NSR125R Larger Front Sprocket Wanted ???

Annie · L Plate Warrior Joined: 25 Mar 2004 Karma :

Does anybody know where I could get a larger size front sprocket for my NSR125R (2002 uk model) ???

Bike is de-restricted now, ie, exhaust and intake, and is now hitting 100mph, but I would like to alter the gearing. Apparently need 15 tooth sprocket in place of 14 tooth, but can't find one anywhere.

Can anyone help???

p.s. don't really want to reduce rear sprocket / chain length if I can help it!

cagiva gezzer · World Chat Champion Joined: 17 Mar 2003 Karma :

www.biketorqueracing.co.uk
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"because one stroke isnt enough and four strokes waste two"

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Going to a 15 tooth sprocket will raise the top speed slightly, or more likely just lower the revs slightly while cruising. However you might still need to lengthen the chain.

If you use a smaller rear sprocket then you can take a link out of the chain if you need to. You cannot really safely add any links into the chain.

Going up one tooth on the front will change the gearing such that at the same revs it is currently doing in top to manage 100mph it would be doing 107mph (might not actually go that fast).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

Annie · L Plate Warrior Joined: 25 Mar 2004 Karma :

Tryed Bike Torque Racing and they don't stock a 15 tooth.

Does anybody know any where else that might have one ???

cagiva gezzer · World Chat Champion Joined: 17 Mar 2003 Karma :

www.mandp.com

Though their website is crap to say the least, try phoning them or looking through their book.

Or a local Honda dealer.
____________________
"because one stroke isnt enough and four strokes waste two"

G · The Voice of Reason Joined: 02 Feb 2002 Karma :

Not any help, but, if it was me, I'd go down a tooth if anything.

The NSR takes a while to get to it's Redline in 6th, so it aint going to be able to get that much further. You will also reduce it's not that great acceleration as well.
As Keith mentioned, you may not go any faster, because the engine may not be able to produce enough power to overcome the wind resistance; this will be worse if it's geared higher as well.

Going down a tooth would give you better acceleration and mean you get to a slightly lower top speed quicker.