Went out to do some maintenance on the bike while it was decent out and before snowfall. Replaced the air filter and charged the battery and got to work replacing spark plugs after ensuring the bike starts up. I replaced 3/4 plugs without any issues, til I got to the last plug (Left Front). Got the old plug out, new plug felt like it was going in... aaaaaand proceeded to cross-thread or mess up the threads on the head side. Spark plug threads survived, but the threads inside won't take the spark plug. I was able to get it in and the bike starts without a misfire, but now I'll need to re-thread inside.

What's the thread pitch/size of those plugs? Is there a tool to make it easier to get in there and clean those threads? I have a thread kit, however, it's fairly shallow and I'm not sure it'll reach all the way in. If I'm SOL, any idea how much a shop would normally charge to clean the threads? The last thing I'd want to do is end up replacing that head.