2015 WR250R keeps stalling

Hey everyone!

I'm new to the forum (and dirt bikes in general), but I've been riding and working on street bikes for the last 10+ years.

Picked up this 2015 WR250R a few days ago to explore some trails around my area. The bike has low mileage, but of course, has some issues. The biggest issue is that it keeps stalling. It starts easy, but doesn't run long and doesn't like throttle, immediately dies if I give it some throttle. When I did a test ride, it was warmed up and wasn't stalling, but it wasn't taking throttle well, it was bogging. I cleaned the gas tank (it had rust) and added some Marvel Mystery Oil, but that didn't help.

The PO told me that they drilled the baffle in the muffler to make it louder and I might have to reprogram the ECU because of that (I am not sure about that). I removed the baffle and it looks like they cut a piece inside, will take some pics later.
I might get a new exhaust for it down the line, but at the moment my primary goal is to get it running well.

Any advice is appreciated!


Here is a video of the bike running:

It's virtually impossible to completely remove rust from a tank, so my advice would be to get a new tank; IMS still makes higher capacity tanks for the WRR, so it would be prudent to get one while they're still available.

Check the fuel pump for rust contamination, and if there is any, get a new pump; in this case you may also need a new injector.

In general, it sounds like the bike was abused/neglected by the PO, so be prepared for expensive repairs.