SF2 Swingarm - Frame Gap

[ksoholm]

Lads,

I tried this Q on FB, but there's a spectrum of answers. During the test fitting of the swingarm without tightening the nuts and without the engine installed, I found 1-1.5mm end play between the swingarm bush and the frame flat.

There were no shims to take up the gap, the parts manual don't show any, nor does the Green Book reference them; it states that tightening the nuts takes up the endfloat.

Once the pivot pin nuts are tightened, is this end gap reduced? Will the ends just be rubbing away at each other brass-on-steel with a little bit of clearance keeping them from binding? How much clearance should there be once the nuts are tightened? Are we just relying on a bit of grease between the bush surfaces?

Thanks all -

 

[Paul Marx]

I have nylon spacers on mine.
You'll crack the frame if you tighten it like that.

Paul

 

[ksoholm]

Green Book: "Once the pin is out, the frame should have sprung apart enough to allow the easy removal of the swingarm complete."

Apparently only roller bearing models have nylon seals/washers.

 

[Paul Marx]

Green Book: "Once the pin is out, the frame should have sprung apart enough to allow the easy removal of the swingarm complete."

Apparently only roller bearing models have nylon seals/washers.

There is a thick washer on the parts list. The frame cracks around the lower engine mounts as it is, why stress is even more? Just look at the gap.
I put nylon spacers on my SF2 on which I put needle rollers.

Paul

 

[helicopterjim]

First question is how well does the frame fit the motor? Is the spacing of the engine mounts similar to what you have for the swingarm? If the motor mounts are spaced properly then definitely I would consider making spacers for the swingarm. If the motor mounts are spread wide as well then I would investigate to see if you have any problems with or damage to the frame.

I am guessing that the swingarm has the bronze bushings but I can't be sure.
Just for reference ..... looking at the Paradies site there are two spacers included in the kit to convert to needle bearings. I am presuming this is because the bronze bush incorporates the spacer in the lip of the bushing.

Jim

 

[ksoholm]

Paul, the factory SF2 parts manual does not show spacers between swingarm bush and frame flat (see attached page from a factory SF2 parts manual), nor does any shop manual or the Green Book reference them. The spacer you reference is the washer for the axle pin and nut.

That is not to say that it wouldn't be a good idea to use brass, aluminum, or copper, shims on ea. side as sacrificial metal and for smoother contact.

 

[Paul Marx]

Paul, the factory SF2 parts manual does not show spacers between swingarm bush and frame flat (see attached page from a factory SF2 parts manual), nor does any shop manual or the Green Book reference them. The spacer you reference is the washer for the axle pin and nut.

That is not to say that it wouldn't be a good idea to use brass, aluminum, or copper, shims on ea. side as sacrificial metal and for smoother contact.

You're right for the axle nut washer, but put a spacer in there anyway.
My 3C needed a spacer made up when I put the engine in. 2mm from memory, upper rear engine mount.
These contraptions are hand made.

Paul

 

[ksoholm]

You're right for the axle nut washer, but put a spacer in there anyway.
My 3C needed a spacer made up when I put the engine in. 2mm from memory, upper rear engine mount.
These contraptions are hand made.

Paul

I've been searching high and low for a good brass, copper, or aluminum spacer, in the right size; might even do steel.

 

[piranha-bro2]

You have the original bronze bush. The pivot spindle pulls up tight against the inside frame journals when you tighten the swingarm axle. It's not at all unusual to have a gap there with spindle out. It doesn't take a huge amount of pressure to bring the faces in. What is absolutely imperative is that once tightened, the swingarm rotates freely.

Definitely no plastic spacers with bronze bushes - plastic washers are thrust washers on the later SF3 needle roller setup, which many owners upgrade to once the bronze bushes/spindle are worn out.

I reckon following Jim's idea of checking engine mount spacing when pulled in is the best route to take. I'm guessing the engine came out easily with the swingarm in place so adding spacers is only going to reduce that engine mounting space and will potentially make fitting the motor very difficult.

If you do want to space it I would only use steel, as the outer lip of the bronze bush bears directly onto it; you are basically just reproducing the frame journal (the large round washer welded to the inside frame).

AFAIAC if it came from the factory without spacers, that's how it should be - engine mounts break for many reasons, I doubt this is one of them.

 

[ksoholm]

Good advice. I just bought 316 stainless shims from McMaster-Carr. I saw your comment from an earlier thread that when pulled tight, the pivot spindle will butt against the frame journal to allow free swingarm movement, but the spindle feels near as dammit exactly as wide as swingarm bushing-to-bushing. I'll see to it that it isn't overtightened and moves freely.

 

[piranha-bro2]

You should be able to tighten it very securely without binding the swingarm - definitely don't wimp on it! I found on my SF1 that the spindle had virtually seized (young, ignoramus re maintenance, grease dried up, rust and corrosion got in!) and the spindle began to rotate and wore itself into the frame journals - not an uncommon sight for regular repairers such as Piet.
You can test it off the bike by bolting up against a steel plate on each side of the swingarm pivot - drill a hole for the axle in the steel for each side. Bolted up very tight it will tell you if you have sufficient clearance. Also important that the journals on the frame aren't damaged as mine were.
You don't want any more than a poofteenth side play once tightened (for obvious reasons).

 

[Vince]

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