1979 rear brake geometry question

[Guest]

I've only had 3 bikes in my life, and ridden a grand total of maybe 10 street bikes, but my gs seems to have a somewhat unique reaction to using the rear brakes-under hard riding, if I come close to the limit braking, the rear suspension almost feels like it is locking up. It does what I would expect a hardtail bike to do, with the tire skipping over road imperfections rather than letting the suspension absorb them.

It seems like this might have something to do with the brake torque arm turning the moment force from braking action into a linear force that makes the rear want to squat. Maybe it was intended to act as anti-dive? Anyway, is there any reasonable fix for this, or do all GS's do it? I haven't had the rear end apart, but it seems like relocating the brake torque arm mount to the frame rather than the swingarm wouldn't be very difficult and would fix the issue.

[tkent02]

They don't all do it. What are you using for rear shock absorbers? Maybe they are topped out hard as the weight shifts forward under braking, and it is acting as a hard tail.

Sounds scary.

[GregT]

What you describe sounds similar to too heavy a rear spring - as it's already topped out or close to it when you brake, there's no suspension travel left to accomodate the weight transfer.
Our racebike as received wanted to swap ends under hard braking due to too heavy rear springs.

Has the PO fitted aftermarket shocks and springs ?