First ride after fork rebuild: brake funkiness + fork oil question

Steve Northrop blackgpz at
Thu Jul 3 11:38:39 PDT 2008

     It's the calipers on the slide pins. Could be a little looseness of the 
pads in the calipers as well. The DP pads in the Daytona "clunk" 
considerably more than the EBC pads in the GPZ. SBS pads were the best in 
the GPZ, because I only got a little "click" which was the calipers against 
the floating pins. Another cause, though not common, is loose buttons 
between the rotor and rotor hub.

Steve in Western NY
'96 GPZ1100
'02 Daytona 955i
'08 KLR 650
"You Can't Fix Stupid", Ron White

----- Original Message ----- 
From: "1KPerDay" <1kperday at>
To: "GPZ LIST" <gpzlist at>
Sent: Thursday, July 03, 2008 12:56 PM
Subject: First ride after fork rebuild: brake funkiness + fork oil question

>I just rebuilt my GPz1100's forks and took it for its first shakedown
> ride this morning. When I apply the brakes, EVERY time I apply the
> brakes hard or soft, there's a "thunk" I can feel through the bars.
> The harder the braking, the harder the thunk. At moderate to hard
> braking there's another thunk when I let off the brakes. At first I
> thought it was the forks because the first big hit was into a gutter
> merging onto a street, but now I think it was because I applied the
> brakes at that time.
> I did torque everything to spec, and even pulled over to make sure the
> caliper bolts were tight. It feels like it does when they're loose.
> What else could be thunking around up there? Pads inside the calipers?
> something else? I'm at a loss.
> P.S. I'm 99% sure it's the brakes and not the suspension; even on the
> tiniest 2% braking I can feel the thunk and repeat it over and over at
> any speed, as long as the front wheel is turning. At a stop it goes
> thunk once but doesn't repeat until I move the wheel.
> Stock fork oil (I believe) is 10W-30. I put 10W fork oil in with a bit
> of 15W (which was recommended by the list.... in fact most said use
> straight 15W but I was happy with how the stock fork worked, and by
> the time I had "half" of the 10W in--by my estimation--it was already
> pretty much full). Anyway it feels much more active now, and bottoms
> much more easily than I remember 4 months ago when I took it apart.
> Am I right in thinking that 10W30 is 10W when cold and 30W when hot?
> If so, wouldn't it make sense that the "actual" riding weight of the
> fork oil when warm/hot would be somewhere between 10W and 30W? I liked
> how the stock oil behaved... I'm not sure I like the new stuff. Any
> input? Would crud/water/breakdown over the past 23K miles make the oil
> feel thicker or thinner? Is that even possible to predict?
> -- 
> Utah Jeff
> '96 SheePz1100 

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