later became the national HQ of Guzzi), that the swing arm stubs only took about 1 foot pound. Clearly they do not take much.

[Chuck in Indiana]

I was told by Eric Phillipe (old part owner of the Lillington dealership that later became the national HQ of Guzzi), that the swing arm stubs only took about 1 foot pound. Clearly they do not take much.

Agreed. Too tight and the swing arm won't move freely. Just snug.

[jwinwi]

I run the screws in until they touch, measure each, then loosen the low one, and tighten the high one until they are the same. You can "feel" the fit by raising and lowering the swing arm to tell you just how tight the screws should be. Hold it there with your wrench, tighten the big jam nut, and you're done.

This is all ye need to know!