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Discussion Starter #1
Here's the story: i've owned my 2004 RC51 for about a year now, and I'm interested in changing the sprockets. I want to get into the power range a little sooner, have more grunt at lower speeds. i don't really care about top end speed-my Hayabusa can satisfy that need for me. I'm thinking about going to 15t front and 41t rear. So here's my questions:

1. Any tricks to getting to the front and taking it off? I can't seem to find any info on that.

2. Will the original chain still fit with this combo? The bike only has about 12,000 miles on it and the chain looks good--lots of life left in it.

3. Anything else I should know before taking on this project? i've changed chains and sprockets before so not a total newbie on this.

Thanks in advance to your help and advice!
 

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That is the same gearing I went with. As for taking off the front sprocket, you can do it easiest with the help of an air impact wrench. Once the retaining nut is off it slides right off the splines. You also won't need to break the chain but you'll have to work a little to get everything in position where it will slide off. The chain is very stiff laterally so it has to be in the right spot to let the sprocket come off. If I remember, I had to take the back tire off first so I could move the chain around. You won't have to force it, just get it lined up. My original 530 chain still fits fine. and I still have plenty of adjustment. I went with a SuperSprox rear sprocket. They are not the lightest but very durable. I'm not racing it anyway or I would have changed to a 520 setup. That gearing and a Power Commander made a world of difference in the rideability of my bike. I only had about 5500 miles on mine when I made the change so my chain was newer. If you're sure the chain hasn't stretched you'll be good.

BTW, If you could take it to a track you likely wouldn't lose any top end either. From what I've read they didn't pull to redline in 6th anyway so the gearing change doesn't hurt a stock bike at all.
 

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Discussion Starter #3
Hey TNR--thanks for the info. Since I'll be taking the rear wheel off to change that sprocket too, removing the chain won't be a problem. What has to come off to get to the front sprocket? I know there's a cover, but is there a slave piston for the clutch or anything I have to worry about in there? Thanks again!
 

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Yes, the sprocket guard and clutch slave both come off and from memory I think the share a couple of bolts. Also note which bolt goes where as they are different lengths. You don't have to drain the clutch just tie it up to the side. While it is off, don't pump the clutch lever. It's also a good opportunity to clear out the goo that collects. Otherwise, torque back to the correct level and it is actually pretty easy to do.
 

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Discussion Starter #5
Yes, the sprocket guard and clutch slave both come off and from memory I think the share a couple of bolts. Also note which bold goes where as they are different lengths. You don't have to drain the clutch just tie it up to the side. While it is off, don't pump the clutch lever. It's also a good opportunity to clear out the goo that collects. Otherwise, torque back to the correct level and it is actually pretty easy to do.
Thanks again. Yea, I was reading and it was suggest that the clutch level be tied to the bar in the fully disengaged position. I'm thinking that might be so the internal spring doesn't push the slave piston out of the holder. I might try that as well as taping the piston closed. Other than that it seems like a pretty simple job. Thanks for the info--I just wanted to make sure I was thinking about it the right way. Always nice to talk with someone who's already done it!!!
 

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Put the bike on a rear stand and either remove the rear wheel or loosen the axle and slide it as forward as possible.
Then remove the clutch cover, leaving the clutch slave cylinder attached.
If you have a small C-clamp, you can use it to press the slave cylinder piston to prevent it from creeping outward.

If you're going from 16/40 to 15/41, then usually no change will be needed on the chain.
If not, then you may need to remove or add links for what ever new sprockets are being used.
If your chain is in great or like new condition, then using it with new sprockets should be ok.
If your chain is not in good condition, the replace the chain as the chain is what wears out the sprockets (chains don't stretch, they wear).

Ryobi makes a great 1/2" 18V electric impact wrench that is more handy than air impacts (especially with the lithium battery).
It worked great on my daughters FZ6 countershaft sprocket.

 

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Discussion Starter #7
Put the bike on a rear stand and either remove the rear wheel or loosen the axle and slide it as forward as possible.
Then remove the clutch cover, leaving the clutch slave cylinder attached.
If you have a small C-clamp, you can use it to press the slave cylinder piston to prevent it from creeping outward.

If you're going from 16/40 to 15/41, then usually no change will be needed on the chain.
If not, then you may need to remove or add links for what ever new sprockets are being used.
If your chain is in great or like new condition, then using it with new sprockets should be ok.
If your chain is not in good condition, the replace the chain as the chain is what wears out the sprockets (chains don't stretch, they wear).

Ryobi makes a great 1/2" 18V electric impact wrench that is more handy than air impacts (especially with the lithium battery).
It worked great on my daughters FZ6 countershaft sprocket.

AWESOME! that's just want I needed. Thanks a bunch!
 

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I have no clue of the number,but I went with +2 in the rear and -1 in the front. It goes so fast. Hard too keep the front down on quick acceleration thou. Perfect for the track but not so much on the street. In Fl where I live it is a $1000 fine for 1 wheel of the ground.
 

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Discussion Starter #12
I have no clue of the number,but I went with +2 in the rear and -1 in the front. It goes so fast. Hard too keep the front down on quick acceleration thou. Perfect for the track but not so much on the street. In Fl where I live it is a $1000 fine for 1 wheel of the ground.
Yea--but they have to catch you first!!! LOL
 

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Don't "tape" the clutch slave. It will probably tear the tape. Just use a rag and a c-clamp. Pull the solve off before you pull the cover. That way you're not trying to loosen bolts that are probably factory tight with the cover in your hand. Usually not a big deal with small bolts, but you never know.

Also a perfect time to look at your clutch fluid. Since you are asking these questions, I am going to use my psychic abilities to tell you that your clutch fluid is dirty as hell and probably looks like coca cola. Perfect time to change it out.

+1 on the Ryobi impact. I have their cordless drill too. Both use the lithium batteries and are pretty good. There are some things that the impact won't get off when the battery isn't fully charged, but it usually still loosens them to where I can get it off by hand with a ratchet. The thing is awesome to have for tire rotations on the car, or anything really. You can also use a 2x4 in the rear wheel (as long as the chain is still on) to loosen the sprocket bolt.
 

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Discussion Starter #14
Don't "tape" the clutch slave. It will probably tear the tape. Just use a rag and a c-clamp. Pull the solve off before you pull the cover. That way you're not trying to loosen bolts that are probably factory tight with the cover in your hand. Usually not a big deal with small bolts, but you never know.

Also a perfect time to look at your clutch fluid. Since you are asking these questions, I am going to use my psychic abilities to tell you that your clutch fluid is dirty as hell and probably looks like coca cola. Perfect time to change it out.

+1 on the Ryobi impact. I have their cordless drill too. Both use the lithium batteries and are pretty good. There are some things that the impact won't get off when the battery isn't fully charged, but it usually still loosens them to where I can get it off by hand with a ratchet. The thing is awesome to have for tire rotations on the car, or anything really. You can also use a 2x4 in the rear wheel (as long as the chain is still on) to loosen the sprocket bolt.
Thanks for the info on the slave clutch. I'll be sure to do that. I've used the 2x4 method in the back wheel when I changed the sprockets and chain on my Hayabusa. IMO--much better way to loosen the front sprocket that leaving the bike in 1st gear as some guys do. I just don't like the idea of pulling against the gear. Yea, i'll probably change the clutch fluid while I'm at it. i don't think the guy I got the bike from ever did any of that stuff. I've already replaced the brake fluid and new coolant. Hope to get her all ready to go as soon as the snow melts!!! LOL
 

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I have no clue of the number,but I went with +2 in the rear and -1 in the front. It goes so fast. Hard too keep the front down on quick acceleration thou. Perfect for the track but not so much on the street. In Fl where I live it is a $1000 fine for 1 wheel of the ground.
I'm running that combo too, it's 15/42. I don't have any trouble keeping the front down. You can do a power-up wheelie in first and second gear fairly easy, but you have to be trying. Unless you normally accelerate wide open out of a stop, you won't have *trouble* keeping the front down. I've been running this combo for 2-1/2 years now. No track, 50% city commuting and errands, 50% hwy's and canyon roads.
I love this gearing for the way I ride my bike. It's easy to behave in traffic and shift points are more appropriate for the speed limits in any city.
 

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I've had front sprocket nuts really give me a hard time before on other bikes. Before you loosen or remove the rear wheel, step on the rear brake while popping the front sprocket nut loose. That way you don't have to be in gear and you don't have a 2x4 pressing against your rear wheel spokes.

I've used this method when I didn't have anyone to help me and when I didn't have a decent impact wrench.
 

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Discussion Starter #17
So here's another question bound to start some discussion:

Which do you prefer?

1. drop the front to 15t and raise the rear to 41t
2. Leave the front at 16t and raise the rear to 42t

Will either option have the same result?
 

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So here's another question bound to start some discussion:

Which do you prefer?

1. drop the front to 15t and raise the rear to 41t
2. Leave the front at 16t and raise the rear to 42t

Will either option have the same result?
Changing the front sprocket by 1 tooth is equivalent to 3 teeth on the rear.

I wouldn't prefer one or the other as your question poses, I would make that decision based on my chain length and how wheelbase and adjustability would be affected.
 

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I'm running that combo too, it's 15/42. I don't have any trouble keeping the front down. You can do a power-up wheelie in first and second gear fairly easy, but you have to be trying. Unless you normally accelerate wide open out of a stop, you won't have *trouble* keeping the front down. I've been running this combo for 2-1/2 years now. No track, 50% city commuting and errands, 50% hwy's and canyon roads.
I love this gearing for the way I ride my bike. It's easy to behave in traffic and shift points are more appropriate for the speed limits in any city.
DO THIS! i have the same combo 15/42 520 conv and its great! i am about 60% work (commuting) and 40% play.. lol
 
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