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2014 YZ450F Revalve

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I've got a 2014 YZ450F that I'm looking for some input on revalving. I had a local tuner do 2 revalves on it already and I think all he did is take a pile of face shims out and dump a bunch more oil in (380cc!!) to make the bike into a harsh wallowy turd.

 

Rider info: 

155lbs

A class

.47 fork springs

5.5 shock spring

 

I would post up stacks the tuner set me up with but they were so far out of whack it isn't worth bothering with me measuring them. 

 

I believe keeping the stock stack arrangement would be a better move and tune from there.

Pro's of stock setup(After spring change):

-Good cornering

-Firm

-Good bottoming resistance

-Felt precise

 

Con's:

-A little bit dancy in chop

-Rear hopped around in braking chop

-Rear deflected through whoops

 

 

My thoughts:

 

Forks:

Remove 2 face shims from comp base stack

Leave Midvalve (potentially slightly stiffen rebound stack)

345cc oil

 

Shock:

Remove 3 face shims from comp stack

Potentially slightly smaller crossover in after comp face shims

Add one .40x.20 shim after the .40x.30 in rebound stack

 

Any input is appreciated  :cheers:

 

 

Thanks to MRW for the stock specs:

 

Forks

 

BCV, Bleed Valve, Comp Low Speed stack whatever you like to call it:)

 

 

14x.30(2)

12x.30

14x.11

18x.11

20x.11

22x.11(3)

 

Base Valve

 

32x.15(11)....yes,that's .15 

30x.11(3)

28x.11

26x.11

24x.11

22x.11

20x.11

18x.15  yes,.15

17x.30(3)

baseplate 

 

MV Rebound  (some more .15`s and even 20`s)

 

20x.11(2)

18x.11

11x.11

18x.15 

16x.15

14x.20

13x.20

12x.20

11x.20

10x.20

16x1.5 base plate.  1.2mm bleed holes in pistons and .25mm feeler gauge measured float.

 

MV Compression

 

20x.11(4)

17x.11(2)

12x.11

10x.20(2)

12x.30

15x.30

17x.30

Note: fork now has 500mm springs. Maybe now the plastic spring seats wont break!

 

Shock

Rebound

 

40x.20(5)

25x.10

40x.30

38x.30

36x.30

34x.30

32x.30

30x.30(2)

28x.30(2)

26x.30

Base Plate

 

Compression

 

44x.20(12)

37x.15

44x.20(2)

40x.20

38x.20

36x.20

34x.20

32x.20

30x.20

28x.20

26x.20 

25x.30

base plate

 

 

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I would use a 1.5mm bleed hole and stiffen the reb more

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Doesn't matter about the length of the springs, it's when springs bind they damage the seats. U can put 470mm long springs and spacers in that fork, I'm sure the damper rods not changed length.

If those r std stacks they totally diferant to the euro bike

If those r std stacks they totally diferant to the euro bike

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I've spent a huge amount of testing with this bike with our local pro rider, 155 pounds , running stock front springs, 250f rear spring.

He's top 10 loretta's speed - so not sure where you are in regards to that - however for him we found without a doubt (I tested extensively trackside with him) that stiffer midvalve than stock and similar to stock base valve were his favorite settings.  Drilled ICS piston and 335 cc of oil at said stiffer setting.  Very ironically - the trackside testing stemmed from him swearing it was too stiff and feeling harsh - and every time we went softer he said no improvement - I tried softer stacks with 380 oil height, stiff spring seats with 315cc oil height with same softer settng - and it was just "harsh"

 

finally after I went stiffer with the mid he fell in love with the bike.  Less float than stock, slightly stiffer stack all around.

His shock is lowered 2mm internally, .25mm thick shims in highspeed portion of stack instead of .20, with 4 less face shims than stock.

 

The rebound setting in the rear is important to make it track well, we run a fast rebound for him.

The bike is opposite most other bikes - less sag usually makes it feel more stable - pulling the forks up in the clamps(lowering the front) is a big help with stability and fixing headshake if you have any

 

 

We are running about 15mm from the very top of the fork to the top of the clam

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I've spent a huge amount of testing with this bike with our local pro rider, 155 pounds , running stock front springs, 250f rear spring.

He's top 10 loretta's speed - so not sure where you are in regards to that - however for him we found without a doubt (I tested extensively trackside with him) that stiffer midvalve than stock and similar to stock base valve were his favorite settings.  Drilled ICS piston and 335 cc of oil at said stiffer setting.  Very ironically - the trackside testing stemmed from him swearing it was too stiff and feeling harsh - and every time we went softer he said no improvement - I tried softer stacks with 380 oil height, stiff spring seats with 315cc oil height with same softer settng - and it was just "harsh"

 

finally after I went stiffer with the mid he fell in love with the bike.  Less float than stock, slightly stiffer stack all around.

His shock is lowered 2mm internally, .25mm thick shims in highspeed portion of stack instead of .20, with 4 less face shims than stock.

 

The rebound setting in the rear is important to make it track well, we run a fast rebound for him.

The bike is opposite most other bikes - less sag usually makes it feel more stable - pulling the forks up in the clamps(lowering the front) is a big help with stability and fixing headshake if you have any

 

 

We are running about 15mm from the very top of the fork to the top of the clamps

 

I appreciate the info very much!  I wish I was that quick, I'd be in the back of the pack at Loretta's if I was having a good day.

 

I looked into what the tuner did on my forks, he pulled 6 face shims out of the forks and 7 out the shock, smaller crossovers, beefed up the rebound HUGE, and put the oil up to 380cc.  Harsh packy garbage....

 

 

I've got an adjustable sub frame setup, very similar to the ones the JGR bikes have, as well as a Pro Circuit link so the rear of my bike is about 20mm lower than stock.

I might have to send some beer money your way here soon. 

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So tell me if I dumb, are these small changes(bigger/.05 thicker reb clamp and the .18x.11 in comp) enough to get anything done?

Float should come out to .2mm

 

 

MV Rebound
 

20x.11(2)

18x.11

11x.11

18x.15

16x.15

14x.20

13x.20

12x.20

11x.20

10x.20 >>>  11x.25

16x1.5 base plate.  1.2mm bleed holes in pistons

 

MV Compression

 

20x.11(4)

17x.11(2) >>> .18x.11

              >>> .17x.11

12x.11

10x.20(2)

12x.30

15x.30

17x.30

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the reb stack seems pretty strange.

Cant believe that it really uses .2 shims!!

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the reb stack seems pretty strange.

Cant believe that it really uses .2 shims!!

 

 

The new chassis needs more weight on the front, yamaha tried to accomplish this last year frame iteration with no bleed hole but suspension performance was largely degraded - not to mention yamaha is running much stiffer springs than was norm a few years back. 

 

tighten teh float to about .15 or .10 and put the base valve comp stack back to stock, then run low oil height - around 335 to start.  This should help a lot.  Don't lower the rear internally since you run the linkage.

Stiffen teh shock as well - and go back to stock rebound stack for now.  Then run the rebound clicker around 18 out.

 

Edited by harrperf
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the reb stack seems pretty strange.

Cant believe that it really uses .2 shims!!

Yeah it was hard for me to justify the .2's in the fork reb myself.

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3x20.11

18.11

11.11

18.11

16.11

14.11

12.30

That's std stack we got in Europe.

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on the 450's i've been doing, i have decreased float as well. also, i have been using a two-stage base valve. this is something i've revisited lately. i like the new yamaha platform. 

 

on the shock i've stayed around 12 face shims (comp), but the x-over was changed; using two .10 shims instead of the 37.15. i have some .25's far down in the hs. i slowed rebound a bit, in terms of the overall stack stiffness, but i run my adjuster at 18-20. the ls comp is at 10-12 and the hsc is 1.5-1.75 with sag at 108mm.

 

with my fast rider, who qualified for glen helen and thunder valley this year, i am running 1 rate stiffer shock spring than stock 6.1kg and .52 fork springs. he is 5'10 and 185lb

his prior setup was done by a major company, so the fork spring length is 470mm with national spring seats. i had to adjust my rebound valving in the forks as well. i started with the stock 2014 setup, but quickly changed it, as the bike was packing at 14 clicks out (reb). i am now running a similar stack to that of the euro config.

 

i've tested with links, and no links. the bike is better without a link from my rider feedback. 

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on the 450's i've been doing, i have decreased float as well. also, i have been using a two-stage base valve. this is something i've revisited lately. i like the new yamaha platform. 

 

on the shock i've stayed around 12 face shims (comp), but the x-over was changed; using two .10 shims instead of the 37.15. i have some .25's far down in the hs. i slowed rebound a bit, in terms of the overall stack stiffness, but i run my adjuster at 18-20. the ls comp is at 10-12 and the hsc is 1.5-1.75 with sag at 108mm.

 

with my fast rider, who qualified for glen helen and thunder valley this year, i am running 1 rate stiffer shock spring than stock 6.1kg and .52 fork springs. he is 5'10 and 185lb

his prior setup was done by a major company, so the fork spring length is 470mm with national spring seats. i had to adjust my rebound valving in the forks as well. i started with the stock 2014 setup, but quickly changed it, as the bike was packing at 14 clicks out (reb). i am now running a similar stack to that of the euro config.

 

i've tested with links, and no links. the bike is better without a link from my rider feedback. 

 

with a link the forks need to be pulled up quite far.

It likes a stinkbug type feel to handle and track well....which some riders dont like in just feel of a bike.  Once you let them go the other way, and the bike turns to shit - they realize it's the way to go

 

sounds like we've headed a similar direction in settings.

 

Something else to try for faster guys is actually a softer rear spring than usual - stiffens rear end to sag point - which helps load the front under breaking.

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I've also considered a single stage comp stack for the shock.

I have a few services this week which I will be making some changes. I had ordered a few shock spacers and was wanting to try them. One of my light, fast guys is getting exactly what you described in your earlier post.

I've not seen a 2015 yet. I'm curious about valving changes the factory made.

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Yes Guys, those shim dimensions are correct.

 

And yes of course spring binding causes the stock plastic spring seats to explode. And I`ve only seen this while using .54KG and heavier spring rates in previous years KYB forks.

 

Problem was always solved with billet seats.

 

 

I was trying to say a little more "room" (in between the coils) with the additional spring length should be a good thing for heavy rate springs in these new forks.

 

Sorry for any confusion:)

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So, I got everything set up last Thursday and did some testing on Saturday and Monday. 

 

Forks:

Stock BV

Midvalve- 1st 17x.11 shim replaced with 18x.11 shim, float set to .11

340cc oil

(Sand/black dirt track R10 C11)

Shock:

Removed 4 comp face shims

Replaced 36x.20 through 30x.20 comp shims with .25

Added 2x 40x.20 after 40x.30 in rebound stack (did not like this modification)

 

(Sand/black dirt track R9 C9 HS1.85)

 

Impressions,

Forks feel good after I went through my dumb phase of running the rebound clicker in too far, washing out the front wheel, and crashing repeatedly.

Shock felt good on comp, not so good on rebound stack

-With the 40x.20's after the 40x.30 the shock seemed too slow in HS reb dampening and too soft in LS reb dampening.  If I ran the clicker far enough out to get it to not pack in whoops it felt loose and floppy on braking chop and corners.  This morning I moved the 2x 40x.20's to the face shim stack.  Will test on Wednesday. 

 

Thanks for the help! I will try to keep this thread updated as I go along.  

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Got some testing in tonight, bike felt fantastic. Running rebound 16 clicks out on forks and 14 out on the shock now. Stock link installed with subframe lowered 25mm.

I can whip the bike without feeling like I'm going to die which is great. Turns much better too. Tracks through whoops. Super happy right now.

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with a link the forks need to be pulled up quite far.

It likes a stinkbug type feel to handle and track well....which some riders dont like in just feel of a bike.  Once you let them go the other way, and the bike turns to shit - they realize it's the way to go

 

sounds like we've headed a similar direction in settings.

 

Something else to try for faster guys is actually a softer rear spring than usual - stiffens rear end to sag point - which helps load the front under breaking.

harris would more sag and different offset triples will calm the rear and make it turn better?

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more sag makes it turn worse, and makes it more prone to headshake.

 

While I haven't tested any different offsets - I offer this up, yamaha in production testing tested every offset you can think of...in doing so their production settings are what it's sent with.
As the OP found out - the "stock" suspension settings were much closer than what he got the first go around.  To my knowledge travis preston played a big role in the 14 settings.  He's quite a good rider - and my impression of the bike is that it would work very well for a guy like him stock.

Shorter riders will struggle finding a happy medium of a low enough rear that will turn.

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So, got more testing in on a much faster, rough track this weekend. 

 

Found some limitations to my setup; I was get some major deathly headshake at entrances to high speed corners.  Almost got ejected going through some 8" deep braking chop on a hill when I was hitting the steering stops 4th gear pinned....

 

I think the problem is that the .47 fork springs I have installed aren't up to the task and the forks dive too easily.   Going to install the stock .49 springs and keep the 5.5 rear spring.   I'll give it a test run Wednesday and report back. 

Other than that, seems to work pretty darn good.

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