Rear shock a death trap on 2011?

[mfoti]

I was told by a local suspension tuner that the rear shock on the 2011 is a death trap and does not have proper damping and that eventually it is going to throw me over the handlebars. He said the only way to fix it is to replace the piston and shims in the shock because the adjustments aren't sufficient to fix the problem? he said everyone knows this and no pro will get on the bike without a total shock rebuild. I have total of 6 hours on an MX bike so i am just learning. Does this sound right? I haven't noticed any shock problems but i am just a newbie.. so maybe i am missing something. I weight 185 with gear. What do i need to do to a brand new bike to make it "right"?

[Hans Schmid]

Your local tuner is an idiot.

[mfoti]

Your local tuner is an idiot.

Thanks. That is what i was hoping to hear. It's hard enough learning how to ride. When everyone is trying to sell you service/parts and tell you its gonna fix your bike it is very frustrating.

[Hans Schmid]

For a pro, ya the suspension isn't going to be up to par as they hit things a lot harder on the track. But for an average joe, the stock suspension will do, up too a point. Eventually it will need to be rebuilt and then you have to decide if you want to do a revalve at the same time. Does revalved suspension help, yes, huge improvements can be made BUT, revalved suspension setup wrong is going to be no better then what comes stock on your bike. The only other exception for a revalve is riding a different disipline with your bike. Such of you were riding off-road, the stock valving would be set up for track riding. A revalve can make the suspension more plush.

I'm not sure on your stock spring rates but the only thing I could suggest is going up on your spring rates to support your body weight.

[grayracer513]

There are all kinds of theories on the '10-'12. The fact is that Japanese shocks in general, and YZ shocks in particular have a distinct lack of rebound response that contributes to the back end kicking up and swapping around over rough ground. This actually undercuts the stability of the front end. The stock suspension, the fork particularly, is among the best there is on the market, and for most, it needs very little improvement. However, while it's quite a way from being a "death trap", the shock could use a simple bit of rework and be quite a bit better. There is nothing wrong with the stock piston, though.

[mfoti]

If the shock has rebound issues are most riders cranking up the rebound damping adjuster? Are they running out of adjuster and having to go to new shims? I am running stock settings right now. If you adjust the rebound damping won't that affect jumping? With more rebound damping wouldn't the front dive less than stock because of slower decompression?

Edited July 30, 2012 by mfoti

[grayracer513]

The problem with cranking on the adjuster too much is that the rebound adjuster has an effect on the compression side, also. Plus, the adjusters don't really make anything softer or stiffer in the true sense. What they do is open a bleed, or bypass, passage and meter the flow through it. Some bleed is necessary to the proper action of the valve stack, and closing it off or slowing it way down doesn't always have the effect you want.

Fork dive is almost completely independent of shock rebound, and is caused by forward weight transfer under braking or deceleration for the most part. It's affected most by changes to the fork midvalve and by the front springs. What does happen at the front end with more rebound resistance is that the dynamic steering head angle runs in a shallower range through rough sections because the rear kicks up less, making the front more stable and less prone to turning and tucking as it strikes the faces of whoops and such.

[HRC]

I rode the preseason on totally stock suspension , didn't even touch the clickers either on front or rear from showroomfloor. Best stock suspension I've ridden.

But if you still have doubts, I would recommend the adjustable Devol linkarm and set the freesag at 30mm. That's what I have now and super happy. Bike feels very balanced and predictable.

But as I said, the stock suspension is really among the best setups out there .

But I can't really deny the fact the bike has a chassi and motor concept that differs from the rest, and I actually believe that the riders that can benefit the most from this bike are the riders that aren't afraid to change riding style and try to adapt to it. To those who expect bike to adapt to em, might not appreciate it as much.

[mhebert68]

MXA explains this in their rebuild AD.https://www.mx1suspension.com/reviews/review/mx1_suspension_yamaha_yz450f_fork_shock_revalve My 2012 dances around quite abit in long whoop sections. This will mostlikey b my next mod.

[Jonnoh]

In my opinion there is an issue with the rear suspension and when it heats up, it looses rebound dampening. Some people I have talked to relate this to the heat of the pipe that runs close to the shock reservoir. All I know is that when I start a ride, all is good.... Once everything is hot, the shock can turn into a pogo stick. My only solution I found is to run the rebound slower than normal at the beginning of a ride and once it heats up, it is back to normal. For those saying there is not an issue, why does Whibly run an external quick adjust for his high speed compression due to the shock fading so much? ... I think it is the excessive heat.

Bottom line is play with different settings. I'm pretty happy with mine right now, but it has taken a lot of tweaking to figure out what works for me. I even bucked the trend and ditched the pc link and think it is way better without it with a bit more sag. This thing reminds me of the linkless KTM's I have owned that are super sensitive to rear set up.

[grayracer513]

In my opinion there is an issue with the rear suspension and when it heats up, it looses rebound dampening. Some people I have talked to relate this to the heat of the pipe that runs close to the shock reservoir.

Such people are incorrect. Entirely. The shock in the '10 and later YZ450 is LESS subject to heat from the exhaust than the previous models were for two reasons. The first is that the exhaust of the newer bike is farther away from the shock at its closest point than on the older bikes, where the often ran less than a quarter inch under the reservoir (and heat rises). The second, understanding that the bike is normally in motion, is that air flows around both the shock and the pipe much more freely than in previous models. Note also that the header is mostly located behind the shock, down farther in the normal air stream. Convected heat is simply not the issue. The air around the shock isn't still enough nor moving in the right direction to be an effective enough way to move heat across such a large gap for it to become problematic.

Shocks heat their own oil, and the fault with one that fades excessively is that it uses an inferior oil or that it isn't valved correctly to behave itself at realistic operating temperatures. KYB's as delivered on most late Japanese MX bikes are pretty commonly short of rebound damping anyway.

[mhebert68]

While I do notice a hot seat on long or tough rides, I agree that its not the exhaust that plagues the shock. Its definately a stroke issue. after 45 hrs its my bigest complaint with the bike. I just cant charge the whoops.

[galligar]

45HRS. on your shock or forks is too long, your shock needs oil change as well as your forks or more, sorry 20hrs. and my shock starts feeling bad,and I'm 57.

[mhebert68]

45HRS. on your shock or forks is too long, your shock needs oil change as well as your forks or more, sorry 20hrs. and my shock starts feeling bad,and I'm 57.

I changed the oil. its not a miantenance issue.

[Jonnoh]

Gray- I've got a coffee can size expansion chamber on my fmf 4.1 w/ powerbomb sitting right next to my shock... Wonder if certain pipes can cause more heat and quicker fade?

[grayracer513]

Maybe, but I still give very little credence to the idea that the exhaust heat is a problem. If you think it is in your case, whip up a temporary heat shield of some sort. I doubt you'll see a difference.

[MR.SPEED]

nothing wrong with the shocks on yz450f's if that's what you ride, i have read all the reviews i could find before i decided to buy my current bike and i heard nothing about the shock being a "death trap".

[Stu2]

My 11' 450 is probly the best handeling bike ive ever had, sure i have done work to it but anybike would need some as I am around 103kg,

Wrt the shock, I have increased rebound, and changed compression slightly for woods racing and it is simply sublime,

I had an Ohlins Ttx shock on my yz 250 and the Kyb feels better