Does this cross-brace exist on the standard frame in addition to the special frame?

[CoconutPete]

To cut or not to cut....

I'm mocking up the bracket in the rear of the frame for my Counterbalance Cycles seat.

My frame is a Special. The bracket I have the arrow pointing to is causing the seat not to sit 100% flush to the frame. It's close, but it's not 100%.

Searching random products and threads often refers to "the cross brace on the special frame".

So... I started am image search, but the answer was elusive.

Does anyone know if this brace existed on both frames? I'm struggling with whether or not to cut it out.

 

[CoconutPete]

This is the bracket going in the back of the frame.

 

[pekka]

Hello Pete,

I think Yamaha added that brace to the later frames to strengthen the rear end. I know that the early (72 - 73?) model did not have that brace and the frames were said to be very flexy.

Your rear wheel is probably going to hit the bracket you are planning to use. And if the seat has flat base the tire will hit the seat too (I know, I tried... )

Pekka

 

[nj1639]

The space you're showing....
On the Special is about 6 7/8" +/-
On the Standard is 7" +/-

There's a short bend on the Special frames that the Standards don't have which may be the reason for the difference in that space.
Note that the measurements are close here due to the rear fender being in the way for a flush measure.

And yeah to what Pekka said on the tire......

 

[scott s]

Here's a picture of my bike under construction. It was a '75 and the brace did not interfere.

 

[nj1639]

I'll add that brace is equally distant back from the rear tank mount on both models, standard and special, but then again about 1/8" narrower from rail to rail on the special, measured at the rear of that brace.

 

[CoconutPete]

OK, seems the brace as a whole isn't necessarily something only on the Special frame.

This seat has been used on plenty of builds - I'm confident it will work. The bracket will only sit down roughly 1/4" from the bottom of the seat. If the rear is going in any direction in the future, it's up so I think i'll be fine with clearance, but will be checking of course.