Rear Wheel Assembly

[egsols]

Just replaced tires on my 79SF. Noticed a slight gap between the torque plate and frame at the rear. I believe there should be a spacer on the right rear side but I don't recall one when I took it apart. When I look at the yamaha parts diagram I don't see one but the manuals speak of one.

The rear has the dust seal/collar, (looks like a hat) then the caliper then the torque plate and nothing else. I am about to check the rear on my spare and will post pics shortly.

My question is, should there not be a spacer between the rear wheel and the caliper? If so does anyone know the part number?

Lastly, the hole in the axle, to hold it from rotating when undoing the nut, seems to be slightil hidden by the frame. Should it not be 100% visible?

[blue giant]

Ernie,

I'm going to go out on a limb here and say you're missing a spacer. If I recall there should be one between the swing arm and caliper bracket. That would also explain why your axel bolt is inserted too far into the swing arm clamp. I just had the rear wheel off my XJ so I'm going by memory. I can double check tonite when i get home.

Cheers,

Paul

P.S. Did you find the covers for that fairing?

[newc4]

We just had this discussion under the thread "Rear axle, pinch bolts" thread.

In short, there is no spacer, the stepped axle does not require it.

Darrell

[egsols]

Okay, I checked my spare bike, also a 79sf, and it has a spacer between the hub and the caliper. When I got home I thought I'd take a picture of the rear and found the spacer. I had inadvertantly re-assembled the rear as it was before. I guess whoever had it off last time put the space on the wrong side. This explains why the hole in the axle is slightly into the frame.


Above shows the spacer being used as a washer.

And this is the gap left by not having the spacer.

As a lot of members have mentioned the same gap (between the torque plate and the frame), I wonder how many actually have the spacer behind the castle nut thinking its a washer?

[AlanB]

Hi egsols,

It IS a washer, and it DOES go behind the castle nut!

CLICK for DIAGRAM!

The space by the torque plate is needed to allow the right leg of the arm to "float" before it is clamped down by the pinch bolt. If the wheel assembly was meant to accurately fill the gap in the arm, the clamp and pinch bolt would be redundant; a conventional spindle with a hex head would be used.

The washer is to protect the alloy of the bevel from repeated tightening of the castle nut.

Hope this helps!

AlanB

[egsols]

Thanks Alan,

Douhhh!!! When I looked at my spare bike yesterday (in dim light) I thought I saw a spacer. I just had a look at it again and there is not a spacer, just dirt and grime.



The new is on the left with the spare on the right.

I guess that gap had me wondering especially since the manual states "be careful not to loose the spacer". I was also confused because when I measured the gap it was about 4.5 mm, the same as the thickness of the washer.

So I take it that the gap is normal and no cause for concern. I would assume that the caliper cannot slide due to the pads holding it in place on the rotor and as such would be considered self-aligning?

So what spacer is the manual talking about? The one for the torque plate labelled as 31?

[AlanB]

Hi egsols,

As you tighten up the castle nut, the shoulder on the spindle will clamp the torque plate and the caliper bracket to the spacer, which in turn gets clamped up to the centre spacers in the wheel bearings, and right through to the bevel box.... making one complete assembly. The pinch bolt the clamps the other side of the arm onto the spindle.

You should feel a certain amount of movement at the caliper bracket if the castle nut is loose, but you can only get sideways movement of the caliper bracket if the spindle is actually knocked back (to the right).

As the castle nut is tightened, the whole lot is pulled together, and the bracket is held tight. The caliper itself (not the bracket) must be able to move/slide or the brakes cannot work, so the caliper does not help to align any of the parts.

I would assume that the spacer they advise against dropping will be #23, since that is the only "loose" spacer.

Glad the diagram helped!

AlanB

[egsols]

Thanks again Alan,

I guess it wouldn't hurt top put a small amount of grease on the spindle (to keep the caliper from binding)

Probably #23, I remember dropping it a couple of times.

[John]

[QUOTE]Originally posted by egsols
[B]

So what spacer is the manual talking about? The one for the torque plate labelled as 31?



#31 is actually a rubber grommet to absorb the shock of the torque arm when the brake is applied.

[egsols]

#31 is actually a rubber grommet to absorb the shock of the torque arm when the brake is applied

I realize that its just that the picture in the manual throws me for a loop. The spacer I see looks like two larger washers sandwiching a smaller one?

At any rate I've got two bikes that look exactly the same so I'll put one together to match the other.