Hi,just recieved a 150 amp solenoid from Adam,who had the Aprilia Dealer at Leigh until recently.His website is Apriliarider.The difference is a much bigger kick on start up.Away for the NorthWest 200,I noticed not being on my trickle charger,a slight delay on start up.Even though a recent 13.5 amp battery is fitted and I was covering 200 miles a day.The negative side of the solenoid had been getting hot and was melting the rubber boot.So,even if you have fitted a larger battery I would still change to the new updated,higher output solenoid.That weedy 50amp is not up to it!Regards AL