2007 Rear Shock Upgrade

[Vansaki]

I have a 2007 Ninja 250. I am 5'11 and weigh 205. I'm already planning on different springs for the front shocks. I would like an opinion on rear shock upgrades. I know there are several used shocks from other motorcycles that will fit and be good for my weight. Which ones are good to use? Thanks for any suggestion anyone may have .

Thanks !

[Triple Jim]

The simplest solution is to install a rear shock from a newgen 250 (2008-on). I did that and it did just what I needed.

[Vansaki]

Ok Jim. Thanks for the advice ! Very appreciated.

[Triple Jim]

For the front springs, I went with Sonic.

[Vansaki]

According to my weight, the sonic front springs I would need are the
0.85 kg/mm springs. I have never changed front springs on a motorcycle before so I was wondering what brand and weight spring oil to put in them. I don't race my bike. I just zip around town and maybe a few miles through some curvy country roads.

Thanks !

[Triple Jim]

There's some information about forks here: https://faq.ninja250.org/wiki/Front_suspension_upgrades

Sonic's instructions are helpful too: http://sonicsprings.com/catalog/damp...ch_article.php

They should send specific instructions with the springs. Fork oil is nothing magic. I'd just use what Sonic recommends, and ask them if the instruction don't say. Getting the oil level correct for your application is important though, and can take some trial and error in some cases. When I used the oil level they recommended it was good, but more will make the front feel stiffer.

Stock, my front end would bottom out on a very hard stop. That's bad, and it doesn't do that now.

[Shafer]

I have both my pregens replaced with ninja 300 rear shocks.

They are great compared to stock. 300 is just a drop in, easy 20 min job.

[thedrewski86]

Originally Posted by Vansaki

According to my weight, the sonic front springs I would need are the
0.85 kg/mm springs. I have never changed front springs on a motorcycle before so I was wondering what brand and weight spring oil to put in them. I don't race my bike. I just zip around town and maybe a few miles through some curvy country roads.

Thanks !

I ordered .85kg/mm springs from Sonic when I was setting up my '05. They are hard... so much so that I am running one stock spring and one .85 which seems to work very well. At my heaviest, I was about 200, down to 180 now and that definitely makes a difference. ymmv. I believe the online calculators figured my spring weight a little on the hard side because the Ninja is not an overly front-loaded bike, which is to say it does not put a lot of weight on the handlebars. Years ago, when I set up my SV using the same calculator, I got springs that were too light but that bike has much lower clipons and more weight over the front. Take all that for what it's worth (maybe ??).

I am also using an old Ninja 300 rear shock and have found it to be okay. Since most of the rider's weight is over the rear on the ninjette, I have found the damping to be a little slow for my riding; it gets pogo-ish in the fast, bumpy stuff. The 300 shock is cheap though, and a direct bolt-in. For the $80 I spent it was well worth it. I will no doubt replace it with a YSS in the future though.

[InvisiBill]

Based on RaceTech's calculator, .85 is good for 260-285lb depending on track vs. street. For 205lb, they suggest something in the .70-.75 range. https://www.ninjette.org/forums/showthread.php?t=231171

I had a NewGen shock on my 500 too. It's a great drop-in swap if the spring rate matches your weight. These are all really basic, non-serviceable shocks, so they're nothing special in that regard, but it is a cheap and easy respring if it works for your weight. https://www.ninjette.org/forums/show...02#post1023302

[Vansaki]

OK. I looked at Race Tech front springs. You are right. At my weight, Race Tech says to go with .75 springs and Sonic says to go with .85 springs. Should I split the difference and go with .80 Sonic springs ?? lol

Thanks!

[Triple Jim]

Originally Posted by Vansaki

OK. I looked at Race Tech front springs. You are right. At my weight, Race Tech says to go with .75 springs and Sonic says to go with .85 springs. Should I split the difference and go with .80 Sonic springs ?? lol

Thanks!

I think that if I were in that position, I'd go with .75. If it's a little too soft, you can add oil and get a little extra from the resulting compressed air. I say this because I have experience with some manufacturers specifying spring rates on the high side, probably because it's less likely to result in returns. After all, bottoming forks are going to cause springs to be returned.

On the other hand, I'm pretty sure you'd be safe with .8.

[InvisiBill]

I would trust RT's numbers over Sonic's. But you can also increase a spring's rate by cutting it shorter - a shorter lever requires more force to move. I think .75 will be good for you, but if you do end up needing it firmer, you could trim the spring to accomplish that.

.75 springs are 70.5% stiffer than the OEM .44 springs. That's about how much stiffer the springs for my EX500 were, and it was a night and day difference. Going from stock to .75 is fixing a major deficiency. Moving around a notch or two from there is just tweaking for perfection. Most people will benefit more from improving their own skills at that point compared to making tiny hardware adjustments to the bike.

[Shafer]

So I can tell you my setup and experience I have.

I'm 176 lbs with my gear on. When I bought and installed the .85 I was 200-210. So now I'm at the low end of the springs spec. I haven't notice a big difference with my lower weight.

07 - blue - sonic spring - .85 - Maxima 15WT - oil at 130mm - ninja 300 rear shock - 100/130 90 - BT46 tires.

07 - black - sonic spring - .80 - Maxima 15WT - oil at 130mm - ninja 300 rear shock 100/130 80 Shinko

I rode both bikes yesterday. And I'm sticking with .85 the bike is a apex hunter in the corners, super fast flicks, really wants to lean effortlessly and zero fork dive when front braking. Bumps are slightly stiffer no complaints. Smooth on the highway. Plus if I am touring I can comfortably carry extra weight.

Black rides nice also but has a slight fork dive under hard braking. Not bad, and no where as bad as the oem springs. Bumps are a little bit smoother, definitely a littlebit more plush feeling over the NH roads. But corners seem a little slower and relaxed. Still fun, but not the holly sh^t as blue in the corners.

Tires also might make a difference first season on both since springs were done. Total 5 start to the bt46. Rode Shinkos last season.

Either way you will be happy with new springs. I upgraded blues springs when I bought the bike because of a leaking fork seal. I rode black for the first time at the end of the season with the oem shock and I couldn't believe the fork dive and terrible ride. Rode like a rocking horse.

If you are dropping in springs spend the money and change all the seals with new kawi parts.