Z1OwnersClub GB

The rotor on the end of my Z1000A2 crankshaft keeps coming un done.
Done it since ive had the bike (7 years) this has happened every so often, always put bit of loctite on the bolt and done it up and would be all ok for a while.
Just recently its done it with in a few times of starting the engine.
So took the rotor off and had a look down the taper and it was badly scored.
Got a another rotor off Andy c on here and followed his advice on lapping it on to the crankshaft and all seemed well.
Done the bolt up to specified torque setting and the starter clutch locked up.
So jak came round to have a look only way we could get it to do up to specified torque without the starter clutch locking up was to remove the thrust washer and the rubber damper.
But after a few times of starting it rotor came undone again.
One thing to mention when you offer up either of the rotors they done grip onto the crankshaft and can pull them off fairly easily.
Any ideas guys?

i had same trouble some time ago,i got told that when you have torqued it up,hit it a few times with mallet,re tighten,then untighten,then torque it back up.if you understand that, ps,the normal torque for keyway ones is 18ft/lb,these need to be 100ft/lb torque.

hi mikey,
used the lapping method many times,usually does the trick.seems your crank prob has a lot of wear from previos slipping,which means now its lapped,the rotor has moved closer to crankcase,making the clearance smaller(hence locking clutch)
by removing the washer you got more clearance.so,maybe you need just a few thou more to allow the rotor to pull fully onto shaft.
also worth checking the bolt hasnt now bottomed out(try an extra washer on it & bolt it on without clutch to see if it will tighten)
im sure a few thou could be machined from something if need be.
hope you follow that & hope it helps!
skibs

Mikey your starter clutch boss could be worn. After a while it can get a bit lumpy - it doesn't take much but if you look closely you maybbe able to detect wear - so then the rollers spin out and jam and crack it off the taper no matter how well it's on. I had this issue with mine about ten years ago, new starter clutch fixed it and hasn't happened since though that's an A1. I think the old one's under the bench I'll take a photo or I may have a picture of it somewhere.

It's odd that you had to take out the damper you can get different sized ones from memory.

Thanks for the replies guys lots to look at
seems first off ive not been torquing it up tight enough as only torque setting i could find in any manuals i have was 18ftlbs but as hillbilly says should be 100ftlbs if not a key way crank
hey ho all the joys of keeping an old banger on the road.

That's really weird if the whole thing is locking up at only 18ft/lbs on the later crank.... From memory is the rubber damper not supposed to keep the whole thing out from the crankcase so if the damper is worn it could be compressing it up and locking it up, but with no damper it's not getting tight enough so won't lock up. Then it would be loose anyway and fall off.

ok tried hillbillys trick and it seems to be holding
kept starting it and switching off (counted 40 times) and its holding
usually by now its worked loose.
Undone the rotor bolt again and now the rotor is a firm tight fit on the crank and will need a puller to get it off.
But still not enough clearance for the thrust washer and the damper.
Will it do any damage to run it without these items.
So im lead to believe the damper and thrust washer are only there to stop in and out ward movement of the big starter gear?

Rotor bolts:
A2 is 18 ft lbs,
MkII ie A3, A4, is 94 ft ;bs

Not at all good to run it without the thrust washers.
You need to change the dished rubber damper.
There are three sizes denoted by one , two or three stars moulded on the inside of the dished part.
If you already have the thinnest then some light work on fine wet'n'dry (used wet) to remove material from the rubber edge that faces the crankcase is required to get the correct clearance so that the starter gear turns freely without binding.

Good point rob just had a check on my damper and it has 2 stars moulded in to it so im guessing i need the single star stamped one.

Rich,

not doubting your knowledge but when its torqued to 18ftlbs it just comes loose, and you can pull the rotor off but at the mo with it at the higher torque setting you need a puller to pull it off.

Just go by bolt size.
8mm bolt which is only used on 22mm keyway cranks is 18ft.
10mm bolt - all non keyway (still 22mm ) but pre mk2 are 95ft.
12mm bolt - mk2 and J/GPZ (25mm taper) around 95 to 105ft depending on which manual you consult.

Some more info here, this problem has been the bane of my life!!

http://www.z1ownersclub.co.uk/forum/vie ... highlight=

Rang Zpower today to order some bits and they say its perfectly
ok to run without thrust washer and rubber damper.

mikey wrote:Rang Zpower today to order some bits and they say its perfectly
ok to run without thrust washer and rubber damper.

WTF!
Perfectly ok if your intention is to f#ck up the starter gear and needle roller bearing.
You must have spoken to their cleaner

Thrust washers are there to prevent the hardened starter hub running against the crankshaft and rotor and the dampers role is to prevent starter gear wobble destroying the needle roller bearing.

Only saying what they told me.

Only other option is to take the whole starter assembly out and just kick start
it all the time cuz its seriously hacking me off.