Ooh! sounds worse than I thought. Usually the plugs will have a very slight leak if any. I’d pull ’em and see what’s up.
What year is the cylinder? If it does need new plugs, you can get the o-ringed type from Swedetech (depending on cylinder year). If the cylinder is modified, you’ll probably need to reshape the new plugs to match. Hope you don’t have to go down that road though.