Rear Sprocket removal - Honda CBR250R Forum : Honda CBR 250 Forums
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post #1 of 5 Old 10-13-2017, 01:41 PM Thread Starter
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Rear Sprocket removal

I have started the modification of my cbr by installing taller gearing for my hypermiling endeavors. I purchased a 15t front sprocket and a 36t rear sprocket. The front sprocket installation was easy but I see I will need to modify the cover. When I went to remove the rear sprocket I found that the nuts and bolts were very tight and I was starting to strip them when I applied more force. I researched this forum and found the trick is to use an impact wrench on the nuts rather than trying the loosen the bolts via the 6mm hex hole. My question is how do I separate the hub that the sprocket is attached to from the wheel. I had assumed it would just pull out from the cushdrive. Is there a hidden or some other attachment? Or is it just tight and I need to pry harder. Please let me know.
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post #2 of 5 Old 10-13-2017, 01:49 PM
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I did have had the cush drive apart to install plastic shims that I cut to take up the extreme free play, but don't remember anything in particular about that or the sprocket bolts.


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Last edited by sendler; 10-13-2017 at 02:57 PM.
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post #3 of 5 Old 10-13-2017, 02:52 PM
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I think heating the sprocket nuts may be required to avoid problems.

Not sure what the torque spec is on them, but be careful. My son just made a mess of his R6 sprocket carrier by trying to torque them to the recommended spec. I told him I thought it was too much - but the factory spec has to be right - right? Turns out it's pretty common to strip them when trying to get to the recommended torque. Not sure how they screw it up, but it was over what the standard torque is for that size of fastener. Shoulda listened to the Old Man...

Double check the factory spec with a table of standard torque specs for the fastener. Know that the size of the socket/wrench that is used does not tell you the size of the fastener. You need to measure the actual diameter of the bolt. You will get a diameter like 8mm, 10mm, 12mm, etc., for most sprocket nuts and bolts.

Vic - the sprocket carrier should pull out of the wheel. It may be snug, but I've never seen any type of retaining system used.
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post #4 of 5 Old 10-13-2017, 04:10 PM Thread Starter
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Jay and Scott, thanks for the quick replies! I couldn't imagine any additional retainer for the sprocket hub, thanks for confirming this.

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post #5 of 5 Old 10-14-2017, 01:12 AM
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When you reassemble it put some rubber grease on the rubber spider to aid the process of dis-assembly next time.

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