Pulsing Disc Brake?

I've noticed that the front disc brake on my bike acts as if the disc has a
slick portion on it. It feels normal at speed, but as I slow to walking
speeds and below, I can feel the front brake become more and less effective
with each rotation of the wheel. My first thought was a warped disc, but I
can feel no pulsing through the brake lever. Also, the brake is not
initially spongy as is common with a warped rotor (the warp knocks the brake
caliper piston back). I broke in this bike very carefully, and did not even
notice this for the first 2,000 miles, as I was braking gently. It is most
noticeable with harder braking at very slow speeds. Any ideas will be
appreciated!
thanks, Mike

 

Mike ....
My first thought was silicon. Did you use any kinda spray, or wax, maybe
somthin' you used to clean the bike with?

First off, pull the caliper(s), and yank the pads. Deglaze 'em, then
clean 'em real good with lacquer thinner, and do the same to the
rotor(s) Maybe somthin' from the road mighta got up in there, but it
probly came (unintentionally) from you....that's if there ain't somthin'
wrong with either pads and/or rotor(s)

Ck to see (online) or at the local stealer if that "problem" isn't
common to that bike, and/or what can be done, or if there's a campaign
(we call it recall) on that bike.

BTW, it would help to no end if we knew WTF the bike was, it's year and
mileage.

That's unless you wanna keep it a secret!!
<bfg>






mtm

'95 750 Nighthawk (big red)
'95 Helix (little red)

 

mtm,
thanks for the ideas - I haven't used any chemicals around the brake, but
the manufacturer/dealer might have - I'll try brake cleaner on the
rotor/pads - that would fit the symptoms.
I didn't mention the model, because it isn't a common one (and I'm hesitant
to mention Harley or worse, Harley Clone on this newsgroup!). It is a 2002
Big Dog prosport (kind of a Harley clone on steroids), and the brake is a PM
(Performance Machine) 4 piston caliper with a PM stainless steel rotor. The
manufacturer had not heard of the problem, but I'll email PM to see if they
have.
thanks, Mike
BTW, I've owned a lot of bikes, and this one is a blast - hotrod motor,
limited, but good suspension, and actually handles well (I live in Kansas,
so I don't require the canyon carver type of handling - for the one curve we
have, I think the bike does well!)

 

Mike ....
I'd be gettin' on the horn to PM on those brakes ASAP if the 'cleaning'
doesn't work. What I hear is they're pretty good about 'stuff', but
that's not from my own 'personal' experiance. You'll find out quick
enough how they stand on "takin' care of business" after you talk to
'em.

Just remember one thing, the "person" you talk to on the phone may not
be a "Tech" expert, so don't be afraid to Ask for one, IF you get
doubletalk. That's the way it is.
The guys who "Know" don't usually answer the phones. Good Luck.






mtm

'95 750 Nighthawk (big red)
'95 Helix (little red)

 

You could certainly clean the disk with brake cleaner and perhaps sand
it very lightly to break any glaze.

It's also possible that the disk is either warped or cocked slightly,
possibly as the result of banging it on something in a drop or when
changing a tire.

You didn't mention if it was a floating disk or not.

Last go around I had with mine, I found the whole disk was slightly
cocked. I was able to shim between the carrier plate and the wheel
to get rid of the wobble and got a considerable improvement in the
braking.

Secure a dial gauge or some kind of a scribe to the fork leg or
put a strong light behind the pads and squint at the clearance
to get an idea of whether or not the disk is true.