cracked

Hey all! My wife's shee is nearly stock with very few hours on it. The only change is the air filter with carb adjustments to match. Plugs check out perfect..... Problem is at idle through low RPM it misses. It starts fine and seems to run fine and then misses, runs fine again, then misses, etc... ding, ding, ding, ding, lag, ding, ding, ding, ding, lag. It does better once it warms up but it's still not right. Thinking back, it started doing this after washing it near the end of last season so I was thinking water in stator or something. But, it's still doing it now so I wouldn't think it would still be doing it unless the water caused some rust. Any Ideas? Thanks!!

I saw this same thing when I googled it... That and a bunch of other back and forth conflicting reports on what the difference is and if it's ok as a premix. I'm thinking that my bikes are stock and close to stock and that it should be ok. I was just checking if anyone on here had any experience with it. Thanks all!

The wife was being helpful and stopped by the shop to pick up some oil. She picked up 2S instead of 2R. I know 2S is supposed to be for engines with an oil injector but is there really any difference? Maybe the 2S is a little thinner to go through the injector easier.... I dunno.... Just for sh!ts and giggles... Say someone had a Blaster and ran the 2s in the injector system and then blocked the system off and had to premix. Wouldn't the 2S being used as a premix have the same result as before?