As the title says 87 Trail Boss 250 grinding in forward gear only under acceleration... The gear selector handle goes way past the forward detent to go into gear. It doesn't do this in reverse - works great... So I think that it's the forward gear and chain... Does that sound like what it is? If so where can I get the chain and gear? Can I still get it through Polaris? How hard is it to change?

Thanks Larry

 

I`m no expert but to me it sounds like the shift fork in the tranny is wore out and needs to be replaced.