replacing rear B4 shock

[Mick77]

Hey guys (and gals), I just got my B12 shock "upgrade" for my B4.  Its from a 2001 B12, is there anything I should know before I start tearing it apart tomorrow?  Seems like a pretty straightforward process from the outside.  Do I have to take the rear wheel off, or just leave it on the center stand?  I'm sure all my questions will be answered when I look at it in the daylight tomorrow, I just thought I'd check in and see.  BTW, any advice on stiffening up the front end?  I've seen those "emulator" type things, but don't know exactly how they work or if they would even help.  (front end swap is OOTQ right now unless you have one lying around for about....4 dollars!)  Thank you and good night.

[tomacGTi]

You don't have to dismount the rear wheel but make sure you have something to prop it up on the center stand because as soon as you loosen the cushion lever, it'll flop down. If you didn't have the proper chain slack set before, make sure it is now. The increase in height will cause binding on the drivetrain otherwise.

Here's how I would do it:

-Centerstand the bike and shim the back wheel up.

-Loosen the lower cushion lever bolts: dogbones and shock mount.

-Remove the RH rearset or just swing it out of the way to gain access to the upper shock bolts. It helps to have an impact driver so that you don't strip the 6mm heads. You can do the swap without but if your shock has never been removed, you'll welcome the room.

-Remove bolts and swing shock out of the way.

Installation is reverse of removal. Also, it isn't a bad idea to remove the cushion lever altogether and wash out and relube the bearings. They sit in the line of fire of the back wheel and lead a rough life.

Forks you can get away with at least 15wt oil and stiffer springs. You'll notice the damping is still sub-par though. I wouldn't even try to add much more preload as they're underdamped as it is. Best solution is still $200 for emulators, proper springs and oil. This is a band-aid on a heart attack for the time being.

Totally cheap-ass way of doing it: cutting the tightly wound coils off the springs will lead to a .95 rate. Replace the cut section with an appropriate length of PVC. This is known as the NC Rick mod. I've run this on the track with emulators and 15wt and have no complaints, it isn't ideal but it does work.

Complete removal leads to approximately .95 rate, less if less is cut off ie. leaving more of the tighter coiled spring. Make sure you leave a flat surface when you cut and also isolate the remaining coils with a wet rag if cutting with a Dremel or otherwise to preserve temper from heat.

This may leave you very underdamped so try at your own risk. Like I said, I'm doing this with emulators so I have a modicum of control.

-Randy

[Mick77]

Ugh.. ONe day I'll have a lot of money, and can buy a bike built in a recent year... EVERY nut and bolt in the rear suspension is frozen solid.  I have no access to air tools.  I'm "screwed",    Any suggestions on that?  Also, one of those pesky 6mm allen bolts on my RH perch has been stripped out by the previous owner apparently.  Nothing I've tried will bust that thing loose.  I really didnt want to do the whole tap and die thing... any "tricks"?                            

[tomacGTi]

If everything is stuck, leverage is your friend. Dismount the rear wheel to give yourself some room and soak everything you're planning on loosening in pentrating oil. You may be able to get away with just removing the hugger but if you have to really reef on something you'll welcome the space. Just make sure the bike doesn't fall down on you!

You can try to get the upper pivot bolt loose without removing the rearset assembly but you'll have less space to work. Another approach is to remove the battery box and going at it from up top.

With the newer GSXR shock, I had to remove the dogbone to space it so I needed to remove that bolt. You can probably get away without if the B12 shock will slot in without spacing out the bones.

[Mick77]

Ok, here's my update.  I'm all done.  I swear, that rear suspension had more frozen nuts than a polar bears swim meet.  I had to cut slots in one of those dinky 6mm hex screws on the rearset, then hammer/chisel it loose.  The top nut on the shock itself is now round.  On that one, I had to HAMMER a socket onto it using two extensions and then use a cheater bar reaaaaal slowly to turn it.  That part took me yesterday night and tonite.  Leverage was definitely my best friend. Everything else went as planned... except for the part when the bike fell over.    It was getting late, I was ready to be done, and the shock was all mounted with the exception of the "dogbones"... I forgot that that's pretty much all that holds the swingarm down (or up, rather) so I thought "I'll just take it off the center stand and the weight will get it down far enough for me to put that bolt through.  It went down alright, ALL the way down, dragbike style, and it did it so fast it came right out of my hands.  All's well though, no scratches, dents or dings, just scuffed up pride...  (Wifey heard the noise and came out and saw)  But hey, its done.  I gained almost exactly 1".  And its stiff as a board now.  That part will have to wait for another day.  Thanks tomac for all your help on this one, I appreciate it.

Thought I'd add this (as if this weren't long enough already).  With the bike on the center stand, I used a ratchet strap on the rear wheel and subframe luggage bar things to pull the rear tire up enough for the holes in the dogbones to line up.  Super easy that way!

[tomacGTi]

Glad it worked out, sorry about the drop!

For future reference, a handheld impact (looks like a screwdriver you smack with a hammer) does wonders on stuck bolts and screws. Also with stripped allens, you can hammer a torx bit into the hole to bite into the material then use said impact screwdriver to loosen it up. The chisel technique works fine as well, although frustrating.

-Randy

[PitterB4]

Just wait until you have to try to take the rear rotor off for whatever reason!  CHRIST those were totally frozen on my B4.  Ended up using HEAT (propane plumbers torch), penetrating oil and a small pipe wrench to grip the top of the bolt.  FUN STUFF!

[mr200t]

ok so whT HOCK Cn i ue to lower the tail height cuz im short.....?

[Red01]

ok so whT HOCK Cn i ue to lower the tail height cuz im short.....?

Just get some platform boots. 

[mr200t]

ha ha ha funny red. cmon really guys. no love for short riders? lol

[Mick77]

Well, with my recent "epiphany" concerning the function of the "dogbones" that I forgot to re attatch... I'd say shorter dogbones to lower ride height... am I thinking correctly guys?  Or you could always shave the seat foam.

[Banditmax]

Longer dogbones lower the rear.....

[tomacGTi]

Just remember that changes made to the dogbone length will affect the rocker ratio on the rear shock.

You may make the shock even softer or harder than it is just because you increase/decrease the leverage ratio to actuate it.

I'm not sure where the point of diminishing returns is but you'll also compromise cornering clearance lowering the bike excessively. Try at your own risk.

[mr200t]

5'6" and a 1/2... see that "1/2" lets you know im lacking in stature

[Red01]

Just remember that changes made to the dogbone length will affect the rocker ratio on the rear shock.

You may make the shock even softer or harder than it is just because you increase/decrease the leverage ratio to actuate it.

I'm not sure where the point of diminishing returns is but you'll also compromise cornering clearance lowering the bike excessively. Try at your own risk.

This is true. Although, when I put shorter 'bones on my B12, I didn't really notice it getting stiffer. 

I'm not sure what changes in 'bone length equal a certain change in tail height on the B4, but on the B6/12, a 1/4" change in 'bone length will get you a ~1.5" change at the tail light.  Since you sit well forward of that, don't expect as much change in the pilot's seat height.