Front Rotor - RD350B

[oxford]

350guy, I thought about it last night after I posted, I might be giving you wrong info on what you are wanting to do.

 The TX lowers are the forks to get dual disc on a RD but I think you are going to have the same speedo problem as with flipping factory forks around for the caliper in the back.  You will just gain the caliper on the same side as stock.  Sorry for the confusion.

[SoCal250]

TX500 forks have caliper mounting lugs on both legs and the full assembly is roughly 1.5" longer than RD forks. The right side lower is the same part on the TX and RD. Lowers are interchangeable.
A left fork slider from a '73-74 TX500 can be swapped in to replace your OE RD350 lower. That will give you a provision for mounting a caliper on the other side (in front of the leg). As mentioned above if you swap sides with lowers to move the caliper behind the fork you're going to lose the speedo drive function.

371-23126-60-00  FORK TUBE, LOWER LEFT    TX500, TX500A, XS500B
351-23136-50-00  FORK TUBE, LOWER RIGHT  RD350, RD250B, TX500, TX500A, XS500B

[Dvsrd]

AFAIK, the only 34 mm Yamaha forks with the calipers behind the sliders are 1976 XS650C and pre-Daytona RD400.
The XS sliders are a bit longer than RD sliders, and also have larger OD.
The RD400 sliders are also different from the 350 ones,in the top end/ seal area. So best replaced as a pair.

[350GUY]

350guy, I thought about it last night after I posted, I might be giving you wrong info on what you are wanting to do.

 The TX lowers are the forks to get dual disc on a RD but I think you are going to have the same speedo problem as with flipping factory forks around for the caliper in the back.  You will just gain the caliper on the same side as stock.  Sorry for the confusion.

Thank you Oxford guy for clarifying, know that it is appreciated.

[350GUY]

TX500 forks have caliper mounting lugs on both legs and the full assembly is roughly 1.5" longer than RD forks. The right side lower is the same part on the TX and RD. Lowers are interchangeable.
A left fork slider from a '73-74 TX500 can be swapped in to replace your OE RD350 lower. That will give you a provision for mounting a caliper on the other side (in front of the leg). As mentioned above if you swap sides with lowers to move the caliper behind the fork you're going to lose the speedo drive function.

371-23126-60-00  FORK TUBE, LOWER LEFT    TX500, TX500A, XS500B
351-23136-50-00  FORK TUBE, LOWER RIGHT  RD350, RD250B, TX500, TX500A, XS500B

Thank you very much SoCal for sharing these deets, this is extremly hepful.