Lowering The seat hight on my KTM


Bonehead

LIFETIME SPONSOR
Mar 15, 2001
406
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I did the forks and shock on my 520 and now I can't touch the ground . I saw a post way back when and now I can't find it.

I need to know how to cut the sub frame

It's a good thing it has the button or I would have to stop next to a stump to start it. Now I just stop next to a stump or rock to stop.

Short Guy On An Open Bike



00 520 EXC
00 380 EXC
 

Patman

Pantless Wonder
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Dec 26, 1999
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I believe Team KTM takes about 1cm from the bottom lateral which lowers the back of the seat close to 1 inch (scraching head):think . You might try cutting the foam down with an electric knife I'd bet you could get close to 2" if you were really aggressive with it.

Maybe if you started eating about a dozen Krispy Kream 's each morning and put on say 40 pounds you could sack out the suspension another inch or two. ;)
 

Bonehead

LIFETIME SPONSOR
Mar 15, 2001
406
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Thanks guys But I'm not sure if you cut the top or the bottom . If I cut the bottom, I have to move the mounting hole and nut ,I think I might need to cut the top?? not a problem for me to cut the top ,I'm a fabricator by trade.

BUY THE WAY Two springs stiffer in the front and one in the back this thing rides like an XR250 (Also did some valving)

00 520 exc
00 380 exc
 

rollingp

Member
Oct 31, 2001
393
0
about 1.5 inches above the bottom mounting hole you cut out 3-5mm of
tube than weld the tube back together.
Tig weld it.
This way all you are doing is rocking the subframe downward.
Watch your air box and carb flange if the air box rubs the shock that is not good and you don't want a bind on the flange to carb.
I have seen some serious holes worn through the air box between the flange and filter after too much was taken off the sub frame tube.
Some guys I know didn't like the lower seat after they cut the sub frame down.
They went back to running more sag front and rear and raising the fork tubes in the clamps.
I ride a 520 and I am 195 pounds 5.8 open A mx and I have last years pds spring on the shock which is revalved for more high speed comp and rebound.
The forks are stock valving with the air camber at 140mm and 1.5 turns out from 0 preload. 12 on comp and 14 on rebound .
For me the bike settles good and I can hold it up.
If the seat is too low towards the back or the sag is unbalanced from the front than as you probably know the bike will not turn as good.
I am on my 5th ktm since 98 and I get a new one every year.
We have a track here on our property that has everything on it
and we have done just about everything conceivable to the KTMs from the minis to the big bores. Suspension wise.
Mike weisner who was a factory KTM wrench for Kelly Smith has shed allot or light on the PDS system and made my shocks work better than the guys that
charged me an arm and a leg.
You really should be able to get your feet on the ground with set up before cutting your subframe.
 
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wcumbow

Member
Dec 19, 2001
4
0
Does removing 3-5mm from the subframe affect the fender, seat, or exhaust mounting?

Is there still plenty of clearance for the tire when the suspension is fully compressed?

Does anyone sell a seat with less foam to make the seat heigt lower?

Does anyone have experience removing some of the foam from the original seat?
 

rollingp

Member
Oct 31, 2001
393
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Remove the shock and let the bike set all the way down.
In stock form there is allot of room between the tire and fender when the suspension is completely compressed.
As far as the exhaust it will not bind and the fender will be in the same possition as always because it is attached to the subframe.
The seat will be a little harder to get on at first but it will contour to the change after a while.It is only at the tank it becomes snug.
It will go .
The main thing to worry about is the shock and airbox relation.
When the spring is compressed it will bow a certain amount and rub
on the air box boot to the carb. Also watch the top portion of the boot where it clamps to the carb. I have seen them pop off after a hard landing
because of the increased pull due to lowering the subframe. Each bike is a little different there so yours may not be effected.
 

PTCruiser

Member
Aug 25, 2000
73
0
I did the subframe lowering on my 400EXC AND did additional lowering with sag and moving up the fork tubes. This helped me a lot in the technical stuff where my lack of skill required a lot of dabbing. I did have to make a little bracket to get my silencer to mount back up becuase the holes were no longer aligned.
 

mb-quart 2

Member
Dec 20, 2001
4
0
shaving the saddle

i have alot of experience with lowering the seat height iam also horizontally challenged.iam only 5'2 and i ride a 125 .the best way to shave the seat down is to mark how much you would like to remove from the top,with a marker the use really coarse sand paper like 36 grit then smooth out with finer grades.works excellent and you won't have knife marks like using a electric knife you work with sand paper without taking to much off at a time. also you have to remeber while shaving the seat down you will be changing the seat to footpeg distance when sitting on the bike that has the sseat cut.
 

Jaybird

Apprentice Goon
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Mar 16, 2001
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You really should be able to get your feet on the ground with set up before cutting your subframe.
If a person has a 30 inch inseam, when the bike is set up spot-on..I garantee you he can't touch flat footed. Your sag set-up should never be altered just to accomidate your shortness. Cut the seat, lower the sub-frame and then if it's still too tall, mount a spacer on the shock.
I think Jeremy has recommended the latter first.

I think Skin Ind. sells a freeride flat saddle foam for the KTM's.
 

Jaybird

Apprentice Goon
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If you have a 30 inch inseam and the stock KTM seat and proper race sag, you cannot touch the ground. Try telling that to someone who doesn't know better. Tippy toe maybe :)

A shock spacer will restrict the rebound of the shock travel. Jeremy claims it will not effect the perfomrance of the shock.
 

rollingp

Member
Oct 31, 2001
393
0
Well I wont argue the point but you are wrong.
I have been racing these bikes for a long time and I know what works.
I can only say I sure would not limit my shock rebound
espeacially on a position and speed sensitive shock.
end of story.
 

Patman

Pantless Wonder
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Dec 26, 1999
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Seems to me there are several options for altering the bike for vertically challenged riders.

Claiming to "know what works" and not backing it up doesn't fly around here. Jeremy Wilkey is a professional, he will sit down and explain the hows and whys of his suggested mods in detail if you ask. I can assure you he will never expect ANYBODY to go with "I know what works" or "I've been doing this a long time..."

So, put up or shut up on the whole "I know because I know..." story line.

And is the end of that story.
 

rollingp

Member
Oct 31, 2001
393
0
My info comes directly from Kelly Smith x mech and from a source
at ktm USA not a back yard suspension valver.
Ride what you like I am done with this issue.

It is clear you are one of these guys that believes in the gimmicks sold by
so called suspension professionals.
( gold valves, bladders, etc etc.)
This stuff is all high priced junk that is no more effective than shim valving.
It takes about 25 years of racing and being involved in professional racing to
understand this. Set up your bike the way you want, spend $600.00 on your suspension I don't care but it is a waste off money and effort.
I would really not want to race a bike that has its suspension topped out as you are describing. If you really want accurate set up on a KTM you should get the facts from someone directly involved with the pro team.
Call Darren Borchading at factory connection.
The set up I run must be pretty accurate because I am in the top five in 25A and 30A consistently and took a top ten in the vet series on my 01 520sx . And my feet touch the ground. The end.
 

marcusgunby

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Jan 9, 2000
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RollingGP maybe the 520 you can touch the ground but on the 125sx with a 30"inseem you definatly carnt-open you mind to all possibilites.
Jaybird and others on this board are very knowledgable and would have tried setting the sag as a 1st step and have obviously found the seat still to high-i had a 01 125sx and was way off touching the ground-your remarks about jap bikes is also way off-you couldnt be more wrong-a jap bike like the Cr has a linkage so it stiffers up a fair bit more at the end of the stroke than the KTM-if you run a KTM at 105mm of sag you will limit its performance more than a Cr as you have not got the progression of the linkage to help on the bigger hits-i hope you will see the story isnt over till the fat KTM lady sings-your post have been informative and useful to members but its not worth throwing your dummy out of the pram when people disagree:mad:
 

rollingp

Member
Oct 31, 2001
393
0
John Dowd runs 105 mm
and you need to know that no two progressive springs test out the same so
the sag is more variable on a KTM than a jap bike or a bike with a straight wound.
The biggest problem with new to KTM riders is they always want to set the rider sag like a jap bike.
Free sag is more critacle and there is more room to play with rider sag
by seat of the pants feel. As long as your rider sag numbers arent extreamly off one way or the other( IE spring too soft or too stiff ) then there is the ability to give yourself the added drop to touch your feet.
Putting a spacer in the shock changes when the spring begins to get progressivly stiffer because the actual travel of the shock is shorter.
Now you have a spring that becomes longer in ralation to the shock and you are back to a three inch shaft and feel verses the new 4inch shaft .
Coil bind is sooner pre load is increased .
KTM , and Pro action, recommend setting the unladen sag
at 35-40mm and only suggest checking the rider sag as a reference to check whether the spring is too stiff or too soft for the rider.
The rider sag is not crucial. White Brothers recommends a straight rate on all KTMs even if they are not valved.
The valving and the position of the shock shaft play a bigger part in the
the performance of the pds system than the spring progression.
Yes the pds system has a flatter progression curve than a cr because it doesnt have a linkage but you are assuming the progressive spring makes up for that and to a very small degree it does. But the internal valving
is what really does the majority of the work.
Have you ever tried a straight wound spring on a pds system?
If you have say an 8.4 or an 8.9 you would understand what I am talking about.You guys have got to keep an open mind on this stuff. I am not trying to win an argument or put anyone down. We are all riders and racers but
I would like to say I was directly invoved with the 98 pds system when it first came out.
It was harsh and no-one early on had an idea of what to do with it.
They had a long needle and very restricted free bleed.
We were making our own needles and drilling bleed holes in the pistons.
All the new KTMs have a very short needle and this is what controls the last inch of shock travel for bottom out resistance.
The free bleed is greatly improved and the progressive valving of the shock is much better. If you get the fork and shock balanced even with a little more rider sag a short guy can ride the bike with less effort and being lower the bike will handle better. There is a point of going too far but again it is more seat of the pants feel espeacially on the shock.
Try it once you can always go back. Allot of riders were shocked to find that Langston runs his steering stops all the way out and you would think the bike would be hard to turn. I was doing this not 30 min after owning my first pds KTM in 98. This keeps the bike from knifing and pushing the front wheel.
The rider can lay the bike over more and once used to the set up he can get on the gas sooner and harder.
I was glad to see Langston riding for KTM because he had allot of experiance with the bikes before comming to the USA.
You will find a straight rate spring makes the ktm super plush yet still is resistant to bottoming. It settles more going into a turn and when you roll on the throttle the tire is pushed into the ground giving you major traction.
Clearing doubles the bike stays lower and is a little harder to get lift from launch. It is harder to turn because the rear end sqauts more.
Ajustments can be made in fork position , pre load etc and valving .
What I am trying to say here is you really cant say if the rider can touch his feet with a 30 inch inseam than the set up is way off because this simply isnt the case.
If it were than you wouldnt be able to do things like run a straight rate
a progressive etc. I will tell you most of these stock progressive springs
are the reason some of thes KTMs feel so harsh.
They dont test out at what they claim.
Out of three 02 520s with pds 7 advertised 7.6-9.5
mine was 7.15-10.9. another was 7.0-9.0 and one was 7.50-10.0.
When tested and different compression lenghts the numbers were way off.
My bike was riding in the middle of the stroke where the spring gets up to 9.5
and all the little bumps were bone jarring. Putting on last years pds 6 worked better.
We discovered the first three coils of the stiffer pds 7 was being used up
just sitting on the bike. The pds six ,a softer rated spring actually
was firmer on the initial stroke.Smaller bumps were absorbed better and the bike sat the same height.
We valved in more high speed comp and that was all we needed for
my weight.The straight 8.4 was truley 8.4 and worked even better than the pds 6 progressive on the high speed small stuff.
This was before we valved the shock. I think the progressive works better overall for most tracks espeacially sx type.My point is nothing is cut in stone with these bikes.
Remember the first pds came wth straight rate springs.
They relied on the long needle to resist bottoming.
You can do much more with the new shocks .
Cutting the subframe is fine but as I said before you have to make sure
other parts of the bike arent in risk of damage.
We have a guy out here that took 10mm off the lower strut
put more preload on the shock and balanced the bike front to rear.
It worked great but at the end of the day the sub frame was cracked and the air box boot had a large hole worn in it from the shock spring bowing against it. The tire was hitting the fender. Stock the tire never comes close.
Lets move on to something else.
All I can say is maybe try it first and dont put so much faith in these suspension guys. They are making a living at this.
They want everyone to think this is a hard task to do and there is
only one way etc. I wasted allot of money on the gimmicks early on
and thats one reason I and a bunch of my long time riding freinds switched from jap to KTM .Remember the Europeans invented this sport.
Every person I know from C rider to A rider instantly became a better
rider when they rode a KTM even out of the box stock.
There is allot of resistance from suspension companies, magazines
and jap manufacturers about these bike. They are a big threat
because they are so good. Other makers are on the japs heels TM,
Husky,cannondale,etc. BLA BLA BLA
Merry Cristmas.
 

marcusgunby

LIFETIME SPONSOR
Jan 9, 2000
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RollingGP thats the kind of answer that is appreciated here-its all about backing up answers with hard proof.If you dont mind can we go into a few points you raised.

The free sags importance i dont get-i know KTM says it should be this way but IMO isnt it better to have the rider sag correct then the fork angle is as expected.

When installing a shock spacer the spring is wound up the threads so it starts compressing the same as normal-you just have a bit less travel which does mean the progression is advanced but not much progression exists at this part of the travel.

Coil bind as far as i know is when the whole spring is coil bound-the top three coils are designed to close up 1st thats why you take measurements at 20mm

I adgree the spring doesnt make the systam as progressive as a jap bike and the 2nd piston has to take up the job but im not sure which bike has the most total damping on bottoming?

I used a 7.5 straight rate spring on my 125 sx and it steered better and was plusher-i liked the 7.5 or the pds1 -straight rate was best.

When you say involved in the 98 PDS -was you a tester or a engineer-not doubting you just interested.

I have wondered about having a bleed hole in the piston-it would be one answer to the problem-have you modified the comp adjusters at all?

I adgree 100% on the springs varying-this is not good.

The bit about a rider going faster on a stock KTM-you cant have ridden a 125sx-its a bone jarring beast,i rode a 520 set up for a 230lb rider(i weigh 170lb)and it was way plusher than the 125sx std or modified.
The 125/200 acts differently to the bigger bikes as the unladed weight is less and the shock just refuses to move into the stroke then all of a sudden it blows through and bottoms out.I know valving makes it better but its very hard to get a decent compromise.I spent weeks valving a 125sx and at best it was worse than a std CR125-the Cr i could almost mix shims up stick them in and i would still be better.
I had settings from the champ KTM team and GP team techs and i still wasnt very good-no championship bikes in euro land have ever raced with the std forks/shocks-thay all run SXS or works and some have to buy the SXS so its not a case of running what it because its free.


I adgree alot of suspension companies shy away from the PDS but who can blame them the costs of servicing is unreal for all the Gizmos, and the cost is hard to recoop because the market is small.

On suspension companies -Jer isnt the type to try to flog people stuff becuase he knows best(im not saying you directed your comments at him BTW)-his forum is designed to enable riders to make informed decisions based on knowledge gained-your input there would be great BTW.

Ive enjoyed this thread and have a happy christmas
 
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Jaybird

Apprentice Goon
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The math just isn't there, Dr. rollingp. Even though you have your bike squatted out you still lack numbers to have a firm foot down.

I'm curious...I'm 5'7" and weigh 180 lbs. and I'm FAT! Now you have the same inseam as me and you are 195 lbs? Let me suggest a very economical modification that will boost your complete package, HP, suspension, the works...wait...maybe I better not.:debil:
 

Patman

Pantless Wonder
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Now that's a little more like it.:) As Marcus pointed out facts and figures to digest, review and even question are what it's all about. Since this seems to be getting a bit more in depth it seems a good time to relocate and see what some other points of view may have to say.
 

Bonehead

LIFETIME SPONSOR
Mar 15, 2001
406
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Dam , all I wanted to know was how to cut the subframe.

About the high priced junk ,I will run my high priced junk over yours any day.
It's how you put it all together for your style of riding .if you can find a guy that will build your suspension for you specifically, you can get what your looking for and you can bet your A-- that all the pros in all forms of motorcycle racing have something other than the way it came in the crate.

The problem is most shops get a setup for there top pro in the area and they think it will work for everybody.

I think I should know something about this because I won the Funky Chicken National Hair Scramble this year in the OPEN A class by over 6 1/2 min
and I was a support rider for team Honda 1982 ,83 and 84 and the shocks and forks I had weren't the ones that you got.


P.S. this has turned into a great post and yes you should move it so we can hammer out all the suspension stuff
 

rollingp

Member
Oct 31, 2001
393
0
02 forks use 01 sxs valving and internals.
02 ktm shocks are almost as easy to service as japs.
the air can be bled without the use of a evac pump.you still need a charging stand for the nitrogen.
Yes I was involved with the factory testing of the 98 pds suspension .
Usually if a straight rate feels plusher though the entire stroke it is a sign the
spring rate should be changed to the next lowest number .
It can indicate the spring is riding in the firm part too early.
This is why trying different springs of the same rate is important.
One spring may be at 1025 lbs at 3 inches of compression and the other may be 1000 and both springs are advertised at the same rate . Some will say that is not enough of a difference to tell but it is.
It is noticeable once put on the bike especially if both springs are starting out about the same numbers on the first three coils which is the softest part of the spring.
This is where I am referring to coil bind not the entire spring.
Whether you believe it or not Kelly was running a bone sock production bike
while racing the 4 stroke nat.
When he came up short at Red bud and ripped the motor out of the frame
made the steering stem look like an s and crushed the front wheel
he was on a bone stock production bike . Even the suspension was stock except for the shim valving.
He finished the series on a used exc that was at a dealer.
They revalved it for mx and geared it.
KTM didn't even want to give them titanium axles, swingarm pivot.
or steering stem until this happened.
Dowds bike for 01 was the platform for the 02 production bike.
His motor was bone stock and de tuned for less hit off the bottom That bike is as stock as it gets except for the ti pivots and some fasteners. Also the pipe.
Triple clamps and dampener. KTM has a sell what we race attitude.
Even Dowds shock is completely stock except for the shim valving
and he runs a PDS spring 8.0-10.3.and has tried the bladder.
Spacing a pds shock isn't a good idea because you are losing some of the shock efeciancey. Especially on small acceleration bumps.
The first piston in this shock does 95 % of the work very much like a normal link shock the second piston is along for the ride until about the last
1 inch of stroke. This is where the needle mounted inside the shock body at the very top enters the shaft and restricts the oil and diverts it through the
second piston and its shim stack. Loosing any initial travel on the first piston
results in loss of some efficiency and why would you want that?
You wouldn't skimp on anything else on your bike
Would you run a champion spark plug in your bike to save $5.00?
Ktm lengthened the 02 shock shaft to give you what you are talking about giving up to some degree by putting a spacer in there.
I have ridden all the 02 KTM bikes this year and yes the 2 strokes
are not as plush as the 4 strokes but this is more to do because of the engine
differences. We didn't have any trouble getting the two strokes to
be plush . Yes we revalved the shock for more high speed comp.
Got way away from the stock clicker settings and
backed off the pre load on the forks went to the lightest oil and ran from
120 to 160 on fork oil levels .
I am not saying valving the forks wouldn't make them better but
we did just the shock and made a few spring changes.
So far everyone is happy with that.
I am not the doctor here but I am sticking to my guns about
the relative ease in which to get these KTMs to work.
I still feel most of these bikes have much better suspension action out of the box than any jap bike I have had over the last 20 years.
If you really want a set of forks that work great try a set of 98-99, 50mm conventionals with a summers racing fork brace.
They have a large bottom out cone and hold so much more oil than an
inverted. The action is plush and there are some benefits to the lower center of gravity. The only fall back is they flex to a degree but for the average guy
it is not a concern especially with a fork brace.
Most cant get past the hype about the flex part.
We ride mostly high speed open tracks and these forks are almost like cheating. The 4 stroke is awesome with these. Yes to a degree the inverted forks can be valved to be much better but it is almost impossible to duplicate the bottom out action of the 50mm white power forks. Just by the shear size of the bottom out cones and the hydraulic lock they provide. The inverted forks don't have the space to duplicate this.
Remove the seals and tighten the springs and keep the dust wipers
clean and they wont leak.


to cut the subframe :
make a mark about 1.5 inches above the lower subframe mounting bolt.
Remove the seat, silencer, number plates, fender , shock flap and the sub frame.
Remove the air box .
Cut 5mm out of the subframe where you made the marks on each side.
clamp the subframe lightly in a vise and file a chamfer in the cut ends.
Also do this with the pieces that are cut off and must be tig welded back to the subframe.
Take a straight edge and using two welders clamps return the cut off pieces
to the sub frame.
Use the straight edge to check for plumb at all sides while clamping.
Use arcaloy or another welding brand of cleaner to clean the areas to be joined.
Pre heat the two parts with a propane torch but just to warm it.
Tack the pieces together making sure not to let it pull from the heat
( they must stay as straight as possible.) Weld it together and leave the bead.
Grinding it off will weaken it. Use some polish to brighten it back up.
Put everything back together. You will need to loosen the bolt that holds the two headers together and the rear header mount bolt.
The extra play will let you get the silencer back on .
The bolt holes will be off just enough to not go if you dont loosen the header bolts.
The 5mm will lower the seat about 15 mm. This doesnt sound like much but when you sit on the bike it feels like allot compared to stock.
It is noticable looking at it from the side.
The bikes we have done this to reacted worse to turning on tight tracks until we slid the forks up and got a balance. 10mm We ran the shock at maximum allowable preload.
Going to the 18mm offset worked even better.
The ride is much flatter. We cut one bike down 10 mm
and had to make a silencer bracket.
The tire destroyed the fender and the air boot developed a hole.
But this is what the owner wanted to try.
5-7mm is a good range.

PS> I want to make it clear I am not talking about what Honda, Yam,
or Kaw uses on there pro teams. Everyone knows they run as much high end works components they can get away with. They sell a much inferior
product to the public. I am talking mainly about what KTM does.
Dowds motor was never taken apart until the race at Red Bud when it was
shipped back to ktm to be autopsied. It had all that time on it. This is a fact.
Also no disrespect but we are mx racers not woods and most of this info
from my post is for mx racing. A stock sx would be a ***** in the woods.
You say allot of suspension companies dont want to work on the KTM shocks.
Doesnt this tell you that they dont understand how it works, They are very easy to service and because of the steel body dont reguire as freqeunt
a maint. schedule. The system is a good one and for bottom out control works better than most link bikes. It is simple simple simple. The 02 is the easiest to work on .The shaft nut screws off and doesnt reguire grinding.
You need two screw drivers, an open end wrench to fit the shaft nut,
a charging stand ( make one ) some nitrogen ,oil and a caliper.
It takes no more than 20-30min to revalve a KTM shock and
about 3 min to put the spring on ( compresser) Unless you are changing needles ( diameter and length or drilling bleed holes(98-99) they dont require
much effort. Anything before 01 you had to evac the oil as you filled the shock using a closed pump unit otherwise the air would get trapped especially
on th 98 because the oil had no free bleed and had to run all the way through the shaft to the bottom and back to the internal body.I have seen
shocks that were done by reputable suspension companies come back with trapped air and over or under charged nitrogen levels.The most difficult task is making darn sure the air is out and the correct nitrogen pressure is used.
The piston must me located in the correct height when charging after filling with oil.Remember the nitrogen piston only moves about 5 to 10 mm back and forth.
Also I am not saying you should be able to flat foot the ground but why would that be so important?
I am saying you should be able to touch the ground ( balls of your feet )
and 105 mm of rider sag is not a squatted bike and results is no adverse effects at least the bike has all its shaft travel to use. Lets Ride!
 
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