Rojoracing53 front suspension setup for racing

[rojoracing53]

So this is in general because it will work for all three ninjette's since all forks are linear.

So here all the info no one seems to know or I couldn't find

OEM fork setup
Spring
Rate 0.629
Spring length 420mm
Coil diameter 4.2mm
#of effective coils 31
Spring diameter 30mm

Spacing
Fork height 12mm above triple at the front
Fork top - Cap top =4.82mm( .190" )
Cap depth =14.6mm( .575")
Uncompressed spring + washer = washer depth below fork top =2.5mm( .100")
Preload Spacer length = 100mm(3.938")
Top Washer thickness= 1.57mm(.062")

Spacer
Length = 100mm(3.938")
I.D. = 1.065
O.D. = 1.125

Washer
Length = .062
I.D. = .870
O.D. = 1.180

So what the hell does all that mean will if you had payed attention it would mean the OEM preload is 22mm and is just above the recommended preload range of 10-20mm which wouldn't be bad if your light enough with it to get proper sag #'s but that's not the case for me.

So before ordering springs from RaceTech I wanted to figure out what rate I needed, I don't trust RT online calculator in the slightest and for reference so you know why, they calculate me as needing a 0.70kg spring(wrong)

I called up RT and talk to I think Terry at ex#110, he's one of their techs. I discussed my doubt of the online calculator, my base setting on the stock front end and what I'm looking to achieve with it. After 40 mins on the phone with him we determined that the 250 and new 300 use the same spring rate from the factory .63kg. Also with the stock preload at 22mm(kinda high) and my sag at 44mm without gear(way to much) we opted to try .80kg springs with 10-20 mm of preload.

He also described that the kit comes with two small springs installed in the emulators as well as a spare set. The yellows are for racing so they are stiffer and the blues are for street riding and are softer. You can adjust the preload on the emulator springs with the screw that holds them in place with 2-6 turns. These turns of preload will act similar to the turns of compression dampening on a higher end bike cartridge front end. The only way to adjust your rebound dampening is with oil density so they suggest you start with 15wt and if you go up to 20wt it will be like adding a few clicks to you rebound dampening. By changing oil wt. you also affect the compression. Since you can adjust the compression with the preload on the spring you should focus on getting you rebound speed corrected then start to playing with the spring preload to dial in your compression speed. I'm running 20wt now to but I feel my rebound may be a little slow so I think ill try 17.5wt(20 in one fork and 15 in the other) and a few more turns on the yellow spring preload to get back the loss in compression dampening from the lighter oil.

After receiving the parts from RT I installed the .80kg springs with 10mm of preload, oil level at 130mm using 15wt. oil, yellow springs with 4 turns of preload. With this setup I still had 41mm of sag so I tried 20mm of preload and that brought sag to 33mm. Now 33mm isn't bad but that's using the 20mm of preload which is at the recommended high range and I still haven't even put on my 15-20lbs of gear yet so the sag # is only going to increase.

So I called up Terry at RT and gave him the #'s and setting I had thus far and after some chatting he suggested I try .90kg springs. So I get the .90kg springs installed with 15mm of preload and my sag "with gear" is 31mm, finally a perfect sag #. I hop off the bike and with me standing next to it and with the front brake on I give it a few bounces. The front end just seemed to be moving to freely for my taste so I swapped the 15wt oil for 20wt and gave it a few more bounces. The front end moves much slower now and resembles what the bounce of my old Yamaha race bikes would look like. I also raised the fork tubes all the way up into the stock clipons to get a lower ride, this changed the 12mm setting above the triple clamps to 14.9mm.

I was not able to ride it in the street to get a feel for it before heading to the track but I felt confident that it had to be better then stock.

Now on track through the turns the bike seems to be riding high in front when I'm on the throttle so normally I'd try backing off a bit on the preload to get it to sag a bit lower through the turn. But in this case I didn't because I know that my rear shock although it has the correct sag, it has way to much preload in it to achieve that sag so when you apply force through a turn my rear sags a lot more then the front. You could do one of two things.

1. Buy a stiffer rear spring for the stock shock so you can get the correct sag #'s using an amount of preload within the suggested range(not sure what that range is just yet).

2. buy an aftermarket shock and like option 1 get the correct spring rate and sag #'s.

During the two days of track riding at Laguna Seca I was able to push the zip tie on the front end to within 4mm of bottoming so I'm using all the travel without hitting the bottom which is what I was going for. The bike felt solid on the brakes even when I was slamming them on at the last second to late braking other riders. I had zero cases of front wheel chatter like I did at Chuckwalla last year and in general I had no complains with the new front end setup which is amazing considering how critical I am. Because the suspension felt so good right from the start I did not setting changes like I had planned and opted to just enjoy riding for the weekend.

I was able to ride the bike to and from work yesterday on my normal commute and found I use all but 25mm of travel so I think I could probably go a bit softer for the street but I think ill go for a ride up and over Mt. Hamilton before I decide to change anything.

Next on the list is a GSXR rear shock but to be honest the bike feels fine on the street with the stock shock so it may be awhile before I get around to getting that done.

I know I may have gone a bit back and forth in this post but it was written over three days in my free moments at work on my phone so your just going to have to read the whole thing and try and absorb it as a whole.

If you have any questions feel free to ask and I'll answer what I can and lie about the ones that I can't

[rojoracing53]

Holy **** I had to re-read that over 3 stints just to keep from falling asleep and there's most likely still spelling errors

[Dmented]

good write up tho!

I'm also rocking the .90 kg springs with 15WT oil at 130. preload's 8mm but i get maaaaaaaaaaad mid corner chatter. i'm working on getting rid of that.

[broken neck]

Hell Yeah...

Clear enough for me, excellent work...

Thanks!

This will help me a lot...

[rojoracing53]

Originally Posted by Dmented

good write up tho!

I'm also rocking the .90 kg springs with 15WT oil at 130. preload's 8mm but i get maaaaaaaaaaad mid corner chatter. i'm working on getting rid of that.

Dude your like what 30-40lbs heavier then me a running a slightly softer setup stiffen that bitch up

[rojoracing53]

Originally Posted by broken neck

Hell Yeah...

Clear enough for me, excellent work...

Thanks!

This will help me a lot...

Yeah sorry I didn't get it out sooner but better late then never right

[Somchai]

Very good and useful informations.

Maybe the pdf can help a lil bit and please note the spacing should be app. 12mm above triple.

[rojoracing53]

Originally Posted by Somchai

Very good and useful informations.

Maybe the pdf can help a lil bit and please note the spacing should be app. 12mm above triple.

Sorry you right its 12mm where they tell you to measure it but it is 10mm at the front because the triples are square. If since corrected my point of measurement and changed it to 14.9 which is the maximum you can raise the tubes into the stock clipons. I also noted that with 14.9 when the forks are bottomed you have exactly 7mm of clearance between the front fender and front fairing so dropping the front end much more would not be advised.

[Motofool]

Hey @Alex,

Can we make this a DIY?

[Dmented]

Originally Posted by rojoracing53

Dude your like what 30-40lbs heavier then me a running a slightly softer setup stiffen that bitch up

i thought the same thing... but they just gave me 10wt oil to try and get rid of the chatter...


also, how many holes are drilled in your emulator's?

[rojoracing53]

Originally Posted by Dmented

i thought the same thing... but they just gave me 10wt oil to try and get rid of the chatter...


also, how many holes are drilled in your emulator's?

Just the original two

I'm thinking that they may need to be just a hair smaller or I could try opening up what ever controls our rebound just a little so I could run something heavier then 20wt. For the compression without totally stopping the rebound. It's to bad I don't race more often because this stuff could use a lot more testing at full race pace

[Dmented]

Originally Posted by rojoracing53

Just the original two

I'm thinking that they may need to be just a hair smaller or I could try opening up what ever controls our rebound just a little so I could run something heavier then 20wt. For the compression without totally stopping the rebound. It's to bad I don't race more often because this stuff could use a lot more testing at full race pace

i only have ONE... one hole drilled out...
some people have all four drilled, like this shot.


whats yours look like?

[dino74]

Just for reference, whats your weight?

[sharky nrk]

Great thread

[rojoracing53]

Originally Posted by Dmented

i only have ONE... one hole drilled out...
some people have all four drilled, like this shot.


whats yours look like?

I have two holes on opposing sides and two divots that don't go through. Divots are so you know where to drill if you want to add holes. If your only has one hole I'd say someone missed it production.

For reference I'm 160lbs without gear.

[broken neck]

Originally Posted by rojoracing53

Yeah sorry I didn't get it out sooner but better late then never right

I should have asked my questions earlier then... héhéhéhéhéhéhéhéhé...

It's never too late... I might not have the ultimate superweapon for this week end, anyway I'm so far from being an ultimate rider anyway... But I'll try to adjust and figure out later for my street riding...

[Alex]

Originally Posted by Motofool

Hey @Alex,

Can we make this a DIY?

/linked from DIY thread

[Motofool]

Originally Posted by Alex

/linked from DIY thread

[Jiggles]

Well its not a REAL DIY yet. So how about this, Jason, I'll order all the parts for my bike and let you install them for me and I'll make a DIY video out of it And then it will be a real DIY

[csmith12]

Originally Posted by Jiggles

Well its not a REAL DIY yet. So how about this, Jason, I'll order all the parts for my bike and let you install them for me and I'll make a DIY video out of it And then it will be a real DIY

+1

Waiting for the pics... lol

[rojoracing53]

Originally Posted by Jiggles

Well its not a REAL DIY yet. So how about this, Jason, I'll order all the parts for my bike and let you install them for me and I'll make a DIY video out of it And then it will be a real DIY

Hmmmmmm is this still in relation to that $60/hr thread

Ill think about it but I used a ceiling wench at the parents to do mine and I don't want to be working on other people's bikes over there. If we removed the front fairings we could probably get my front stand to work but I never tried. I'm sure we could come up with something.

[cuong-nutz]

Originally Posted by rojoracing53

Ill think about it but I used a ceiling wench at the parents to do mine and I don't want to be working on other people's bikes over there. If we removed the front fairings we could probably get my front stand to work but I never tried. I'm sure we could come up with something.

http://www.ninjette.org/forums/showthread.php?t=136034

[Jiggles]

Isn't the infamy of having your DIY video permanently attached to ninjette enough? Nah I'd be happy to pay for your services since you seem to know pretty much what the **** you are doing.

[rojoracing53]

Originally Posted by cuong-nutz

http://www.ninjette.org/forums/showthread.php?t=136034

Well hell I guess we have this handled then

[rojoracing53]

Originally Posted by Jiggles

Isn't the infamy of having your DIY video permanently attached to ninjette enough? Nah I'd be happy to pay for your services since you seem to know pretty much what the **** you are doing.

It's not about knowing what you talking about, its about sounding like you know what your talking about. Sounding like a genius while discrediting everyone else is the key to success in America

[csmith12]

Why is this thread in General?

[rojoracing53]

Originally Posted by csmith12

Why is this thread in General?

Did you read the top

It's because we don't have a general tech section that covers all three generations. Plus general gets the most traffic and I figure most people could benefit from this info.

[csmith12]

lol fail on my part, still not sure it applies to all gens though.

[Jiggles]

Originally Posted by rojoracing53

Did you read the top

It's because we don't have a general tech section that covers all three generations. Plus general gets the most traffic and I figure most people could benefit from this info.

I have suggested this same thing but it always falls on deaf ears

Originally Posted by Jiggles

Sure wish there was some general tech section to put this that wasn't limited to 250s hint hint wink hint wink

[Alex]

[cuong-nutz]

@rojoracing53 @choneofakind

Do the tapered bearing conversion affect the steering geometry? I recall reading something saying it lifts the front triple x amount.

[choneofakind]

The top triple gets pushed up a hair. Just from eyeballing it, I'd say less than 1/4", likely about 3/16"

[rasta]

Wow, I still have SO MUCH to learn about the technical side of motorcycles. Jason's OP made zero sense to me

[csmith12]

Originally Posted by rasta

Wow, I still have SO MUCH to learn about the technical side of motorcycles. Jason's OP made zero sense to me

So much knowledge comes as you need it.

[rojoracing53]

Originally Posted by rasta

Wow, I still have SO MUCH to learn about the technical side of motorcycles. Jason's OP made zero sense to me

Don't worry I wrote the damn OP and a year later I have no idea WTF I was talking about I will say my front end is smooth as butter at Laguna through the corners and stable under braking no matter hard I slam those things on.

As for tapered bearing changing the height of the triple? Well I'm currently in a state of I don't really give a **** about details and have been since last year after I perfected the front end suspension, so I don't know.

[subxero]

what is the total available travel of the stock front suspension?

[InvisiBill]

Originally Posted by subxero

what is the total available travel of the stock front suspension?

http://www.kawasaki.com/Products/Pro...?scid=6&id=553

37mm hydraulic telescopic fork / 4.7 in.

[Somchai]

I place my new experience under this thread since I think it's worth to bring it back to attention.

One of these days I met a guy from Ireland who'd for 20 years worked as a race mechanic on Kwaki bikes and his special knowledge is the setup of suspensions.
So I took the chance not only to ask him some questions but better get him correct my setup, what 2 experienced riders told me is good, but from my feeling I thought that it could be better (not so harsh).
The first thing he told (or to say teached) me is that one always must ride at least minimum 30 km (20 miles) before the suspension would work as it should and the reason for that is - the oil must reach its working temperature while before it always will feel to stiff (cold oil).
He'd ride my bike and found out that:
- at my front forks the rebound was not good, what made my forks slowly in returning from compressed
- the forks have been to stiff (also my impression of them).
His recommendation was to use 10W oil instead of 15W, what we changed,
also to raise the air gap which was to low (reason see below),
and as third point to readjust the blow-off force of the FEGV higher (from 1.5 turns to 3 turns).
The preload of the rear shock was to high also and this we'd adjust lower (from 9mm to 6mm).

Since here we don't get Putoline fork oil, which is what he said 'the best one can buy' we'd put Motul 10W oil into the forks.
By the way, I'd never think that after only 2 years and around 6500 km (app. 4000 miles) the fork oil would look like it did - pure mud.
After all the work was done and since I'd ride the bike now I can say - WOW, it's still stiff enough but feels complete different (way more smooth), not to only say better. My Ninja is going smooth over the waves on the roads here and cornering really is fun.
The problem here in the LOS is the different coating of the roads, since concrete is changing with tar and back again. Also from the big heat the roads are sometimes like waves with many big potholes in it also.
And one really important information for the usage of Gold Valves is the question, why does RT recommend 130 to 140 mm oil level?
After the FEGV's are in the fork the oil level raises by 29 mm (measured from my Irish specialist, while RT maybe calculates 30 mm), what I didn't think about before and maybe some of you didn't or don't also. And so at the end the level is back on what the service manual recommends.
If something isn't that easy to understand, please excuse, but english is not my native language.

[InvisiBill]

Just for reference, whats your weight?

@rojoracing53 Do you mind sharing this info? I'm curious how far off RT's calculator is, or if it's been tweaked at all since your work.

[rojoracing53]

I'm 160lbs