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Tuning your suspension - Where to start?


Bryan II

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9 hours ago, Oregon Comrade said:

I really like the laser idea...but how did you mark the wall if you are sitting on your bike?

Handlebar was close to wall. balanc it just long enough to turn around and mark the decrease. Better if you have a helper. Best susp/handling tutorial i've found on the web is over on slavens' website.   

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  • 7 months later...

2007 yz250f rider weight 160 fully outfitted
Novice rider, set for 100mm sag but think i will increase to 110 to lower seat height from 37" to closer to 36"
15 year old 5 foot 7" figured better control would benefit more than ideal setup.
And setup on rebound and dampening vs stock.

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  • 3 months later...

I just went through this. I have 2019 kx450 spring forks with Honda billet lugs for my 07 CR250. Knowing they would be to heavy/stiff for me I wanted to ride them before changing springs/valving. I decided to start with a low amount of oil after putting them back together after the lug swap. Even though most reviews said the 2019 kx forks felt soft I thought they would be harsh going on a lighter bike with my 155lb ass on it. They actually felt better on the first ride than my older KIT forks did. They were more plush on the smaller bumps/normal riding terrain but still had a slight “jackhammer” feel. Even though I’m my head I was convinced the valving and springs were to heavy from the start, I decided to add more oil to the forks. I ended adding another 30cc and it was a win! The forks feel plush and smooth and flat out great. I don’t see any need to change the valving or springs because they feel so great (but I will anyway).

So.... adding more oil is supposed to increase bottoming control and stiffen the forks. I could be way off here but.... I suppose adding fluid could also help the forks stay in the upper stroke where the forks is more plush. Play around some and find the sweet spot. I started with a low oil volume so even adding 30cc I’m still in a lower range but it worked for me. I’m sure there’s a point that the forks will become harsh with a high oil volume. It’s easy to experiment with although and could pay off.

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I just went through this. I have 2019 kx450 spring forks with Honda billet lugs for my 07 CR250. Knowing they would be to heavy/stiff for me I wanted to ride them before changing springs/valving. I decided to start with a low amount of oil after putting them back together after the lug swap. Even though most reviews said the 2019 kx forks felt soft I thought they would be harsh going on a lighter bike with my 155lb ass on it. They actually felt better on the first ride than my older KIT forks did. They were more plush on the smaller bumps/normal riding terrain but still had a slight “jackhammer” feel. Even though I’m my head I was convinced the valving and springs were to heavy from the start, I decided to add more oil to the forks. I ended adding another 30cc and it was a win! The forks feel plush and smooth and flat out great. I don’t see any need to change the valving or springs because they feel so great (but I will anyway).

So.... adding more oil is supposed to increase bottoming control and stiffen the forks. I could be way off here but.... I suppose adding fluid could also help the forks stay in the upper stroke where the forks is more plush. Play around some and find the sweet spot. I started with a low oil volume so even adding 30cc I’m still in a lower range but it worked for me. I’m sure there’s a point that the forks will become harsh with a high oil volume. It’s easy to experiment with although and could pay off.

I have found sometimes forks get plusher with more oil
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I just went through this. I have 2019 kx450 spring forks with Honda billet lugs for my 07 CR250. Knowing they would be to heavy/stiff for me I wanted to ride them before changing springs/valving. I decided to start with a low amount of oil after putting them back together after the lug swap. Even though most reviews said the 2019 kx forks felt soft I thought they would be harsh going on a lighter bike with my 155lb ass on it. They actually felt better on the first ride than my older KIT forks did. They were more plush on the smaller bumps/normal riding terrain but still had a slight “jackhammer” feel. Even though I’m my head I was convinced the valving and springs were to heavy from the start, I decided to add more oil to the forks. I ended adding another 30cc and it was a win! The forks feel plush and smooth and flat out great. I don’t see any need to change the valving or springs because they feel so great (but I will anyway).

So.... adding more oil is supposed to increase bottoming control and stiffen the forks. I could be way off here but.... I suppose adding fluid could also help the forks stay in the upper stroke where the forks is more plush. Play around some and find the sweet spot. I started with a low oil volume so even adding 30cc I’m still in a lower range but it worked for me. I’m sure there’s a point that the forks will become harsh with a high oil volume. It’s easy to experiment with although and could pay off.


Great info, thanks a lot. I actually am in a similar situation… I have a 2005 RM 250 that I purchased and the previous owner had the suspension done by factory connection, he was a much larger rider (190 pounds)as to where I’m only 160 pounds myself.
The suspension is not awful but I do feel like it could be a bit softer. I have the motion pro tool on the way and will begin searching for that sweet spot.
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  • 1 month later...

I think what is confusing the guy is the table is showing less oil on the hard setting and more oil on the soft setting when compared to the standard settings. The reason for this is the thickness of the coils themselves so the oil level is adjusted to compensate for the oil displacement of the spring in order to keep the oil level at the same height.

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  • 5 months later...

6.10 kg/mm is the recommended spring for just your body weight, but the closest spring is 6.0kg/mm. However, considering the extra cargo weight, I'd go with the next next heavier spring of 6.3 kg/mm.

https://thumpertalk.com/shop/Race-Tech-Shock-Spring-DR-Z400-ALL-p2006835316.html

We don't have the 6.3 listed for some reason, but we sell it. It's p/n SRSP 672763. If you order, order the 6.0 and in your order notes, put in p/n SRSP 672763. Same money, so we'll just edit your order and send you an updated invoice. We ship to Romania via USPS Priority Mail International. Pretty quick and no brokerage charges like FedEx or UPS. There's a standard service that's about 7 days (excluding customers) and an express option as well (more money). Shipping calculations can be see before checking out by adding to your cart.

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  • 1 month later...
On 1/14/2020 at 7:12 PM, Pisrael said:

Look for help on setting up my forks on 2020 ktm 350 xcf. What air should I run and clicker settings I weigh 220 ?

1st stop is a new rear spring. You're too heavy for its rate, so you'll not be able to get the sag in spec. That's where's I'd start first if you've not already. Once you get your sag dialed in, then you can work on the rest of the settings. The rear is pretty easy, but the AER48 takes more time to get dialed in. And, know that the fork takes at least 10 hours to break in. 

Tons on AER on TT: https://www.google.com/search?source=hp&ei=LuMhXpqjAs7t5gL-74CwBw&q=site%3Athumpertalk.com+"aer+fork"&oq=site%3Athumpertalk.com+"aer+fork"&gs_l=psy-ab.12...271.23751..25270...22.0..2.410.5752.32j12j2j1j2....2..0....1..gws-wiz.......0i199i291j0j0i131j0i199i175j46i322j46i322i131j0i10j0i22i30j0i22i10i30j33i160.kFvidqOwVJE&ved=0ahUKEwia8vSliYvnAhXOtlkKHf43AHYQ4dUDCAw

In google type: thumpertalk.com 

and after that, type your keywords. If there is more than one work, use quotes: 

thumpertalk.com "aer tuning"

thumpertalkcom "aer setup"

 

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Step #1; Set your sag (or get it close) and write down results (static off, dynamic off, etc)

Step #2; Unbolt suspension

Step #3; send it to a suspension guy along with your height, weight, riding style and Step #1 info

Step #4; pay

Step #5; bolt it back on and set it up based on your suspension guys' recommendations

 

I've found that is the easiest and quickest way to get suspension dialed in.  Many of these newer forks are notorious for having adjusters that don't do much or have a very narrow range of adjustment, it can be frustrating until you get that sorted out by a good suspension tuner.

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1 hour ago, Oregon Comrade said:

Step #1; Set your sag (or get it close) and write down results (static off, dynamic off, etc)

Step #2; Unbolt suspension

Step #3; send it to a suspension guy along with your height, weight, riding style and Step #1 info

Step #4; pay

Step #5; bolt it back on and set it up based on your suspension guys' recommendations

 

I've found that is the easiest and quickest way to get suspension dialed in.  Many of these newer forks are notorious for having adjusters that don't do much or have a very narrow range of adjustment, it can be frustrating until you get that sorted out by a good suspension tuner.

I've not sent mine away and don't plan too. I guess it depends upon where you are riding and your skill. I'm faster C rider, riding the sandy woods of central FL. For me, the stock set-up  adjusted is just fine. But to be fair, couldn't find a rock here you wanted one. Set up for these conditions is less demanding.

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