I bought the solenoid Yamiya sell. I gave that to my CB750 K2.
It did not last long.
During a longer ride starter suddenly did not want to run after a coffee break. It had worked 1 hour earlier.
Not many starts during 3 months.
I had earlier bought a much cheaper one I did not trust.
https://www.ebay.co.uk/itm/200946091392That one went in after I recrimped the bullet plugs with correct pin and socket. It work fine. I wrapped around a little vulc tape so it sit tighter in the K2 solenoid holder.
I have after that bought 3pcs of solenoids to have in stock. They need to get the connector removed and GET correct pin and socket.
https://www.ebay.co.uk/itm/142088552120I had same bad luck with Yamiya blinker relay that I could not get to work, I really looked how it should be connected at Yamiya's page, 3 connectors, only 2 to be used.
I found a cheap relay of same size for old cars locally here that worked direct.