TZ or TA rear brake pedal dimensions (return spring selection)

[Dvsrd]

Lately, I have been working on converting my RD350A rear drum brake into cable operation, instead of the heavy and clunky linkages normally associated with rearsets.  Now only the pedal stop, brake light switch connection, and return spring is left to sort out.

Mead Speed in the UK have a lot of pattern parts for Yamaha race bikes, including these springs:

http://www.meadspeed.com/products/yamaha/ta125/rear-brake-pedal-spring/
http://www.meadspeed.com/products/yamaha/tz250-350/brake-spring

Before I can decide which fits best, I need to know the OD and length of the portion of the pivot piece the spring sits on/ around.

Please check if you have  TZ or TA in the garage 😁

[teazer]

That TZ spring and lever is designed to work with a rear disk.  But the TD/TR3 lever is similar and the spring is the same IIRC.

The spring locates on the footpeg mounts which are tubular on a TD or TZ.  The red frame is a TD3 fitted with a modified RD/R5 rear wheel but the spring is not fitted. The black frame is a TZ350E

Hope that helps.

[Dvsrd]

Thanks, Teazer!
I only intend to purchase the springs, not the pedal.  I have made the pedal myself, from aisi316 ss. The stationary end of the spring will have to be modified slightly, but that is no big deal!

[Dvsrd]

That TZ spring and lever is designed to work with a rear disk.  But the TD/TR3 lever is similar and the spring is the same IIRC.

The spring locates on the footpeg mounts which are tubular on a TD or TZ.  The red frame is a TD3 fitted with a modified RD/R5 rear wheel but the spring is not fitted. The black frame is a TZ350E

Hope that helps.

Could I ask you to measure the diameter of the TZ (disc brake) pedal, where the spring wraps around it?
(Just so I can spend a little quality time at the lathe, while at work on a ship for the next 10 weeks or so....)

[teazer]

Just did - you've got mail.

[Dvsrd]

Thanks!  Sitting in my hotel room (covid 19 quarantine until tomorrow). Passing time with drawing brake and shifter pivot setup :)

[Dvsrd]

Before Teazer's email and reply, I had already mailed Mead Speed regarding return spring dimensions. They replied pretty much straight away! Great service for questions regarding  10 GBP/ 13$ item :)
According to their reply, the inside diameter is 22.50 mm. Which means that the pedal "pivot housing" can be 22 mm, or even 7/8" outside diameter. Which is a pretty convenient size.
I plan on using 22 mm OD SS hydraulic tubing to start with, ideally 2.5 o 3.0 wall thickness. Then use a suitable composite bushing/bearing with 16 or 17 mm OD, and 14 or 15 mm ID. This then all slides over a top hat shaped piece, and all secured with an M8 bolt and a machined plate washer.
Once I have found a piece of suitable tubing (or round bar, if I do not find tubing), I will make a drawing, and post pics as the project progresses.