Motorcycle Repair: starter drive clutch, starter clutch, yamaha virago 750

Question
I have a 92 Yamaha virago 750.  I am having a problem with the bike starting.  When you hit the start button you hear the starter run and the solenoid moves but the engine doesn't turn over.  You can hit the start button again like three times then the engine will turn over and the bike will start.  I have a new battery in the bike and inspected the wires.  I have taken the crankcase cover off and inspected the operation of the solenoid and drive lever.  It looks fine as do the starter wheel, idler gear set, idler gear.  I bought the starter to a repair facility and they went through it and cleaned it and told me everything was within specifications.  The starter clutch splines look fine as do the inner bushing.  How can I test the starter clutch to be sure it is ok?  Do you have other ideas of things I can check while I have the crankcase cover off?  Any help would be greatly appreciated.

Answer
Victor,

The Virago had some starter design problems on
the 750 models up to about 1985.
They redesigned the whole thing and added a
starter drive clutch.

The early models did not have this one-way clutch.
If the gears are not worn and the starter
and solenoid lever are engaging okay then the
problem is likely the drive clutch slipping.

It is a one-way clutch that turns one way
and holds the other way. If it slips
backwards then the motor will not turn over.

It is hard to check by hand as it might feel like
it is holding and then when power is applied
it will slip anyway.

It is #18 in this picture:
http://www.viragoownersclub.org/Dr%20Piston/Images/starter_image_2.jpg

The picture also has a diagram using a relay to improve
the voltage to the solenoid as low voltage
can prevent the solenoid from engaging well.

You can try a more direct battery connection
to the solenoid if you suspect it is not engaging
the gear well but if it slips most of the time
and grabs occasionally I suspect the drive clutch
is worn out.

Here is another good link to starter info:
http://www.viragoownersclub.org/Dr%20Piston/84_and_up_starters.htm

Luck!
Wayne S
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