Maybe somebody has a TBR7 has done this will post up their solutions. But I am thinking that front tire maybe a 90/90 19 which is a problem size tire to fit and find dual sport or dirt sizes. The real issue may be the rim width, if it is 1.85 inch it is not recommended for 100 series tires. A 90/100 19 would fit.
The first number in size is the tire width so 100mm wide. A 90 series tire is 90mm wide. If the TBR7 has a 1.85 inch wide rim it is not recommended for a 100mm tire but I think many put it on knowingly or not.
The X-pect has the same problem. I got my understanding from this post.
http://www.chinariders.net/showpost....05&postcount=9