Bought a new battery for testing and a new solonoid to see if that changes it.
Sprayed some things down with deoxit and will do some ground checks.
First some common sense, if it started with a jump, it isn't the solenoid. I assume you used the pin #2 to #3 headlight relay mod for the Polaris, cut pin #2 wire to harness and taped. The instant the start relay pulls in and powers the positive to the start solenoid
the headlight relay will drop outduring the cranking, I highlighted solenoid because many think we have one start relay circuit, when we actually have two.
I copied a thread where I discussed this about lithium batteries, a really bad idea for a motorcycle about 3 X $$$ that of a Yuasa AGM and no real advanatage
Not getting into it in this thread, but cold and lithium just don't mix period, talk nickle metal hydride and we are talking a totally different , a big fan of the Panasonic eneloop NIMH , they can sit on the shelf for a year and still be 95% of full charge.
The problem with lithium is it doesn't have the amp/hr cranking capacity . Charge rate is determined by the battery , not the charging system. FYI I mention this in the Polaris install, it has reverse polarity protection and also short circuit /load protection, what I mean by this is , if your bttery is completely drained and you boost the bike, best to leave the booster cables on for a f minutes, as the Polaris regulator needs roughly 8.5 VDC minimum to fire.
I will go through a cycle here how I assume your present start cycle works.
#1 key on= instrument powers up, fuel pump runs for 3 seconds, headlight is on
#2 push start button= headlight goes off, solenoid clicks in and sounds like the starter is trying to turn but won't, headlight might come on the instant you release the start button , you may also hear a multitude of clicking, in that the battery voltage is pulled down to below 8 VDC and both the start relay and start solenoid drop out for less than 5 milliseconds. It speaks the lack of cranking amp capacity.
In that lithium thread there is a warning about charging below freezing, absolutely dangerous, I have experience with lithium batteries, and have experienced thermal runaway, you have a stick of dynamite on your bike, yes technology is designed to fail safe, why put a device in something that experience high heat and extreme cold at more than 3 X $$$ of lead acid??
I also stated about life of a AGM battery using the Polaris regulator in post 32 and 33 of https://www.kawasakiversys.com/forum...ng-stator.html