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Submitted by: cbr99xx

Why do this?

A couple of reasons, raising the rear ride height gives you more ground clearance and increases rake.
The increased rake makes the bike turn more quickly.

I tour on my XX with Givis loaded down this, combined with a rider weight of 225 lbs, made my bike “slap-happy”. Adding rear ride height is the cure.

Why can’t I raise the rear even more to make it turn quicker still?

Be my guest… But remember that as you increase rake you reduce trail. If trail is reduced too much, instability will become an issue.

Here is how I shimmed the rear shock on my Blackbird.


Step 1) Set bike up with center stand on top of a ¾” thick piece of wood.
View attachment 8

Step 2) Remove seat.

Step 3) Unbolt two bolts at the rear of the gas tank and raise the tank. I used a screwdriver to prop up the tank, you can use the wrench in the stock tool pouch (but who wants to put that puzzle back together).
View attachment 10

Step 4) Loosen the shock mounting bolt (17mm), you will see the nut you are to loosen as soon as you raise the tank.
View attachment 15 View attachment 14

Step 5) Install shims on top of the shock mounting clevis. *
* I am using shims purchased at a local hardware store, the slot measures 3/8” and they were labeled 1/8” thick. When I stacked the two shims together I came up with 6mm.
View attachment 13 View attachment 11 View attachment 12

Step 6) Tighten shock mounting bolt (41 ft lbs).

Step 7) Bolt tank back down.

Step 8) Install seat.

Step 9) Go ride!

I should note that this drops the wheel down ¾”-1” at the axel. You will notice this the first time you put the bike up on the center stand. You will still be able to spin the rear wheel but if you are on the slightest incline the rear tire will touch down.
View attachment 9

** A 190/50 tire is mounted in the ground clearance picture, clearance for the stock 180/55 will be slightly different.

This has to be the single best mod I have ever done to a bike. The shims cost .67 each and took all of 30 minutes to install. The increased agility is amazing; my XX had the tendency to run wide at exit (in part due to my Corbin seat allowing me to sit further back from the bars)... Now, with more weight over the front, this has gone away. I believe that when the proper 180/55 tire is installed on the rear, handling will be even better.
 

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Slinger5150
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I did the same thing, only I had to remove the resorvoir bolt to let the shock drop down enough to clear the frame. Also, I used steel washers from a hardware store instead of shims. This is the reason for needing to drop the bolt all the way through the frame. I just felt better with washers, knowing they can't go anywhere.
 

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Thanks guys. My techo installed a 6mm washer and the bike is transformed. With weight on the back (Givi type topbox and throw over saddle bags - total weight 60+ Kg), originally the bike waggled the bars under fairly ordinary acceleration. Now she just drives hard, unless I try too hard then the bars give a warning wiggle and settle down. Put in RaceTech 1.0 kg front springs at the same time. 60 kmh signed corners are despatched at 2X posted speed advisory without any effort. Nearly as good as my ex 954 'Blade. On worn OEM Bridgestones. Have since fitted Metzler Sportec M3 F/R - even better - now any wiggles are from the shortened trail. Haven't worked out what that is yet - math is p*** p***. Factory measurements from English mags say 99mm trail/25 degree rake on OEM tyres. Any way - the bike has no problem keeping up with shorter wheelbase sports bikes - combination of improved handling and much more confidence hitting the throttle more assertively. Try it - you'll like it!!!
 

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Slinger5150
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I shimmed my bird the 1st week I owned it, bike steered like a tank compared to my last bike. I used a 6mm shim, after you torque the nut down I don't see how the shims could come out.
Now I'm waiting on a set of VFR handle bars & might put on a rair of Buell Ulyssus footpegs Lower pegs, a different idea - Public Discussion Forums.
I guess the shims never came to mind. The article I read on doing this had me using washers, so I just followed what it said. I wish I had used shims, MUCH LESS EFFORT!
As for the lowering pegs, Dave on the .org site had lowering brackets machined. It uses all the factory stuff, with no mods so they can be returned to stock if need be. Should be getting them in the mail real soon. I'll keep you posted on how they work out. I have a 36" inseam, so I get a little cramped when riding 400+ miles in a day.
 

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www.blackbirdownersclub.e u
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My experience is 3 mm. I tried 6 mm but the steering didn't improve much compared to the 3 mm. The ache in the wrists though doubled by this 6 mm.

For 2 months ago I decided to install Hyperpro springs front and rear.

The difference is huge. Steady as a rock. Braking is better, steeriing is better.
The washer is a cheap and effective way to improve your BB but it is not to compare with the Hyperpro springs. It cost me 210 euro's for the springs and another 100 to mount them. They also lower your forks bij 5 mm.

I would strongly recommend it to everyone. You'll be surprised by the improvement. You get an new BB.
 

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Hi guy. Thanks for that input. Have used Racetech springs 1.0kg. They have tightened up the front considerably. The rear shock may be 'binned' in favour of something more adjustable when it finally cries 'enough'. Will look at something like WP, Maxton, Ohlins (sigh) or Hagon. Open minded on this tho' as these brands are premium in Australia. Thought crossed my mind to use FireBlade 919 RWU fork lowers and internals to get some adjustability in the front. As an aside - have fitted Metzler Sportec M3 tyres which seem to be very good after 1000 Kms. My suspension guru's here in Perth WA recommend 38 psi (max) in the front and 40 - 42 psi rear depending on the load. Have used 36 - 37 psi in the front which always seems to run hotter that the rear. Revised geometry appears to be loading the front tyre more than standard OEM fitment. Compound has a lot to do with it too, I guess. Anyway - for those interested, the M3's seem to be doin' a fine job. :clap:
 

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Seems like a very effective mod. Is there a limit to how much you can shim it? For example, can you go 10mm?
I'm using a 7.5mm shim now. I tried the 6mm shim still didn't like the way it handled (heavy steering then bike would fall into corners when pushed a little harder thats with 35/36 or 42/42 psi tire pressures) with the 7mm shim the bike rails through the corners & is still stable at high speed.
The only problem is when the bike is on the center stand both tire are on the ground, when I push down on the bars the rear tire is slightly off the ground.
 

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Went for a very, very fast ride this Sunday gone. BB passed, equalled or beat the following: Aprilia Tuono, Moto Guzzi V11 Sports (Capo Italiano paint - lovely), MV Augusta 750 Brutale, CBR1000RR, XJR 1300. Whoa girl - 38/38 psi F/R. Head shake came back at lower pressures in rear tyre. Ideal general purpose pressures seem to be 38/40 psi F/R respectively. Regarding Rake angle at the front Slinger. The BB does steer as good or better than the bikes mentioned above - I reckon the trail makes the sensation of instability more apparent. Flip flop corners are a delight now compared to previously when the stability of the bike caused great amounts of sweat forcing the BB to turn as quickly as I like. I guess it all boils down to the types of roads we ride, the speed at which we ride them and the quickness of the steering that we want. The roads above were twisty, some very slow corners (posted 30 kmh speeds), mixed with fast, never ending corners mixed in - a scratcher's delight. Even with the head shake under hard acceleration out of any corner the BB felt stable and never felt beyond my ability to recover from rider error. 6mm washer/spacer/shim in the rear, 1 Kg springs and less airgap at the front - whatever - the BB does it for me!!! Oh - age is on the wrong side of 55. I shouldn't be doing this sort of thing - NOT!!! trying to last as long in years as the speed I travel at - BB's rock!!
 

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This headshake thing you're all talking about, is that only under super hard acceleration out of a corner (+7 and slam it)? Cuz, I haven't seen it yet and... well... don't really want to.
 

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Dania Beach ???

You must have bought the Bird from Tony ?

I live just off Hwy 84 east of 95 in River Oaks

Sorry flying out tomorrow 0600 to Las Vegas for 9 days, but will be back the weekend of the 31st. Will have to hook up for a ride.
 

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shims

i placed a 6mm shim on my rear shock and raised the bike, shortening the wheel base handles beautiful now the only problem was wasnt happy with the way centre stand was so close the rear tyre whist is up position, it also looked out of place so i removed it looks much better.
But thanks to the guys who gave the info, i ended up making my own shim from a 6mm angle bracket works well
 

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did anyone remove the centre stand when installed shims, it was a little to close to the rear wheel for me, bike looks better with out it
 

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I prefer Penske:thumb: and keep the centre stand.:twocents:
 

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i did my shock shim about 18 monts ago gott it from jaws its 6mm and noticed a differance i also had to remove coolant resivor turns great tracking is on the money
 
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