My Honda NT700V, I replaced the stems with 10MM size. I put on 90/87 deg aluminum body style, so I never have to replace them cause of rubber deterioration. They have a rubber o-ring on outside base, and a nut on inside. Don't know what size the Spyder has.
~~~I purchased several valve stems very similar to what you described here, may even be identical, except the ones I bought and used looked to be made out of brass. I used them on the 1992 BMW R100 GSPD I bought in December 2014. It was a one owner bike and although the owners rode it far and wide (Dempster Hwy., the route in Canada on the eastern side…I forget the name of the road, loop. Part of it at one time the Canadian park service issued to you a mobile phone that was able to get in contact anywhere on that road to be used in the event your vehicle became disabled, as w/o being able to contact the park service for help, you would surely die from exposure, etc. that road, and I’m sure many following here knows which road I speak of, well, it was on my bucket list. I’m not too sure anymore if I could pull off that ride, even with a riding partner. Anyways, that GSPD I bought traveled it and many other far away rides. Sorry, but I digress, I wanted to mention when I changed both tires the OP had someone install tubes in both tires/rims despite this particular R100 having come from the factory with spoked wheels that could run tubeless tires, and I bought the valve stems you mentioned so I could run tubeless tires. That said and as you mentioned, a black rubber o-ring was used to seal the valve stem but, the o-ring would eventually rot and need replacing which I made sure I had several spares. I miss that old GS but I was no longer physically fit enough to keep that bike upright when it counted, IOW, I dropped it one too many times and the last time I needed help getting upright, despite the fact I lowsided it here on our homestead farm
I found a 4 pack of short metal valve stems w/nuts which also uses 2 EPDM rubber washers to seal. The seller states it will fit a normal size .453” hole. I didn’t bother to contact the seller to ask if he/she knew wether it would fit this particular application (2021 Can Am Spyder RT Limited) figuring if it doesn’t then I’ll use them next time I replace tires on one of our 2 pick-up trucks. Since I’m typing on my 12.9” iPad gen 4 tablet, I forgot how to copy and paste using the aftermarket keyboard I’m presently using but, the vendor is venystorefl. Price was $15 & change before tax (free shipping ) on eBay. They’re garunteed to withstand 200 PSI so the 17 or 18 PSI. I’ll use wont be an issue, if they ultimately fit. Obviously I’m throwing up several options of valve stems to see which will work. I have an idea the black rubber valve stems I bought in the kit from Amazon will likely fit (I’m thinking) since they’re generally for automotive wheels and likely large enough in diameter to seal, as probably being the same black rubber valve stems Mike (BLUEKNIGHT911) spoke of using on his Spyder
Best,
Jake
Reddick Fla.
It’s never too late to have a happy childhood
