Z100 motor locking up

[paul doran]

I have a Z1000 with a big bore kit I bought awhile back
I discovered that the previous owner had removed all the starter bits
starter clutch boss motor and gears
I replaced all these but after spinning the motor over a few times it locked
I took the cam cover off and I could see the motor was trying to turn once I pressed the starter button
I suspected it was in the alternator housing and once I removed the cover the motor spins freely
any ideas
I did replace the cover and the motor is still turning

[z1bman]

i thought the starter motor was supposed to turn when you pressed the starter buton???

[garyd]

Maybe it has the 'wrong' crank.

Can't remember which way round it is...but doesn't one of the later 1000s have a slightly longer crank on the generator side?

[KeithZ1R]

presumably youve checked the large starter gear spins freely dont they have to be shimmed up correctly ?

[zed1015]

Is this a big block engine ?
If the motor spins a few times then locks or slows down it's because it hasn't enough torque to crank the big block engine.
After a few spins the compression will build and overcome the starter motor.
You need to fit a later four brush GPZ starter or the even stronger CB900 starter and possibly a higher amp battery to cope (Motobatts are good for this)

I've recently done all the above to a 1395 big block Z ( had to use a 20 amp motobatt ) and it will still struggle if it doesn't start after the first few spins.

If it's just a 1075 big bore etc it sounds like something was wrong with the previous mechanics engine building competence and anything from the starter clutch to the valve timing could be the cause.

[paul doran]

i thought the starter motor was supposed to turn when you pressed the starter buton???

its not the starter motor that is the problem