Why would my yamaha 450 die when I put it in reverse, it runs good going forward.

Does it have a "mow in reverse" switch/setting? My Craftsman does and if it isnt set then the mower dies if trying to go in reverse with blades engaged.

Check gears are not fighting each other. Like still in reverse and a forward gear as well.

I take help from online websites that have this service like helping in repair some like reliable-store have instant help.. others are a bit slow which I don't prefe r... rest is up to u.. U can also get free manual works fine .

Grizzly 125 stalls in reverse - Yamaha Grizzly ATV Forum

www.grizzlycentral.com > ... > Grizzly Engine & Transmission
Oct 18, 2013 - 13 posts My dad just bought a 125 and it stalls the instant u pit it in reverse. ... electrical sensor that will kill the engine if the brake isnt depressed when u go into reverse. so now i need to ..... yamaha grizzly 125 dies when put in reverse.

must be a selector issue, you probably need to partially disassemble and check. The selector is probably the issue.
I would have to be certain the problem was sorted before I let a young'un on it incase it did something unpredicteable and caused harm

GOOD LUCK

see this link... should fix the problem
02 03 Reverse OR

Hi Bobbie, you have a bad centrifugal clutch. It will have to be replaced before it will go forward.

MAKE SURE THAT FORWARD AND REVERSE ARE FULLY ENGAGEING AND DISENGAGING

You got to take the chain case cover off and check the chain. Chould be broke or stretched.