125-200cc What is up with these fuel tanks???

I wanted to up the size of my 02 cr 165 fuel tank, pn 88862, which is listed as 8.5L, so I bought the 88877 wr tank on ebay, which is supposed to be 11.2L. WELL, my trouble is, I measured the capacities side by side and they both hold the exact same amount...about 9.3L. Anyone have any experience with this? The tanks have slightly different shapes.

The WR should be significantly taller around the filler neck section. It's the tank they use on the 00-05 WR250.

Yup, I did the same thing. Bought a wr tank for my 02 cr250. Same thing. Ended up buying a used IMS off the board here.

Yes, the wr tank is taller, but doesnt hold an ounce more fuel that I can see. I am going to try the fuel tank expansion trick with the new tank, otherwise I just threw away my money. Very dissapointing and hard to understand why they would spec two tanks with same capacity like that.

As a follow up, I decided to try and expand the capacity of my wr tank using hot water and compressed air. Although I did not get all the expansion I wanted, I did manage to raise the capacity from about 9.3L to 10.6L, which is 2.8 gallons. This is still not the advertised capacity of this tank, but it's better than I had before and better than the newer bikes stock tanks.