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GPz 750 Aircooled (85)- Starting Issues

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Fluffy Bunny Feet, Sep 12, 2006.

  1. Wondering if anyone on this forum ownes/owned a GPz 750 aircooled (ZX750/KZ750) which had starting issues, namely it sounds like the starter clutch isnt throwing in properly, it grabs for half a second and then makes that horrible scraping scratching sound a starter makes when it doesnt want to throw in...

    We pulled the motor apart after it started happening and noticed the cam chain spring was damaged (squished) to a certain extent, does incorrect tension stop this starter/clutch from throwing in properly? Unfortunately I have to wait 4 weeks for the genuine Kawasaki one to get here from Japan (they cant post a $3 spring in airmail even if I pay the bastards!)...

    I put a spring in there which sort of matches but still no avail, and we also pulled out the starter clutch, it spins freely on the secondary shaft one way and locks in and grabs the other, this is by hand pressure tho, is there a proper way of testing it with force?

    I'm pretty sure the starter is ok, we've pulled that out and tested it on a the bench and it happily ground up a plank of wood under power...

    any ideas? cheers!
  2. for these starter mechs its the dia that is gripped its critical that it is not marked (flats scores etc) it must look like the outside of a bearing race

    The next thing to check is the ramps where the rollers slide in again they must be flat and no grooves marks etc if minor scoring is present it may be stoned out with a round arkansaw stone (toolmakers supplier)

    Its then new springs from mr kwaka (do not use she will be close enough mate the damage will be amazing to see trust me do not do it) and some new rollers at the same time. The rollers will have minor flats etc all around them thats what causing the skidding grinding munching noise as they skid all over that dia thats supposed to be nice and round with no marks etc

    Keep in touch and good luck laverda 120 degree cranks would eat starter clutches on a weekly basis given the chance
  3. There is known fault with the GPz750 when the wiring gets old.

    Im gonna be a bit rough on this, but bare with me.

    Normally the ignition goes thru then main relay and then to the starter.
    Mine has been rewired with a second relay, to bypass the draw of the main relay. So essentially the juice gets a direct dump to the starter.

    Its something like that.
    It was a while ago that mine was done.
    Ill take some pics tonight to illustrate better.


    *i reserve the right to be totally off the ball with this comment :p
  4. The advice above is good. But, I'd rebuild the starter clutch if you have access to it now. Just do it, even if it apears good. They are a bugger to get to, and DO eventually wear out.
    My Z 650 (basically the same as your GPZ)had two defective springs in the starter clutch when I got it, it would barely turn the engine, and then only a half turn at a go, then throw out and make the sound I think you describe.
    And Kawasaki wiring can get flaky when old too, the relay trick sounds great.

    Regards, Andrew.
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  6. I forgot to mention, when you reassemble the starter clutch, thoroughly degrease the threads for the bolts that join it all together and make sure you use Loctite.

    Regards, Andrew.
  7. Yep starter clutch FUBAR!

    couldn't see it when we pulled it off the secondary shaft but when the one way gear itself is unbolted from the unit i could see it cracked right through the steel, that little metal plate holding the bearings in covered the crack so it couldnt be seen from the front of the unit...

    All fixed, now i just need to find someone to tune these quad carbs ughhhh....