How to solve "sprag /starter-clutch" problems

[ducatigirl100]

Here's the description of symtom's /diagnosys

1-You press the start button and the engine turn 2-3 times and then stops and you ear a .... scary noise
2- the selenoid does it's"clic"
3- the startor motor gets + 12volts
4-the starter motor turns but it seams to slip......

At some point the motor will not start at all !!! You will only ear the " wwwiiiiiiii" when you press the start button...

reason : The little spring on the sprag is finish !!!!!

Prepare yourself to open the side case cover on the alternator side  

the sprag is a one way bearing roller linked to the crankshaft. when you push the starter button it rolls connecting it whit the starter gear

 but once the motor is starterd the centripical force push the bearings out so there's no contact between the starter gear and the crankshaft .... but you need a spring to keep some presure on the bearings

the reason : if there was direct contact betwen the cranksaft and the starter motor while the motor was turning... well.... the starter motor would blow up after 1 km ... !!!!!!

[ducatigirl100]

"Special Tools " :

1/2.   30mm socket
a big 1/2 ratchet / bar
Circlip tool. That open's at least 2 inch's
side cranckase puller
A gasket or gasket gooo to put the sidecase back on the bike
Hayne's manual ..... just in case...

the rest is normal tolbox tools ...  

[ducatigirl100]

Step one.....desasembly  

1-drain the oil
2-ensure the bike is in a uprigth position..... easyer to work.....  the bike stand gets in the way when you take out the side cover

To this point ,the hayne's book is really precise ... so i'll wil not explain in details how tu get the side cover off

But at some point you will be at this step.......




Don't forget to take note of the timing mark for the pick ups  for reasembly !!!


Unbolt the pick ups.   / 10mm nut

[ducatigirl100]

Now you have to take out the 30mm bolt that hold's the flywheel on the cranksaft

Use a bar or a "really big" screwdriver in the hole of the cam gear to prevent the motor from tuning while you uncrew the 30mm nut.....


go easy at this step....be carefull not to damage anyting !



Result :  


keep track of the way the magneto was initialy ... but if you wana know the side that as the "ducati" on it goe's face to the motor side

[ducatigirl100]

Now you have the flywheel in you hands !!!!  Yepp! I know.... it's heavy ... time to get the Nichol's flywheel you've been dreaming about  for the last 5 years !!

Now pull the gear at the back of the flywheel...  pay attention to the roller bering inside the gear keep track of the way it was.... to not reasemble it on the wrong side

 

[ducatigirl100]

Take out the circlip that old's the sprag in place..... yepp it's an excuse to get a brand new circlip tool set  

[ducatigirl100]

Carfully take out the sprag




Take note of the way the sprag turns for reasembly

[ducatigirl100]

Take out the spring from the sprag ( I like saying that  )......  carefull .....noting will hold the bearings in place after the spring is out

[ducatigirl100]

Here's the  problem

the spring is stretch and as lost it's capacity to old the bearings in place in the sprag...

 It's all colapse on itself

[ducatigirl100]

So there's 3 solutions for this

1- Get a new sprag whit the spring   150 / 200 $

2- cut 1/4 inch of the spring .... temporary solution ... I've tried that and ...well... destroyed the fragile spring  

3-   Get the  NAPA  parts  oil seal number  :  CR 19778      and bum out the spring from it as a replacement part !!  11$

I'll try solution number 3 and keep an update this week....

[silas]

"Like".  Great write up!

[ducatigirl100]

"Like".  Great write up!

tank's   there is a small part still to come

[ducpainter]

Nice write up.

Just a note for those removing the side cover on a newer bike with a timing sensor.

If you add a gasket you will need to check the timing sensor distance from the wheel that triggers it. It may not be possible to get it to the recommended distance.

[ducatigirl100]

So I've got the CR 19778 today     so here what it looks like ... now you just have to bum out the spring from it



old vs new  .
 

[ducatigirl100]

Dont forget to align   the   DOT on the flywheel whit the woodruff key

Put everyting back togetter, put some oil in the bike and "voila"

Press start

and "vroooooum"!!!