How much play should there be?
When I turn the secondary back and forth without turning the jackshaft I noticed alot of play.
I rigged up a stationary pointer from a coat hanger and positioned it so it was pointing on the outer edge of the sheave. I turned it clockwise untill it stopped and marked the sheave at the pointer. Then I turned it counterclockwise untill it stopped, (NOT turning the jackshaft!), and put another mark on the sheave.
Measuring between the marks I'm getting 5/16" !

I noticed the play last year, and when I had the secondary off a couple months ago for cleaning I checked the following:
1. Jackshaft keyway groove
2. The key itself
3. The keyway groove in the secondary
It didn't seem like anything was excessively worn, but there was a little play when I placed the key in the jackshaft groove, and also a little play when I placed the key in the secondary groove. The key really does not look like it is worn.
I'm thinking it's a combination of a little wear on all of the parts, and when assembled the problem is compounded.
I'm going to replace the key with a new one and see if it helps, but I don't think it will.
I'm trying to avoid hammering the fun lever out of the hole but with the black magic clutch set-up that is on it,(I bought it this way :( ), it's hard to do because it's engaging at 5,000RPM.
What do you guys recommend? Is this too much play? Could I possibly break something if I really gun it out of the hole?
Thanks for any advice!

I noticed the same thing on my ZR580 EFI when I had everything apart a couple months back to replace the jackshaft and trackshaft bearings. I spent the 2 bucks on a new key, and it tightened it up a bit, but there's still some slop (maybe about a 1/4" measured at the circumference of the secondary clutch).

I think your right, it's probably cumulative wear on all the parts since nothing in itself looked excessively worn...

A couple of my buddies own ZR's. Next time I see them (hopefully Monday if it snows!) I'll try to remember to check how much play they have on thier sleds secondaries and let you know.

Hope this helps!

I was looking at mine last week and it has about as much slop that you metion.
my sled also has a bm cluch kit that engages at 5000 rpm.
The stock engagement on my 99 zr 600 is 4800. I did not pay to much attention to
were it was on the tach when it was stock but I never had the tack calebrated
so it could be off by a bit. I dont have the aswer to your question but I would like
to know if replacing the key takes up some slop.

If it's wearing out then just run it it the key is still driving the shaft. I believe there is still life in it eventually the parts will need replacement and worse case it will roll the key. I wouldn't mind it a bit. When it rolls the key you can deal wit it then.

I just remembered I found a badly worn secondary keyway groove on my '80 Scorpion Sting 440 a couple of years ago.
I called Ernie at Winter Haven to buy a new one. He had new ones or used ones that he had machined with two extra grooves, so when one groove got worn you could just use another groove. I think this was a normal problem on the old scorpions.
So I just had a buddy that worked at a machine shop put two more grooves (I think the correct term is BROACH?) in it.
It worked fine, and I still have an extra groove to use.

Could this be done to my Tcat secondary?

Could I also do this to my jackshaft?
And then with a new key it should be like new. And it would cost me alot less.

What do ya think?

Absolutely!!!

Thanks spaceman!
The snow we got over the weekend melted today :( so I'm going to look into doing it.
I just had my jackshaft out and replaced the bearings. I wished I had thought of it then.

I really want to be able to hammer it out of the hole and not worry about rolling the key.

Just remember that secondary needs to move feely along that key way.

Both of my sleds are doing the same thing. So now I am in the process of determining the correct height of the key to be so it can't rock the slot if it is held snugly on all four sides. :D

Keep in mind that the farther you measure away from the jackshaft on your
clutch sheave the more exaggerated the clearance will be. It could have
.020 clearance in the key way, but the large dia. of the clutch sheave will
move 10x as far. The best way to check is with feeler gages or shim stock
between the key and the keyway. I don't know what the clearance needs to be for your clutch but a good service manual may list it. :D

The secodary key slot is a clearance fit. Most likely the shaft & clutch hub are hardend. The key stock is rectangular [flat]. Without a set screw the parts will move.
If there is no visible denting of the slots and no shearing along the length of the key then your fine. The key should NOT be stationary it should slide along the jack shaft.
Replace the key with an OEM from the dealer. While you're there grab a clutch and see if it moves.
I'm gona check my service mnl. to see if it even addresses it.