Rear axle play under heavy braking

Just put a new chain and sprocket on this week and thought everything was good until I had to really get on the brakes today. After that the rear end was super slippery, and as it turns out the axle moved. I found a 1/4 inch gap in front of my right hand rear wheel adjustment screw. I'm thinking one of my spacers was in the wrong spot. Everything matches the diagrams I've found, but I'm not sure about the thin, washer like spacer. It was on the outermost side of the adjuster, behind the head of the axle. I'm at a loss as this shouldn't be physically possible. I'm in desperate need of some KZR wisdom. Bike is a 79 1000 c2. Sorry, had to link to my pic because I'm on mobile and can't take a pic within the forums size limits
i.imgur.com/vLwrHWQh.jpg

Perhaps the adjuster screw's lock-nut wasn't sufficiently tightened, and allowed the screw to vibrate out of position.

Good Fortune!

I'll definitely double check my lock nuts this time. I found this diagram, and according to it the thin spacer goes beneath the castle nut. I didn't have mine there, but on the opposite side. Could that have been part of the problem as well?

Yes it goes under the castle nut. The nut has to be torqued down to at least 50 lbs. Also you need a cotter pin or quick release pin.
Steve

Hitch pin clip is less likely to draw blood when not-so-carefully wiping down the bike.

Cotter pin -- OUCH! -- Where are the band-aids? :pinch:

The clip is far easier to remove and replace -- over and over and over.

And besides, the clip looks a whole lot classier. :woohoo:

Good Fortune!

Yeah, I have them on my bike. You can get them at any hardware store. I had cotter pins. PITA :lol:
Steve

So I reassembled everything, put the spacer where it belongs, tightened the absolute shit out of the axle, put a new pin in, and it still does it. Locked the brakes up in the drive way and the axle moved again. Same side, same distance. The screw definitely didn't come loose .

Seems I wasn't torquing it enough. She's looking solid now. I also snagged a hitch pin and will never bother with cotter pins again.

Of course after torquing, the use of a pin or clip is for back up safety measures. If torqued down, that nut will never come loose. I never put cotter pins or clips in, just tighten the nut. Not that I recommend it, but just for info that the nut isn't going to come loose ever should you desire to not fool with the clips or pins ect.

Will it move now? The clip is there for a reason. I suggest using one.
Steve

I never understood the need of the clip really. If you look at newer motorcycles, not one uses a clip. Simply tighten the axle to spec, and done. All my newer motorcycles are this way. How many bolts/nuts tightened to 80ft/lb come loose? Not one in the last 200yrs, but if the clip makes you more secure, it doesn't hurt I will say. Bottom line is not needed, but doesn't hurt.

RonKZ650,
What year is your KZ650? My first KZ was a 1977 KZ650. I had a blast with that bike. Bike was candy apple metallic green. I did a ton of mods to it and then sold it so I could buy a 1980 LTD 1000.

Some of the mods to my KZ650 were, changing out spoke wheels for after market Lester wheels. I then ended up trading my Lester Wheels with a buddy of mine that owned a SR650. He loved my Lester wheels and had to have them, so he offered me an even trade on SR650 swingarm, and 16 inch rear wheel/tire combo, plus disc brake setup for the rear. PLUS the front wheel from SR650, with dual disc front brakes. I removed stock "duck-bill" tail and replaced with a Z1 tail, painted to match original KZ650 green. Miss that bike. Enjoy yours.