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Discussion Starter · #1 · (Edited)
So a basic budget setup that does wonders!
Check that the Stock fork And shock are sprung to your weight.
if don’t meet the 30-40mm Riders sag requirement Front and rear definitely start off with a spring change and is usually $300 for both fork and shock.
Yes you can re spring the stock throw away shock.
Non adjustable damper rod forks stock they have 10w fork oil, Minimum for track is 15w fork oil standard oil height, this gives you absolutely premium rebound damperning for street and a great start for track.
Fork oil changes for non adjustable are when either the fork bounces Twice on the bounce check or minimum 5k Miles.
I demand a little more feedback so I change every 5000km fork oil is cheap so it’s great performance for the money.

For the stock OEM throw away shocks which are not rebuild able, they have no rebound damper left by 11k miles and destroys tyres so a cheap alternative is to swap it out for another fairly new shock every 10000km or at the latest 10k miles.
This should keep you fairly happy 😃 and consistent.

The very first thing I would do if have the extra cash is to get an aftermarket shock YSS around $550 that is service able which also has a ride height adjuster. This then makes geometry correction for a new tyre brand/model a whole lot easier!

Only when I bottom out the forks On the budget setup I have just explained, will then obtain fork preload caps and emulators kit Which is around $450.

So as is with my setup OEM Dunlop Tyres and my stage 1 upgraded budget suspension will keep me happy for ages.
Until I want to change or upgrade to a different tyre on the Budget track setup, then will change to an upgraded shock to correct geometry and then if I get faster I’ll upgrade the front...
Other than that The Ninja 400 has a fairly decent stock suspension setup if you know what your doing....
13021
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.... if don’t meet the 30-40mm Riders sag requirement Front and rear definitely start off with a spring change and is usually $300 for both fork and shock.

...Yes you can re spring the stock throw away shock.

...Only when I bottom out the forks On the budget setup I have just explained, will then obtain fork preload caps and emulators kit

...Other than that The Ninja 400 has a fairly decent stock suspension setup if you know what your doing....
I'm not trying to pick holes here, I can see you are enthusiastic about the subject of setting a bike up for the track, but I dont agree with all of your info:

Firstly, 30- 40mm rider sag is good for the front but not the rear. You want 25-30mm on the rear for track riding, no more.

You can not re-spring the stock 'throw away' shock as it's not rebuild-able.

Waiting until you bottom out your forks is not an ideal approach to deciding when you start your front end upgrades. Have you ever hit the bottom of your stroke when hard on the brakes coming into a corner? If it happens as your starting to tip the bike in it makes your front end tuck under. Happened to me.

"The Ninja 400 has a fairly decent stock suspension setup if you know what your doing...." Only as a street bike, not as a track bike. It's basic non adjustable stuff built to a price point to meet the bikes total retail price. That's why a lot of us have changed our rear shocks to aftermarket brands.
I'm not even going to comment on the "if you know what your doing" bit lol 😄
 

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Discussion Starter · #3 · (Edited)
I'm not trying to pick holes here, I can see you are enthusiastic about the subject of setting a bike up for the track, but I dont agree with all of your info:

Firstly, 30- 40mm rider sag is good for the front but not the rear. You want 25-30mm on the rear for track riding, no more.

You can not re-spring the stock 'throw away' shock as it's not rebuild-able.

Waiting until you bottom out your forks is not an ideal approach to deciding when you start your front end upgrades. Have you ever hit the bottom of your stroke when hard on the brakes coming into a corner? If it happens as your starting to tip the bike in it makes your front end tuck under. Happened to me.

"The Ninja 400 has a fairly decent stock suspension setup if you know what your doing...." Only as a street bike, not as a track bike. It's basic non adjustable stuff built to a price point to meet the bikes total retail price. That's why a lot of us have changed our rear shocks to aftermarket brands.
I'm not even going to comment on the "if you know what your doing" bit lol 😄
Well mate let me try and clarify.
like it or not I run a recommendation of oil viscosity for track in those non adjustable forks. Also I am in school for suspension atm and yes you can re spring throw away shocks for your information Mate a re spring is not a rebuild.
im still 10mm off bottom out and having no handling issues, the moment I get under 5mm to bottom out I will add fork preload caps.
SO....
DMT recommendation is 30-40mm front and rear as a starting point. A flat bike is generally a good starting point....35mm front and rear.
yes some do like a starting point at 25mm rear, that is for people who can already run a track pace mate.
not everyone can run a track pace.
if you run 25mm of sag or want it good for you but can you use the stroke?.
if barley use 40% of the stroke front or rear your gonna have massive handling issues no difference to smashing flat because spring being to soft due to pace.
man you can start wherever you want in preload as long as it is within the 30-40mm
I would only recommend using 25mm riders sag rear if can run a track pace.
track or street only when bottom out You then add preload for the pace you developed.

I will post up My Certificate in Suspension Diagnostics and setup in the near future as that is my next line of work.
 

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So a basic budget setup that does wonders!
Check that the Stock fork And shock are sprung to your weight.
if don’t meet the 30-40mm Riders sag requirement Front and rear definitely start off with a spring change and is usually $300 for both fork and shock.
Yes you can re spring the stock throw away shock.
Non adjustable damper rod forks stock they have 10w fork oil, Minimum for track is 15w fork oil standard oil height, this gives you absolutely premium rebound damperning for street and a great start for track.
Fork oil changes for non adjustable are when either the fork bounces Twice on the bounce check or minimum 5k Miles.
I demand a little more feedback so I change every 5000km fork oil is cheap so it’s great performance for the money.

For the stock OEM throw away shocks which are not rebuild able, they have no rebound damper left by 11k miles and destroys tyres so a cheap alternative is to swap it out for another fairly new shock every 10000km or at the latest 10k miles.
This should keep you fairly happy 😃 and consistent.

The very first thing I would do if have the extra cash is to get an aftermarket shock YSS around $550 that is service able which also has a ride height adjuster. This then makes geometry correction for a new tyre brand/model a whole lot easier!

Only when I bottom out the forks On the budget setup I have just explained, will then obtain fork preload caps and emulators kit Which is around $450.

So as is with my setup OEM Dunlop Tyres and my stage 1 upgraded budget suspension will keep me happy for ages.
Until I want to change or upgrade to a different tyre on the Budget track setup, then will change to an upgraded shock to correct geometry and then if I get faster I’ll upgrade the front...
Other than that The Ninja 400 has a fairly decent stock suspension setup if you know what your doing....
View attachment 13021 View attachment 13022
i need the info on the spring used - length/weight for the rear shock re-build
 

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i need the info on the spring used - length/weight for the rear shock re-build
He's been banned, and for good reason.
Some one like racetech should be able to help you. I think your money would be better put towards an adjustable shock out of a GSXR or such like rather than spending it on a new spring for the stock shock which is very 'budget' in its performance and degree of adjustment.
 

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i need the info on the spring used - length/weight for the rear shock re-build
He's been banned, and for good reason.
Some one like racetech should be able to help you. I think your money would be better put towards an adjustable shock out of a GSXR or such like rather than spending it on a new spring for the stock shock which is very 'budget' in its performance and degree of adjustment.
I totally agree as well, the 2011 - on GSX-R 600 or 750 shock is your best bet, and a replacement spring with a different KG from Racetech or someone like that. If you search around there was 1 or 2 that actually did this. I think we also found out that a spring off another shock had the right KG and would fit the GSX-R shock on the cheap.

I also would not trust all his info, some of it was accurate and correct on the premise and basis, but after that, it got confusing and inaccurate or even in some cases counter productive. So take what you find post wise, from him, with a grain of salt, especially if it deviates from everything everyone else is saying and physics dictates.
 

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i need the info on the spring used - length/weight for the rear shock re-build
The gsxr shock swap is going to be better than just going with a spring swap and probably will cost you about the same. I paid $80 for a 2019 GSXR 600 shock off ebay and it's $35 for the adapter from Norton Racing (Adapter Kit: GSXR Shock to Kawasaki Ninja 400 / Z400 - Norton Motorsports).

They have a spring rate chart here for whether you should go for the GSXR600 shock or one from the 750 or 1000 (they both use the same 600 lb spring according to the info here): Suspension Spring Rate Chart - Norton Motorsports

On a budget, this is probably one of the better bang for buck upgrades.
 

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He's been banned, and for good reason.
Some one like racetech should be able to help you. I think your money would be better put towards an adjustable shock out of a GSXR or such like rather than spending it on a new spring for the stock shock which is very 'budget' in its performance and degree of adjustment.
i have now a re-vamped stock shock - after i test it i will post it
 

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Excited, I got my 4hundy about 8 weeks ago, and I'm slowly converting it to the track. OEM Bodywork removed and sold fairly cheaply. I've added a full Yosh exhaust, re-flashed the ECU& added new Velocity stacks. The Forks have been removed and are currently with my suspension guy. He is putting AR-25 Axxion Rod Damper Kit, S41-2 - Traxxion Dynamics in the forks. I'm still waiting on track bodywork that was ordered Dec 18th. Next up rear shock?? GIXXAH 600 one??? Suggestions??
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Street Test

Preliminary:
Tested the new spring for the rear Ohlins shock. Went from a 100 N/mm to a 95 N/mm.
Ride height: stock
Front sag: 34 mm
Rear sag: 32 mm
Spring preload: 12 mm
Compression adjuster: 12 clicks out
Rebound adjuster: 12 clicks out
Tyre: stock size, Bridgestone S22
Tyre pressure: 28/32 psi

Measured sag was done once with cold suspension oil, I know that is not ideal. With about half tank of gas. Should of done three measurements for sag, particularly when the suspension oil is hotter and with the same amount of gas to get a good average. Rider weight 155 lbs. naked.

Findings:
The softer spring made a noticeable difference in rideability and bump absorption of road imperfections. Turn in is more smoother and precise. Lateral steering changes side to side is sharper and quicker. When braking, there seems to be a smoother weight transition, thereby aiding in better turn in for sharper turns. It is impeccable at holding lines at bends. The biggest plus was the better absorption of the bumps and divots on the road. This is great for the street.
I also found that on launches, the rear will squat a tiny bit more than with the stiffer spring. Not a big deal though.

I was giggling like a school girl thinking this setup is suited to a crazy road race like Isle of Man.:p
I'll continue further testing...
 
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