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Old July 14th, 2018, 12:30 PM   #81
DannoXYZ
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Originally Posted by DannoXYZ View Post
Yes, it does work because spring-stiffness is based upon number of coils. The more coils you have, the softer the spring (because each coil defects same amount given any load).. By removing some coils, you stiffen the spring. Usually removing 100mm is good amount on these bikes. Then adjust pre-load by using 105mm or 110mm PVC spacer.
Whoops, forgot there's already 100mm spacer in fork. So you may not need to shorten spring very much to stiffen it up. Perhaps start with just 50mm chop and make up difference by replacing stock 100mm spacer AND your chopped amount with PVC. So make 150-160mm spacer. Similar to what Maverick's done here:

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Old July 14th, 2018, 01:46 PM   #82
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Quote:
Originally Posted by InvisiBill View Post
You can actually calculate how much to cut off the spring to give a desired rate.

new spring length * new spring rate = original spring length * original spring rate

If the stock spring is 450mm long (that's just an example - don't actually use that number) and 0.65kg/mm, that gives you a total value of 292.5 for the stock spring. If you want it to be 0.75kg/mm, you just divide by that and get a new length of 390mm. For 0.85kg/mm, you'd end up with 344.1mm. If you want to get really precise and go for 0.7945kg/mm, cut it down to 368.16mm.

The only downsides to cutting springs are that it's a permanent mod, and if you're really heavy, you may not be able to shorten it enough without interfering with operation of the spring (obviously you can only cut off so much length before it doesn't work in the fork).

You'll need spacers to make up for the removed length of spring. The "extra" length of spacer in the fork tube (in either stock or modified form) is what creates preload. That's probably not the correct setting from the factory, and it will necessarily change when you change the spring rate. You'll probably have to tweak the length of your spacer to get the correct preload/sag setting. ProTip: It's easier to trim off a little than it is to add a little back - start longer and shorten it.

If you have the preload properly set on the stock spring, you can compare the total length of the spring & spacer to the total length of the fork's spring chamber to figure out how much force it's applying on the spring. You can then use that to adjust your spacer length to give the same force on the new spring's rate.
or 85 dollars gets you a set of sonic springs.
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Old July 14th, 2018, 02:56 PM   #83
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or 85 dollars gets you a set of sonic springs.
But saving that can get you other upgrades! Such as

1. Free fork upgrade + new chain
2. Free fork upgrade + jet-kit
3. Free fork upgrade + flush-mounts+led flasher+diodes
4. Free fork upgrade + clip-on bars + fender delete
Etc.
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Old July 14th, 2018, 07:28 PM   #84
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guys I'ma leave off the fork and shock upgrades until I feel the need for them.. I'm not experienced enough or pushing the bike enough yet.. no track days for me so riding on the street and going ramping hasn't really got me thinking about it for immediate upgrade but for the future list.

I DO however need some help with carb/jetting!

I have Aliexpress slip-on exhaust (Baffle was on.. but took it off for now)
K&N hiflow air filter (installed by one of the previous owners)

Today.. I finally took the bike to DIY shop to install DYNOJET stage 2 kit along with size 40 pilot jet. (Stock size at 38) Also changed out spark plug to NGK CR8EIX (iridium or whatever..)

Installation was huge pain in the rear and omg... that airbox...

Got rid of Snorkel as instructed.
Installed the provided needle along with 96 size dynojet main jet as I wanted to keep the baffle on the slip-on. (I believe size 96 was recommended for stock exhaust..)
Installed 40 pilot jet.
drilled out mixture screw cap and seated at 3 turns out as instructed from the bottom.

Issue now is that it seems to be running too rich on the low end as it's slow on the pick up when I turn the throttle hard.

Should I go back to stock pilot jet or is there other way to fix the issue?
I feel it should be alot more responsive..
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Old July 15th, 2018, 03:55 AM   #85
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put the 38's back in, the 40's are just too much gas on the botton end. i tried em for a year on my red bike until danno xyz coaxed me into trying 38's again. 40's only need 1 turn out. if you have stock header, you don't need a jet kit. a couple of shims under the needles and your done. i just swapped my el cheapo full system to godzilla and it runs great. uni filter/2 shims under carbs. stock airbox/snorc removed. i had to put baffle in after 10 miles(too loud and it seemed to like the backpressure)
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Old July 15th, 2018, 04:00 AM   #86
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sticks r us

if ya want cheap, do stick coil mod.
https://www.ninjette.org/forums/showthread.php?t=300352
https://www.ninjette.org/forums/show...9&postcount=62
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Old July 15th, 2018, 07:16 AM   #87
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a good tool

if ya gonna play with pilots, this really helps out. made by motion pro.
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Old July 15th, 2018, 08:59 PM   #88
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I need to follow your el cheapo thread thoroughly... I do want to put the baffle back in..it's too damn loud and if I could remove the airbox and go with pod filters, that be amazing! only thing I won't be able to swap out is the stock header atm. Mechanic friends got all giddy and excited once the prospect of possibly machining a custom header was suggested but had to tell him to calm down.. haha

so... currently I have
Stock airbox/K&N Hiflow filter ---> Carb (40 pilot, Dyno 96 mainjet and needle shimmed with provided kit) ---> stock header ---> cheapo exhaust (baffle out)

Hoping to get to

Airbox removed w/pod filters --->Carb (whatever setting that will work best) ---> stock header ----> cheapo exhaust (baffle in)

is this a possibility dynojet stage 2 kit? or is the stock header hinderance to the performance? I don't mind riding this season out and getting something like Tyga or Hindle next season if above is a possibilty.
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Old July 16th, 2018, 08:04 PM   #89
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I got the R6 throttle tube, it's a bit of improvement. I got clip-ons and rear-set adjusters which I really like. I also upgraded my weak brakes, but a nice upgrade would be the Racetech Springs and rear shocks.
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Old July 17th, 2018, 07:17 AM   #90
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Quote:
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I got the R6 throttle tube, it's a bit of improvement. I got clip-ons and rear-set adjusters which I really like. I also upgraded my weak brakes, but a nice upgrade would be the Racetech Springs and rear shocks.
R6 throttle tube upgrade is installed already

Clip-ons, rear set, springs and shocks are on the wanted list for the future. I do mostly city riding so those would be a luxury. If I do track in the future, then it be first on my list of to-do I guess.
Got EBC sintered brakes.
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Old July 26th, 2018, 08:44 PM   #91
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valve adjustment

it's happening...
mechanic friend is checking on the valves on my bike and pretty much all 4 shims on exhaust side were out of spec. Inlet was fine tho..
only at 16000 km and out of spec already..



Stripped down.. again...


had to remove one of the radiator bracket thingy to remove the valve cover


I don't really have any clue on these stuffs but will learn about it one day i guess..


the circled numbers are what we got after measuring the exhaust side.

rejetting the carb tomorrow.
Going back to stock pilot jet to see if it will make it run better/consistent
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Old July 28th, 2018, 01:40 AM   #92
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Originally Posted by jp8484 View Post
rejetting the carb tomorrow.
Going back to stock pilot jet to see if it will make it run better/consistent
Here's the thing: why is it not running well? It did when it left factory with stock jetting.

We see it all the time, someone has running problems with their bike stumbling. Probably lean mixtures at some operating zones. So what do they do? Punch bigger holes in their carbs and it runs better! Then some time goes by and it starts running crappy again. So what do they do? Punch even bigger holes in carbs again! And again!

This is only covering up symptoms, not fixing actual cause of problems. Whenever dealing with carb problems, you should always start from common baseline, which is factory-fresh brand-new clean carbs. Bike ran perfectly fine when new with factory jetting, so why isn't it running perfectly now?

That's why i always have a perfectly clean factory-fresh set of carbs as testing-control i can swap in as test. It will always run perfectly fine with factory jetting. Which tells me what??? Problematic carbs are CLOGGED and needs complete tear-down with ultrasonic cleaning, flossing of all secret passageways and soda blasting. THEN, they miraculously work as well as factory-fresh clean carbs with factory jetting.

When I have time, i'll link to threads where people have had to pull their car and clean them 4-5 times before they got to factory-fresh clean condition.
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Old August 1st, 2018, 11:45 AM   #93
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Quote:
Originally Posted by DannoXYZ View Post
Here's the thing: why is it not running well? It did when it left factory with stock jetting.

We see it all the time, someone has running problems with their bike stumbling. Probably lean mixtures at some operating zones. So what do they do? Punch bigger holes in their carbs and it runs better! Then some time goes by and it starts running crappy again. So what do they do? Punch even bigger holes in carbs again! And again!

This is only covering up symptoms, not fixing actual cause of problems. Whenever dealing with carb problems, you should always start from common baseline, which is factory-fresh brand-new clean carbs. Bike ran perfectly fine when new with factory jetting, so why isn't it running perfectly now?

That's why i always have a perfectly clean factory-fresh set of carbs as testing-control i can swap in as test. It will always run perfectly fine with factory jetting. Which tells me what??? Problematic carbs are CLOGGED and needs complete tear-down with ultrasonic cleaning, flossing of all secret passageways and soda blasting. THEN, they miraculously work as well as factory-fresh clean carbs with factory jetting.

When I have time, i'll link to threads where people have had to pull their car and clean them 4-5 times before they got to factory-fresh clean condition.
Thanks Danno!
I really just wanted bit more pull on the lower end without having to worry about stalling..

When the carb was pulled, it was in a really good condition inside actually.. inspected all the jets and holes etc. Main and needle got replaced anyway.

Currently it's back to stock pilot (38) with base setting recommended by Dynojet. I called Dynojet and dude was helpful but no real info I could use to tune it better.. other than him telling me I should get a bigger bike as weak low end is characteristic of these smaller displacement bikes.. haha what a guy.. (Street hawk TV show reference.. if anyone is watching that on Amazon prime, the original squid)

will be pulling the carb out again this week or next and work on it with butt dyno.. probably will put the 40 pilot back in and try to lean it out with mixture screw or float bowl or something and maybe put Dynojet 94 main.

Also having issue with idle being rough (set at 1.3k) but no throttle hanging issue.. will have to check for vaccum leak or something.
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Old April 25th, 2019, 07:46 PM   #94
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thank you!

Hey you amazing people on this forum
it's been a minute but wanted to stop by and say hello and good bye for now!

I ended up selling my Ninja 250 this February and picked up 1994 Yamaha FZR 600 due to my long term illness of obsessing over twin round headlight look of that era. FZR needed some TLC so ended up opening up the top end to do some refresh and still got lots to do...

Just wanted to tell you guys that you guys been amazing and extremely helpful to someone who is new to a motorcycle!
Riding is definitely the most fun aspect but meeting, sharing, and learning from those you meet along the way just about make this the best experience EVER! haha

I do miss my old ninja... spent a lot of time riding and learning on that bike. When wife allows more than one motorcycle in the stable.. i'll definitely be looking at another small displacement motorcycle that I can rev the hell out of with big grin on face.

ride safe out there guys!
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Old April 25th, 2019, 08:09 PM   #95
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No need to run off if you don't want to.

(wife allows?)
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Old April 25th, 2019, 08:48 PM   #96
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No need to run off if you don't want to.

(wife allows?)
I'll lurk around!

and yeah going by the mantra 'happy wife, happy life'. seems to be working out so far.. also have a small one car garage so i can't fit another bike in there when i got current project bike and parts bike for it in there..
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Old April 26th, 2019, 06:28 AM   #97
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... also have a small one car garage so i can't fit another bike in there when i got current project bike and parts bike for it in there..
That's easy, just put one in the kitchen. I know a guy who had a milling machine in his.
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Old April 26th, 2019, 11:36 AM   #98
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That's easy, just put one in the kitchen. I know a guy who had a milling machine in his.

I have a 3 H.P. outboard motor in my living room and two more in my bedroom but the milling machine has me beat.

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Old April 26th, 2019, 12:32 PM   #99
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I had my brake caliper in my kitchen while we worked on it, but yeah, the milling machine has me beat.
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