Wanted: DFW area Tech [Issues with Decel popping]

Makes sense what 2WDW is saying. I remember early on, people were using R1 blockoff plates and turns out, you need FZ/MT 10 specific blockoff plates.

Here's what I would do. Take the bike to someone and have them change the spark plugs/air filter. On the way to the spark plugs, tell them to check out the blockoff plates to make sure they are correct and installed properly. If not, try to find a place you can order from quickly so he can leave the bike taken apart and then install the correct blockoff plates when they come in. I couldn't even see my mechanic charging me extra for this. He'd might frown about having to keep the bike in the shop for a couple days depending how busy.

Also, there's an additional hose fitting that needs to be plugged. FZ/Mt-10 specific block off plates usually come with this rubber nipple. 

Or just buy the correct blockoff plates and prepare to return them.

This way, at least if it turns out not to be the blockoff plates, you didn't lose the labor cost on nothing. You got your spark plugs done which are probably overdue or near due for replacement if it's a used bike and has been ridden past a few oil changes.

I appreciate the input.... The bike is a 2018, but only has 1200 miles on it. Practically new... My guess is he sold it because it's so obnoxious riding around town.... He did not have the DB Killer in and it was even worse. Once I added it back, it did calm down slightly; muffled the sonic boom coming from the muffler, somewhat... Out of curiosity, what type of mechanics are you guys using on these bikes? Track day/racing techs, or more Yamaha specific? I have used the Ducati techs in the past and they knew their stuff, but don't think they mess with any other brands...

I had my 2017 FJ 09 flashed by Vcyclenut and it was perfect. I had my 2019 MT 10 flashed by him also. Again perfect. I removed O2 sensors, exup valve decat and did aftermarket exhaust on both. On both bikes he notes that to get rid of popping take a wad of electrical tape and plug hole in airbox. Never saw a reason to do anything else. It works like a charm. 16,000 miles on my MT 10 and it's as sweet as can be. He charges $200 for a flash and addresses a ton of stuff. He will also turn around your ECU the same day if he gets it early in the day. I had both mine back in 4 days. He's been doing these forever and it is highly developed so you're not getting a one off experiment where someone has to figure it out from scratch. Not as well known on this forum due to smallish audience but very well known on others. He's also available to answer questions and generous with time. He's also very active on the MT 09 forum as he actually likes to ride motorcycles and chat about them.