rupaulpierce said:
So lemme get this straight... XR100 forks are a bolt on for the post-1980 CB125 triple tree?
They are for 1980 and up.
The XR100 forks are 27mm in diameter, so they'll go right into the triple tree. To double check make sure you have the clamp-type upper and lower triple (pictures to come later). The XR100 also has a 12mm axle so you can reuse your CB125S axle and castle nut. The spacers seem to fit very well with no modification. Lastly, the XR100 has a front drum brake so the CB125S front drum fits in quite nicely.
However, there are a few things to note about the XR100 forks:
1. You will not have a front fender.
2. They are about an inch longer.
3. They have a leading axle so the wheelbase will be slightly longer.
4. You'll have a bit more front end travel
5. I was recommended by a guy who does nothing but dirt bike suspensions to use 30W fork oil for road use. Also, the XR100 forks only need about 3oz each so a quart bottle of fork oil will be more than enough.
I have a hunch that the XR100 fork springs will fit right into the CB125S forks. I'll verify this when I get home from work.
I've also been doing some preliminary research and it seems up to 31mm forks are possible based on the triple trees which accept the same size steering stem bearing as the CB125S. It's unclear as to whether or not the steering stem itself would be the right length.