Rear Shock Mod
10-04-2007, 11:06 AM
#1
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SuperSport
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Join Date: Aug 2007
Location: Eagle, ID.
Posts: 599
Rear Shock Mod
I swapped out my stock shock with Redman and in return I got a stock shock that has an Eibach spring and the nitrogen reservoir has been fitted with a Schrader valve to refilled the gas.
I have also seen the mod listed on the Internet, but cannot locate the link.
Anyone know someone that has had this done and if so what is the volume of gas needed to refill the reservior?
Thanks.
I have also seen the mod listed on the Internet, but cannot locate the link.
Anyone know someone that has had this done and if so what is the volume of gas needed to refill the reservior?
Thanks.
10-04-2007, 01:26 PM
#2
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MotoGP
Join Date: Aug 2007
Location: Lake View Terrace, CA
Posts: 5,942
I swapped out my stock shock with Redman and in return I got a stock shock that has an Eibach spring and the nitrogen reservoir has been fitted with a Schrader valve to refilled the gas.
I have also seen the mod listed on the Internet, but cannot locate the link.
Anyone know someone that has had this done and if so what is the volume of gas needed to refill the reservior?
Thanks.
I have also seen the mod listed on the Internet, but cannot locate the link.
Anyone know someone that has had this done and if so what is the volume of gas needed to refill the reservior?
Thanks.
10-04-2007, 09:39 PM
#3
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World Champion
Join Date: Dec 2004
Location: Fulton, MO
Posts: 105,287
Usually it's like 250psi and it must be nitrogen, but you will need a special fitting to accomplish this. The fitting allows you to pressurize the bladder and close the schrader while it's under pressure. I recommend a suspension shop in your state.
10-06-2007, 06:27 PM
#5
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SuperBike
Join Date: Jan 2007
Posts: 2,116
How much does 1 mm of added shock length
equate to in ride height increase with the stock linkage? I tried about 5mm on my Penske from its minimum length & it was way too much. I just backed it down to maybe 1mm from full short (PITA BTW). I also have the fork tubes raised about 4.5 mm up the triple clamps. Not sure (its been 9 years) what the OD/profile of the Conti Road Attack Rear & Sport Attack front are compared to the OEM rubber.
10-07-2007, 07:57 PM
#6
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Superstock
Join Date: Jul 2007
Posts: 387
thanks for chiming in Skokievtr, I have a new Wilbers shock on the rear and although I ordered stock height...when I installed it I left in place the two washers that jacked it up about 7or8 mms. After riding it for two weeks now....I think I'll go in and remove one for starters and maybe both later. The new spring is a bit stiff for my taste and with the washers...the *** end of my bike is way up there. I need to properly check sag first and see what's up.
It's a long process but once you get your bike dialed in to your taste....YEEHAWW...it becomes an extension of your mind and you fly!
It's a long process but once you get your bike dialed in to your taste....YEEHAWW...it becomes an extension of your mind and you fly!
10-08-2007, 07:48 PM
#9
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SuperBike
Join Date: Jan 2007
Posts: 2,116
I agree
I just don't know how the shock got shorter. OA length is 13-5/8" eye-to-eye (though I will recheck). The linkage is right. What OA length are you at, excluding any shims added between the OEM upper mount & frame? There is no recess in the frame cross member for the mount toslip into, so where did the length go???
10-08-2007, 08:14 PM
#10
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I just don't know how the shock got shorter. OA length is 13-5/8" eye-to-eye (though I will recheck). The linkage is right. What OA length are you at, excluding any shims added between the OEM upper mount & frame? There is no recess in the frame cross member for the mount toslip into, so where did the length go???
possibly you didn't get it tight when you adjusted it the last time and it spun down on you
10-10-2007, 08:31 PM
#12
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Impossible
BTW, the rear of the bike must be suspended and its easier to align the linkage bolts if the rear wheel/tire is first removed (the swingarm can then be held in place with a heavy gauge wire hooked to the subframe and the axle through the swingarm). See pics of the gantry I made to suspend the rear of the bike. These pics are over 3 years old from when I first installed the Penske 8981.
10-10-2007, 09:14 PM
#13
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In order to adjust length on a Penske, the rear linkage rocker must be disconnected from the frame, shock and link; then the locknut loosened and the bottom "eye" threaded in or out while the shaft nut is held with a one inch wrench. I use a 1" service wrench and 1" crowfoot wrench. Consequently, once everything is back together, its impossible for the length to change. I have to recheck, maybe I was too tired last adjustment.
BTW, the rear of the bike must be suspended and its easier to align the linkage bolts if the rear wheel/tire is first removed (the swingarm can then be held in place with a heavy gauge wire hooked to the subframe and the axle through the swingarm). See pics of the gantry I made to suspend the rear of the bike. These pics are over 3 years old from when I first installed the Penske 8981.
BTW, the rear of the bike must be suspended and its easier to align the linkage bolts if the rear wheel/tire is first removed (the swingarm can then be held in place with a heavy gauge wire hooked to the subframe and the axle through the swingarm). See pics of the gantry I made to suspend the rear of the bike. These pics are over 3 years old from when I first installed the Penske 8981.
There is another way to take off the rear shock.... I take a peice of a 2x4 that is around 5-6" long (it's been a while so I don't have the exact length at this time) loosen the nut on the top shock mount and put 2x4 between the sub frame and the swingarm. Tap it in place and put the bike on a swing arm stand and you're good to go.
10-10-2007, 10:01 PM
#14
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A lttle iffy
Well it's a good question on how the shock could change length.
There is another way to take off the rear shock.... I take a peice of a 2x4 that is around 5-6" long (it's been a while so I don't have the exact length at this time) loosen the nut on the top shock mount and put 2x4 between the sub frame and the swingarm. Tap it in place and put the bike on a swing arm stand and you're good to go.
There is another way to take off the rear shock.... I take a peice of a 2x4 that is around 5-6" long (it's been a while so I don't have the exact length at this time) loosen the nut on the top shock mount and put 2x4 between the sub frame and the swingarm. Tap it in place and put the bike on a swing arm stand and you're good to go.
10-10-2007, 11:02 PM
#15
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Whereas your method may work, it is not the prescribed procedure. And if the 2X4 should loosen (even if it is duct taped somehow), I shudder to think of the consequences. Secondly, your method does not provide the leaway necessary to readily remove & reassemble the linkage, particularly with a remote resevoir type shock. Some people suspend the bike from rafters when structurally adequate (and not).
As for the 2x4 commong out, yeah it could happen but it would have to move over an 1 1/2" for that to happen, so besides the fact it has never moved while I've worked on mine, you would have to really not be paying attention for it to happen. I mean one of your straps "could" break also but it really isn't likely to happen. Besides if you ever tried it you would find out how stable it really is.
I guess my real point I was tring to make is for the guys who don't have a lift and fancy gantry or rafters to work from can still do the job with no real problems. So call it iffy if you like but I prefer to do it this way if for no other reason than I don't have a bunch of straps and hardware in the way while I'm working on the bike. YMMV
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