Sprockets, Sprockets and more Sprockets
The big trend here in the Ninja 250R world is Mod First — Sprocket later… Most guys are finding that after adding exhaust, intake, and jetting that the bike is under geared for the new available power. In stock skin, the 2008 Ninja 250R is a gear ratio of 3.21 or 14/45 (14 Tooth Front / Counter shaft sprocket — 45 Tooth Rear / sprocket) and the most common mod now is to replace the front sprocket with a 15 tooth for 15/45 setup or a gear ratio of 3.00 (7% increase in gearing).
As of now the JT Sprocket from Dennis Kirk is the most popular (In fact it’s now sold out) — However after some research I have found a bunch of alternatives. It seems that the late model EX250 and EX500 sprockets fit the 2008, and manufactures are just now updating their fitment lists. So, If you have a favorite sprocket manufacture — Email them for fitment and availability.. And if you have any luck leave us a comment and I’ll try to keep the list updated.
Vortex Racing Sprocket Kit
Part Numbers: n/a
Fronts: 16
Rear: 44, 45, 46, 48, 49, 50 (Black)
Includes new Chain
Price: ~150$
Sunstar Sprockets
Part Number: 2-34714?
Steel Rear: 41, 42, 44, 45
Price: ~40$
JT Sprockets
Front Steel: 14, 15 [Part Number: JTF 486.??]
Rear Steel: 38, 39, 40, 41, 42, 44, 45, 47 teeth [ Part Number: JTR 486.?? ]
Rear Alloy: 43, 44, 45, 46, 47, 48, 49, 50, 51, 52 teeth [ JTA 486.?? ]
Price: ~20$ - ~50$
Supersprox
Rear: 39, 40, 41, 42, 43, 44, 45 (Gold / Black)
Price: ~80$
[ Product Details: Here - I lied, It’s actually Here - Thanks Nevar! ]
Matty E Said,
August 20, 2008 @ 6:06 am
For us Aussies that might be looking at the site and thinking of going down the sprocket change route remember the rear on our bikes is already 43..
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Nevar Reply:
August 25th, 2008 at 10:16 am
Really? Damn didn’t notice.
Anyways the real link for the super sprocket is http://www.supersproxusa.com/products.php?cat=1528. The link above is for the “motocross” 250.
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Mr. 2Fiddy Reply:
August 25th, 2008 at 10:56 am
Woops…. My bad… My Bad… Post updated… Thanks for the Heads up!
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Nevar Reply:
August 25th, 2008 at 6:54 pm
No problems, anything to help your site along.
Btw I think it should be me thanking you, not the other way around
*Tips his hat*
Reddoak Said,
September 26, 2008 @ 10:06 pm
Just put a Vortex Racing 43 took rear sprocket on the bike. It weighs about half what the stock piece did. Chain length was fine, and well within adjustable range. The bike is a bit less buzzy in traffic now, and 1st gear definitely is better when stuck in stop and go traffic.
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j Dizzle Said,
December 8, 2008 @ 12:09 am
just wondering if a new sprocket set would be good as a first mod or second mod as opposed to starting with the exhaust and intake; understanding this would be a prefrence question what would be the difference between the different parts.
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Obsidian Said,
June 18, 2009 @ 2:34 pm
I just tried to order that JT front 15 tooth sprocket using your part number and I got absolutely nothing on it. I tried several shops around the area and none of them are even showing a way to order it. The part number showed up as invalid on a couple of their computers.
Are you sure that is the right part number?
BTW, other than aesthetics, this is my first power mod. lol.
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Obsidian Said,
June 18, 2009 @ 2:41 pm
Just found this on the JT website.
Kawasaki EX250 F2-F19,F6F,F7F Ninja 250 R USA
1988 to 2007
Front Sprocket: JTF 516.14
Rear Sprocket: JTR 486.45
Alloy Rear Sprocket: JTA 486.45
Recommended Chain: : 520 / 106
Front sprocket available in: 13, 14, 15, 16 teeth
Rear sprocket available in: 38, 39, 40, 41, 42, 44, 45, 47 teeth
Alloy Rear sprocket available in: 43, 44, 45, 46, 47, 48, 49, 50, 51, 52 teeth
http://www.jtsprockets.com/52.0.html?&L=0&sel_uid=4593&p=
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Leo Said,
July 10, 2009 @ 10:56 am
want to go to this sprocket configuration. Commuter riding. hope to decrease highway rpm ( now 7000 rpm =64 mph) and pick up a little more mpg. Will I need a new chain (by the way, what is the link count in the stock chain)?
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Ninja Rider Said,
July 18, 2009 @ 11:04 pm
There is so little info on a 16t front sprocket for a Ninja 250, yet they do sell them. I went ahead and bought one, since I love my 15t, I figure I will also love the 16t. Has anyone put a 16t front sprocket on a Ninja 250? If so, we would appreciate to know if anything needs grinding for clearance. Like the cover or anything.
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JMcD Said,
October 20, 2010 @ 11:00 pm
I am running the JT 16t front and 41T rear sprockets on my 2008 250R. I wanted longer gears for a “smoother” feel. Second gear is within about 1% of stock 3rd, and 4th gear is a few% shorter than stock 6th. Top speed is now reached in 5th gear (4th goes to 101 at redline, but the stock engine won’t pull that high, and shifting to 5th adds several MPH). The front sprocket did require me to grind about a millimeter out of the sprocket cover to keep the chain from rubbing.
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