Dumb question maybe ?


XS650 Addict
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Looking at the drum front brake of my XS1B, and not actually having an owners handbook yet, I'm wondering why Yamaha designed in an air scoop, but then blocked the intake with a tin cover.
Likewise, they put six vent holes in the oppersite side of the drum, then plugged them with rubber bungs.
I presume the vents were only intended for racing or high speed highway riding.
BSA Triumph on the other hand, produced two generations of TLS brakes with air scoops and exit vents.
They never blocked up their vents, and I've never heard any complaints about brakes getting waterlogged in bad weather.
Just seems not to make any sense.
Were Yamaha afraid of being sued for something maybe ?
I've noticed that on the German market SR500 drums, the rubber bungs are "dummies" designed not to be removed.
Good point on the tin cover on the air scoop. Doesn't make sense.
The six rubber plugs on the other side may have been an aesthetic decision. The drum would look pretty boring without them. And that may explain the dummy plugs on the SR500s.