After finally getting my '93 M900 back together the bloody thing won't start! It's turning over, just! At first I was thinking a bad battery, but three different batteries and a starter pack no differences! The starter solenoid is good. The only other thing I can think of is the starter motor.

Any other ideas, suggestions or comments?

bad earth?  crap leads?

Quote from: brad black on December 18, 2014, 02:32:31 AM
bad earth?  crap leads?

Leads are good, I was wondering about the earth as the frame has been freshly powder coated! Should I run a tap into the frame earthing point?

If I read you right, its bearly turning over with a good battery?? Didnt you change pistons and rings? Can it bee an tight fit sylinder/rings?

Quote from: Graymonster on December 18, 2014, 02:56:08 AM
If I read you right, its bearly turning over with a good battery?? Didnt you change pistons and rings? Can it bee an tight fit sylinder/rings?

Yes, I fitted JE Pistons and rings it turns by hand very easily please God don't be the Pistons 

Quote from: MonsterMadMarty on December 18, 2014, 03:03:49 AM
Yes, I fitted JE Pistons and rings it turns by hand very easily please God don't be the Pistons 

Crossing my fingers its a quick fix, running a tap into earth point....

yep, clean up the earth points. they need a good metel to metal contact.

that'd be the first step in the dance...

Check if the groud that goes from the motor to the frame is ok . There supposed to be a wire that goes from the motor to the frame usualy near the rearsets....  

Or  if you have some of these symptoms...

http://www.ducatimonsterforum.org/index.php?topic=68621.0

I orginally pulled this bike apart 18 months ago and after the cosmetics were done (frame powder coated, wheels painted, nuts n bolts plated) I assembled the bike using a spare engine I have while the orginal engine was in the process of its rebuild.  That worked fine so I'm assuming it can't be the earth! I have a spare brand new starter motor so I might try that today (I did rebuild the old stater motor with new contacts but I may have over tighten the connecting bolt and done some damage!  ), plus while I have the alternator cover off I'll check out the sprag spring, great link Ducatigirl100 

if an earth lead contacts the frame remove all powder between the earth lead and frame.  not just the thread.

better still, piss off the stupid lead that goes from engine case to frame and just go engine to battery.  also clean the frame under the airbox mount earth point.

bare metal under any earth.

 

I have some good news....... & I have some farking terrible news!

The good news is the starter motor is fine! As I had it out and a new starter sat on the shelf I replace the starter with the NOS one.

Once everything was reassemble and with spark plugs removed it turn over beautifully and could have turned over all day.  BUT..... With spark plugs in it struggles to turn move than half to one turn! Could it be as Graymonster suggested, a tight fitting ring?

Quote from: brad black on December 18, 2014, 05:16:47 PM
if an earth lead contacts the frame remove all powder between the earth lead and frame.  not just the thread.

better still, piss off the stupid lead that goes from engine case to frame and just go engine to battery.  also clean the frame under the airbox mount earth point.

bare metal under any earth.

Absolutely as Brad says.

Does the harness still have that super-dodgy y-connector for the 12V+ lead off of the battery?

As Brad Black said, battery ground directly to engine.  You should still have a ground path from the frame to the battery to assure the rest of the electrics operate correctly.  Still not good?  Positive lead from your volt meter to the negative post on the battery, negative to clean metal on the starter, like an ear a mounting bolt goes through.  Crank engine.  more than .5 volts?  Bad ground.  Now, positive on the positive terminal negative on the starter lug.  hit the starter button.  More than .5 volts on that side?  High resistance at a connection there.

Oh, don't assume one of those three batteries must be good.  Charge and load test.

An update:

Earthing points have been filed back to bare metal, every nut, bolt & top hat washer has been cleaned and polished.  All cable ends have been cleaned and polished to a mirror like finish.

Still won't bloody start 

It's better, it turns over maybe two or three time and then the earth cable from battery to frame starts smoking! Next step, all new cables! Might be awhile now as it school holidays and I get very little garage time