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Discussion Starter #1
I'm wondering if anybody's adjusted the rear spring preload in their Ninja 400.

From the manual, 1 is softest and 5 is hardest and 2 is the factory setting.

I'm a fairly light rider (155 lbs), mostly commuting (at least until I'm through the break-in) and the roads are of average-ish quality. So 2 *sounds* okay, but I was thinking of tweaking it and I was wondering what other people's experiences have been. Also, is there some position I should aim for while my weight's on the bike?
 

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I havent played with mine because the standard setting of position 2 provides about 10mm of bike sag (I measured it) and this is an ideal figure for suspension set up.
Are you wanting to lower your seat height a bit? If you are then go to position 1.
Or are you wanting to make the ride firmer or softer?

It's the old story, just have a play with it, You've got nothing to lose.
I'm assuming you got the 'C' spanner adjusting tool as part of your tool kit?
 

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Spring preload adjusts ride height (not spring stiffness). When you set preload according to your weight and preferences your suspension will operate within its optimal range of motion.

Also, is there some position I should aim for while my weight's on the bike?
Have a friend help you measure and adjust your "rider sag". Optimal sag is typically 25-33% of the rear wheel travel distance (5.1 inches / 130 mm for the Ninja 400).

Search for:
motorcycle rider sag

Here's a video:
 

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I adjusted mine up two notches firmer, since I am a heavier rider (265 lbs). It is one from the firmest setting for me, and it was a definite improvement.

My suggestion is to move it one notch, and ride it around. See if you like the change in handling/ride quality. If so, you can try another adjustment. And, of course, you can't go wrong with a good baseline setting, as is outlined in the above posts.

The really important thing is how the settings fit your roads and riding preferences....imo. :)
 

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I'm wondering if anybody's adjusted the rear spring preload in their Ninja 400.

From the manual, 1 is softest and 5 is hardest and 2 is the factory setting.

I'm a fairly light rider (155 lbs), mostly commuting (at least until I'm through the break-in) and the roads are of average-ish quality. So 2 *sounds* okay, but I was thinking of tweaking it and I was wondering what other people's experiences have been. Also, is there some position I should aim for while my weight's on the bike?
FWIW: Me at 170 to 180 depending on attire.

# 4 got me 28 mm sag....# 2 was about 33 mm sag.

The front end was 33 mm sag, so good to go , since I set

my adjustable bikes at 30 to 35 mm front sag.

Ran it on Palomar Mountain and it was spot on.
 

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This only lowers ride height. Not stationary height correct? I could use a lower seat height when trying to get my short little legs over the bike but it sounds like this is only gonna help for when I am already on it. Is that right?
 

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This only lowers ride height. Not stationary height correct? I could use a lower seat height when trying to get my short little legs over the bike but it sounds like this is only gonna help for when I am already on it. Is that right?
It changes both. Stationary height is called static sag and ride height is called rider sag. They are both measured from a bench mark position that never changes (regardless of spring preload setting) and that is with the rear of the bike fully unloaded. ie The weight of the bike is supported on the footpegs so that the suspension is fully unladen and the rear wheel is off the ground.
 

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It changes both. Stationary height is called static sag and ride height is called rider sag. The are both taken from a bench mark that never changes (regardless of spring preload setting) and that is with the rear of the bike fully unloaded. ie The weight of the bike is supported on the footpegs so that the suspension is fully unladen and the rear wheel is off the ground.
Oh cool. So, since I'm a new rider and don't know what changing the suspension will do, as a 170 lb rider, how will lowering the suspension effect the performance of the bike for me? Is it advisable to lower it at my weight? Essentially I just want a little lower seat height, it's comfortable enough while I'm mobile. Any input or suggestions are welcome. Thank you!!
 

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Oh cool. So, since I'm a new rider and don't know what changing the suspension will do, as a 170 lb rider, how will lowering the suspension effect the performance of the bike for me? Is it advisable to lower it at my weight? Essentially I just want a little lower seat height, it's comfortable enough while I'm mobile. Any input or suggestions are welcome. Thank you!!
Position two is standard factory setting so going to position one will lower the rear of the bike slightly but your not going to notice a massive difference when throwing your leg over. A few mm's, but it all helps.
You may also notice a slightly softer ride when you hit bumps and things esp around town but ultimately at high speed you need to swap out the whole spring for one of a softer or harder spring rate if you really want to make big changes to your suspension set up.

You are only 40lbs heavier than myself and I think the spring rate is Ok for my weight. Kawasaki has stiffened the spring rate from the previous N300 as this was one of the criticisms riders had of that bike. The weak point of the OEM rear shock is not so much the spring but the internal valving that controls the compression and rebound action of the shock.
 

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I'm 265lbs after I brought the bike home the first day I hit it up to 4. Road that for about 200 miles then hit it to 6. That's where I've had it since and it feels fine/good to me. But don't really have anything else to compare it too.
 

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I'm a tall rider, still waiting for my bike to be delivered this weekend. when sitting on the bike a the dealership I can stand flat foot just above the seat at 6" 4'. I'm thinking I should raise the ride height but I'm in the 90kg range. So raising the ride height won't affect the sag?
 

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I'm a tall rider, still waiting for my bike to be delivered this weekend. when sitting on the bike a the dealership I can stand flat foot just above the seat at 6" 4'. I'm thinking I should raise the ride height but I'm in the 90kg range. So raising the ride height won't affect the sag?
It will reduce your sag slightly as you are putting some tension or pre load on the spring when you turn the adjuster, but it won't be dramatic.
To really change your sag measurement you have to swap the spring out for one of a different spring rate.
 

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Position two is standard factory setting so going to position one will lower the rear of the bike slightly but your not going to notice a massive difference when throwing your leg over. A few mm's, but it all helps.
You may also notice a slightly softer ride when you hit bumps and things esp around town but ultimately at high speed you need to swap out the whole spring for one of a softer or harder spring rate if you really want to make big changes to your suspension set up.

You are only 40lbs heavier than myself and I think the spring rate is Ok for my weight. Kawasaki has stiffened the spring rate from the previous N300 as this was one of the criticisms riders had of that bike. The weak point of the OEM rear shock is not so much the spring but the internal valving that controls the compression and rebound action of the shock.
This is good info for me as my weight fluctuates somewhere between 130 and 145. I thought that maybe the ride was too stiff because of how much I get bounced around. But I think it's more because the roads I'm riding on are so awful lol.
 

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This is good info for me as my weight fluctuates somewhere between 130 and 145. I thought that maybe the ride was too stiff because of how much I get bounced around. But I think it's more because the roads I'm riding on are so awful lol.
No your right, for someone of our weight it is too stiff on less than perfect roads. I'm actually really surprised to see I typed that. Men are allowed to change their minds too right? :biggrin:
I've since gone for an aftermarket shock that I was able to order with a softer spring. Much better. Before when I sat on the bike I was only compressing the rear end an inch from the fully unloaded position (rear wheel off the ground) and that's about what you expect of a race bike with stiff suspension.
 

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No your right, for someone of our weight it is too stiff on less than perfect roads. I'm actually really surprised to see I typed that. Men are allowed to change their minds too right? :biggrin:
I've since gone for an aftermarket shock that I was able to order with a softer spring. Much better. Before when I sat on the bike I was only compressing the rear end an inch from the fully unloaded position (rear wheel off the ground) and that's about what you expect of a race bike with stiff suspension.
Ahhhh alright, appreciate the response. I'll give it a shot turning it down a notch and see how that works. Then maybe I'll change it back if I decide to hit the track lol. A new rear shock is something I'm interested in since I have heard it has some pretty immediate benefits. Looking at the Ohlins STX36 right now. What did you swap the stock one with? And have you changed the front suspension too?
 

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Ahhhh alright, appreciate the response. I'll give it a shot turning it down a notch and see how that works. Then maybe I'll change it back if I decide to hit the track lol. A new rear shock is something I'm interested in since I have heard it has some pretty immediate benefits. Looking at the Ohlins STX36 right now. What did you swap the stock one with? And have you changed the front suspension too?
Nah the front feels about right, it was just the back I had beef with. Any aftermarket shock will be an improvement as you will be able to chose your spring rate and have the facilty to fine tune your damping as well. Ohlins is quality stuff, could'nt go wrong there, but Penske, Nitron and K-tech (which I went with) are good brands also. Pity they are all so dam expensive!
 
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