I'm planning on getting a rear sprocket replacement soon, and was looking around to see what was available. I found one on Motorcycle-Superstore.com that looks cool and is supposed to be lightweight. My problem with it is, it looks pretty thin in a few places. Is this sprocket really strong enough? I'm planning on getting a 42 tooth.

http://www.motorcycle-superstore.com/1/5/85/21023/22736/PITEM/Parts-Unlimited-520-Lightweight-Rear-Sprocket-2007-Kawasaki-Ninja-250R-Parts.aspx

Interesting. It does look thin to me, but if it's going to survive on any bike, our bike is certainly the one it's going to survive on. I'd see if you can find out how long they've been offering that design, and/or see if you can find someone else who has had one for awhile. I think it probably would be fine, but I also think I'd have the same questions you have right now.

Good idea........ Except, how am I supposed to find that out? I'm fairly certain they won't tell me who's ordered one from them before!

I'd start with google searches of that particular model number...

Go with JT Sprockets or Sunstar if you are unsure. Both of those companies have good reputation for good sprockets. I just ordered a 15T front sprocket from JT and new, slightly taller tires (100/90/16)! I can't wait for the revs to come down a bit and my speedo to be more correct at higher speeds...

Well, I found the main page for this sprocket at Parts-Unlimited.com, and the picture doesn't make it look nearly as thin. It also talks about high grade, hardened steel. It doesn't give a steel grade though (i.e. 1024 carbon steel, etc.). I'll keep looking, but it's what I've found so far.

http://street.parts-unlimited.com/18/346/7981690

The only other thing I found that I thought had something to do with this was an add for what looks like the same sprocket, but from a different company and for the CBR1000. Here's the link to that (actually a front and rear sprocket + chain package). I don't know if this helps, but it looks like the exact same sprocket and it seems to work for a 1000cc bike, so why not for a 250?

http://www.solomotoparts.com/product.php?productid=32789

If you're still unsure about it what about looking into the sunstar sprocket? Looks to be similarly light weight but possibly stronger and close in price.

Sunstar 520 sprocket. (http://www.motorcycle-superstore.com/1/5/85/18219/22736/PITEM/Sunstar-520-Steel-Rear-Sprocket-2007-Kawasaki-Ninja-250R-Parts.aspx)

The only other thing I found that I thought had something to do with this was an add for what looks like the same sprocket, but from a different company and for the CBR1000. Here's the link to that (actually a front and rear sprocket + chain package). I don't know if this helps, but it looks like the exact same sprocket and it seems to work for a 1000cc bike, so why not for a 250?

http://www.solomotoparts.com/product.php?productid=32789


You did notice the massive price difference right? I hope you weren't suggesting to get that one instead?

I've had excellent wear from JT Sprockets over the years, on a variety of cycles. I use the steel ones, as their weight isn't an issue for me and I prefer the increased life from the steel sprockets.

You did notice the massive price difference right? I hope you weren't suggesting to get that one instead?

The massive price difference you're talking about is because it's a front sprocket, rear sprocket, and a chain all at once. And no, I'm not using that one. It's for a CBR1000.

Biggest reason I was looking at this sprocket is looks. I really like the way it looks, but if it's going to break on me, I don't want to mess with it. I'll probably go with something else if that's the case. :rolleyes:

It may work out fine, but I'd stick with something a little beefier. That's just me though...the weight savings and cool factor are going to have a minimal affect.

My understanding is that if you're going to change one of the three components (front, rear, or chain) it is best to change all 3 at once. The chain and sprockets all sort of wear into each other, and if you were to just change one of them, you are at risk for more rapid wear to all of the components. This is one reason why you tend to see sprockets and even chains so often sold in complete sets.

I'm planning on switching all of them out at the same time, along with brake pads and rotors (not sure on the rotors yet), and tires.

I'm planning on switching all of them out at the same time, along with brake pads and rotors (not sure on the rotors yet), and tires.

How many miles do you have on your bike?

A little over 7300. Probably don't need to replace brakes yet, but they've been feeling kinda weird lately. Also, the front rotor (the one that has been feeling weird) has a strange mark on it. It almost looks like a burn. I'd get pics, but I have to go to work. I'll try and post some tomorrow. Tires need a change because their the stock dunlop pieces of crap, not to mention the tread is almost gone. Sprockets because I want taller gearing, and chain to go with the sprockets.

A little over 7300. Probably don't need to replace brakes yet, but they've been feeling kinda weird lately. Also, the front rotor (the one that has been feeling weird) has a strange mark on it. It almost looks like a burn. I'd get pics, but I have to go to work. I'll try and post some tomorrow. Tires need a change because their the stock dunlop pieces of crap, not to mention the tread is almost gone. Sprockets because I want taller gearing, and chain to go with the sprockets.

Brake replacements depend on how you ride...my fronts lasted until 17,000 because I engine brake alot and travel mostly highway miles. Get some pictures of that rotor, it should last way more than 7 thousand miles barring extreme circumstances. You could also still be ok with the chain unless it's been severely neglected. Check for wear on the rear sprocket and chain, and if they're ok, slap a new CS sprocket on and call it dealt with for now.

Problem with the chain is, it really hasn't been well taken care of. I'd like to hope that it's ok, but I didn't know how to take care of it until recently, and I have no idea whether the original owners even cleaned it. Figured I'd stick on the safe side and get a new chain and just take care of that one really well, and not risk breaking the one I have even if I am taking care of it now. Nearly all of my riding is in the city... Again, I'll try to get pics of the rotor tomorrow.

Sounds like you're on the right track...

Ok... I got a picture of the rotor. It didn't come out too well though. The area I'm worried about is on the right side of the picture. It's circled in red on the second picture.

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Is that scrape/burn looking mark on the rotor a problem or is it normal?

Looks like a warped rotor to me.

I honestly can't tell much from the pic...does it feel warped when you brake? i.e. Do feel a pulsing from the front brake when in use?

cooked bro

I honestly can't tell much from the pic...does it feel warped when you brake? i.e. Do feel a pulsing from the front brake when in use?

That might be a way to say it. What I do feel, and only when braking at slow speeds, is almost like a rough spot on the caliper. The slightly dark spot I'm talking about is wierd. It feels a bit rougher, and the blackness rubs off a bit. Is it just dirty or is that a sign of a warped rotor? I guess you could say it does pulse some, and it makes a slight scraping sound.

You need another rotor.

Ok... I got a picture of the rotor. It didn't come out too well though. The area I'm worried about is on the right side of the picture. It's circled in red on the second picture.

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Is that scrape/burn looking mark on the rotor a problem or is it normal?

Before you buy a new rotor, take some good soap and scotchbrite (the maroon colored works good) pad to it and see if it cleans up. The most common cause for the rotor discoloration and/or brake pulsation is brake pad material build up. This is also misdiagnosed as "warped rotor" too. Put a little elbow grease into it and see how it turns out.. it's cheap to try :thumbup: Oh... scotchbrite the entire rotor... not just the discolored area!

Ummm, that rotor is no good. Unless you don't really use your front brakes.

The rotor will probably clean up and be ok. If he tries it and the dark area "comes off" then he saved some bux.

Any other opinions? I'll definitely look into cleaning it up before I buy a new one, just to be sure. If I do end up having to replace it, do I need to buy a brand new $300 one or can I get a used one off ebay? :confused:

Yep, I'd definitely give cleaning it a shot.

If you can rub bits of it off with your hand, that doesn't sound like heat blueing from a warped rotor constantly rubbing.

What happens when you centerstand the bike and get the front wheel off the ground (have someone sit on the seat) and spin it. Does it stop, or slow significantly when the discolored part hits the pads? That would happen if the disk is warped enough to have a rubbing problem.

Okay, I'll try that too. We'll see what I can find out. ;)

Yep, I'd definitely give cleaning it a shot.

If you can rub bits of it off with your hand, that doesn't sound like heat blueing from a warped rotor constantly rubbing.

What happens when you centerstand the bike and get the front wheel off the ground (have someone sit on the seat) and spin it. Does it stop, or slow significantly when the discolored part hits the pads? That would happen if the disk is warped enough to have a rubbing problem.

Great idea Bill, you ought to get a pretty solid answer to whether or not it's actually warped or just discolored by trying this.