Modify Chain Guide for Larger Sprocket?

50T Rear
13T Front
112 Link Chain

Doesn't seem to be much room between the chain and the chain guide with the larger sprocket.
Should I be breaking out the grinder and notching the chain slide some?

My google foo hasn't helped much except for some bloke in Australia whom mentioned that he "modified" his chain guide to accommodate the sprocket.

Anyone running 50T Rear and having any insight?

I used a 114 link chain when I ran 13-50 gearing, everything fit fine.

Once the chain wore a bit a shortened it to 112 links.

Since you have already have the 112 link chain, shorten the guide up a 1/4 inch or so and you'll be good to go.

I've also got a 50 in the back and there are no unusual wear problems.

Dave

Thanks guys. I ended up shaving a little over a quarter of an inch of my chaine guide. Did a turkey run this weekend and all seems well. Love the 50t on the back!

Yes, the 50t rear really makes 6th gear useful---even in hill country. The next item I would like (especially for rocky trails) is a Rekluse autoclutch. The one on my Husqvarna works great.

Dave

I recently switched to 13/51 with 112 link chain and love it for technical riding in the Idaho mountains.  Previously I struggled with the bike stalling out at the slow speeds required for tight and/or rocky trail riding.  Now it's a mountain goat.  In 6th gear on pavement I'm running ~65 MPH at 8000 RPM, rather than 75 MPH with stock gearing.  But that highway stuff is just to connect dirt roads and trails for me anyway.

Clearance for the chain at the lower chain guide is tight but I didn't have to remove any of the guide material to make it work.  I've got about 100 miles of trail riding since installing the bigger sprocket and there's no sign of unusual wearing on the guide.  I did have to modify the rear bracket for the upper chain foot guard to raise the guard high enough for the chain to clear it. You can see it in the image below.

Regarding Rekluse clutches for this bike, I looked into that a bit when I bought the bike last winter.  It seems that the Rekluse auto clutches draw some power from the bike to operate, and it's especially noticeable at lower RPMs.  Several (apparently) knowledgeable folks have opined that WR250R horsepower will suffer noticeably if used in combination with a Rekluse clutch.  They believe the Rekluse system is better suited for 450cc and larger bikes.