Posts
196
Joined
3/9/2022
Location
Ontario, CA
Edited Date/Time
4/16/2025 2:42pm
I am looking to purchase a used '24 KX450. I have found one that has been valved for a 200lb vet rider. I am about 240lbs with gear. My concern is that it is going to be too soft. I realize that at my weight, I would need stiffer springs and possibly valving as well, long term. But my understanding is that the stock valving would likely be okay for a 240lb vet c rider, with only springs being necessary.
What I am asking is, would the suspension on this bike valved for a 200lb rider be too soft? I do not want to spend money on suspension work without knowing if I will keep the bike. So trying to determine if I should pass on this one or whether it would be okay to start with.
Stock rear spring in the least to light for you and would think the 200lb setup would be closer for your weight than stock.
depending on your skill level, an under-suspended bike will get you into trouble on the track quickly.
Jump kickers alone will get you if the bike is under sprung or incorrectly valved for your weight, and you risk injury if the suspension blows through the stroke.
I own this bike and it was seriously way too soft for my 168 pounds less gear.
If the price on the bike is ok then you will probably need to spend $500 to $1200 getting the suspension set up for your weight, it is a good investment if you jump or ride tracks.
You will never have correct rebound control when changing springs that much and not fix the valving.
Thanks guys. My understanding was that the stock valving on the KX was actually a bit stiffer, better suited to heavier or faster riders. Trying to determine whether this valving has made the bike closer to what I would need or further away in comparison to how stock would perform for my weight. I would do suspension work if I were to keep the bike.
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Stock is generally aimed at 180-190 pounds so you would be closer to where you want to be than stock.
Thank you! Kind what I was suspecting. I know the rear shock spring stock is way too soft and I have no problem fixing that immediately. That is a given with any bike. I believe the stock fork springs are/were pretty close to where I would need? As mentioned above, if the valving is too soft, obviously that is going to affect overall handling and suspension function. But if I go with this one, I assume it should be good enough for a few hours of easy paced riding to give me a reasonable feel for the bike overall, with the expectation to spend the money to get the suspension dialed in thereafter.
I’m a 215lb winning Vet B motocross racer with a 2024 KX450. I added oil to both forks and replaced the fork spring in one leg with an optional stiffer OE fork spring. Out back, I went to a 5.9nm shock spring (which gave me the right amount of static sag), went out half a turn on high speed dampening, and in two or three clicks on rebound dampening (to compensate for the stiffer spring). With those changes, I don’t feel like I would gain much from a revalve, and I am very happy with my suspension.
If the one you are looking at was valved and sprung for a 200lb rider, you may need to go stiffer still, but I would doubt that the bike was revalved softer than stock for a customer that big.
Fork springs will be too soft as well. I would change springs front and rear which you could do at home and you should be pretty dialed for what your describing.
I'm 235 pounds. I went .52 on the fork springs 5.9 on the shock, stock valving. My 2024 KX 450 has been good with this set up. I'm a 57 year old intermediate Vet rider.
Very helpful. Thanks a lot guys. Appreciate it!
1st find out what springs are on it. It may be as easy as going to a heavier rear spring and a couple clicks stiffer on the rebound to compensate for the spring.
Also ask when was the last time the suspension fluids were changed. I would start with servicing the forks and shock and framing it to grease so you know what you have.
In stock trim, the forks are softer than the shock on this bike. The rear over powers the front in terms of balance.
57nm rear and 5.4 front with 370ml oil and you are good to go.
Awesome. Thanks guys!
Its impossible to know since every suspension tuner has different settings. But stock would work for you with spring changes. Stock valving is good for a C rider. I've taken them apart and know whats inside.
I have a rider who is a about 5lbs lighter than you. He's running a 5.8 on the rear and .54kg on the forks. You should be fine with a 5.8-6.0 kg rear spring and .54 fork springs.
Also the forks have plenty of reb dampening to handle heavier fork springs. Same with the rear.
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