I decided to spend this weekend putting the black rear fender on the Yamaha WR450. I've been putting it off because I knew the fender wasn't going to fit right because it was made for a Yamaha YZ450 and I knew there was going to be some modifications that would have to be made to make it work.
I wish I could've found a black rear fender that would bolt right on but I didn't have any luck locating one. So I'm going to spend about 2 days off and on putting on a rear fender that could probably be done in less than an hour if it were made for my bike.
The first thing I had to do was find a way to put the taillight on the YZ fender. And that's not hard to do but it's kind of hard to make it pretty when you're done. The WR fender has plastic bosses the taillight screws go into, the YZ fender doesn't so the bolts have to go through the fender itself.
Another problem is the little plastic fender extension mounting holes don't match up, the fix for that was fairly easy I just use one original hole and drilled a new hole for a small nut and bolt to hold the fender extension.
A more difficult problem has been that there is a metal plate bolted to the WR fender that holds the battery and some electronic gadgets. I guess the YZ does not have this plate because the four mounting holes in the WR fender are missing on the YZ fender. But worse is the YZ fender is a completely different shape where that plate is supposed to bolt in so making it work involves more than just drilling four new holes.
While I had the bike apart I took the opportunity to install a Shorai lithium iron battery. This battery has almost twice the power of the original battery, is almost half the size, and saves a lot of weight. I weighed both batteries on my digital postal scales and the factory battery weighed 4 lbs. 8 oz. while the Shorai battery weighed 1 lb. 9 oz. I've been told that the lithium iron batteries don't catch fire and explode like the older lithium ion batteries and I sure hope they're right because I'm going to be sitting on it.
If everything works out tomorrow and I'm able to find the metric bolts that I need to finish the job I will post some pictures showing what it all looks like.