Tapered bearing for motorcycle project

[carsonmx114]

Hello,
I'm in need of a tapered roller bearing for a motorcycle project I'm working on. I'm in the process of making a roadrace bike out of a 450cc dirtbike. Part of the project is to mount a sportbike front end on my dirtbike frame. The dirtbike frame uses tapered roller bearings. The outer race on the dirtbike frame is 52mm top and bottom. The steering stem for the sportbike front end needs a bearing with a 31mm inside diameter on the bottom and a 30mm i.d. on the top. I was lucky in that the dirtbike uses a 30mm i.d. on the bottom so I can simply use the bottom bearing on the top now but I can't find a 31mm bearing for the bottom anywhere. Can anyone help me find a 52mm X 31mm X 12mm tapered roller bearing?
Thanks!

 

[diskullman]

You can get a bearing opened up to 31 mm, but this is not a great idea. It would be more sensible to turn the shaft down 1 mm because the bearing is a wearing item.

Russell Giuliano

 

[sreid]

Can you find a bearing with a larger bore and bush up the shaft size?

 

[carsonmx114]

Thanks guys, I pressed the steering stem out of the triple tree today and it's going to the machine shop tommorrow to be turned down 1mm.
Lee.

 

[Tmoose]

Grinding rather than turning is often needed to make a really nice bearing seat on a shaft.