Drive sprocket change - Honda RC51 Forum : RC51 Motorcycle Forums
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post #1 of 19 (permalink) Old 07-25-2019, 09:37 AM Thread Starter
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Drive sprocket change

I am about to move to a 15/42 sprocket setup and am a little confused about what to do with the clutch lever. Doesn’t seem to make sense to follow the workshop manual and ziplock it fully engaged when removing the slave. I would have thought this will fully extend the piston when the slave is disengaged from the shaft making the installation difficult, am I missing something here?
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post #2 of 19 (permalink) Old 07-25-2019, 09:59 AM
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the reason the manual says to zip tie it is to close the system. when the lever is pulled the ports to the reservoir are blocked. this means that the system is of fixed volume and the piston in the slave cylinder cannot move.

if you do not zip tie it, the piston in the slave will creep out (there's a spring inside that will push it out) and will draw fluid from the reservoir and potentially pull air into the system. this is the cause of all the "i changed sprockets and now much clutch doesn't work" posts. there are thousands of them because people didn't follow procedure.


to make installation easier, zip tie the lever, then crack the bleed nipple at the slave to bleed the pressure off. this will keep the piston in a resting position where it can't creep out, but it will also keep it at the retracted position, not the extended position, so putting the cover back on will be easy as you don't have to disengage the clutch with the cover going on.


then when you are done, before you release the lever, open the reservoir and carefully watch the level as you slowly release the lever. if the level goes too low simply top it up. (when you release the lever you must fill the master from the reservoir as the slave has been bled off)



simple as that really.
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post #3 of 19 (permalink) Old 07-25-2019, 04:23 PM Thread Starter
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Thank you Wibbly, this is the clearest explanation I have seen! There are a myriad of posts on this but none that I could find give a technical explanation. Do you have an opinion on the “Nicky” modification ?
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post #4 of 19 (permalink) Old 07-25-2019, 04:38 PM
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I think it's stupid. It's one of those things people do to say they've done it and put it on a mods list. It has nothing to do with Nicky Hayden anyway.

It's way easier to remove the cover to change sprockets. And you should remove the cover to clean inside anyway.
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post #5 of 19 (permalink) Old 07-25-2019, 05:02 PM Thread Starter
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Confirmed what I had been thinking! Thank you again
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post #6 of 19 (permalink) Old 07-25-2019, 07:16 PM
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and before everyone gets their panties in a knot, it's just an opinion.
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post #7 of 19 (permalink) Old 07-25-2019, 08:36 PM Thread Starter
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Quote:
Originally Posted by Wibbly View Post
the reason the manual says to zip tie it is to close the system. when the lever is pulled the ports to the reservoir are blocked. this means that the system is of fixed volume and the piston in the slave cylinder cannot move.

if you do not zip tie it, the piston in the slave will creep out (there's a spring inside that will push it out) and will draw fluid from the reservoir and potentially pull air into the system. this is the cause of all the "i changed sprockets and now much clutch doesn't work" posts. there are thousands of them because people didn't follow procedure.


to make installation easier, zip tie the lever, then crack the bleed nipple at the slave to bleed the pressure off. this will keep the piston in a resting position where it can't creep out, but it will also keep it at the retracted position, not the extended position, so putting the cover back on will be easy as you don't have to disengage the clutch with the cover going on.


then when you are done, before you release the lever, open the reservoir and carefully watch the level as you slowly release the lever. if the level goes too low simply top it up. (when you release the lever you must fill the master from the reservoir as the slave has been bled off)



simple as that really.
Hi Wibbly,
Apologies for being so anal but as part of my web surfing i came across a youtube video where no bleeding was done prior to the casing removal I asked the question as to why and have received this reply , does leaving the slave attached to the case change the need to bleed?
cheers
ps i think he is referring to the Rogue site
"@alan If you watch my video you see I only removed 2 of the 3 bolts holding the slave cylinder in place. What I generally did was remove the sprocket cover leaving the slave attached. Their was a little hydraulic (brake) fluid leakage but you have to bleed the system when its reassembled. I found this suggestion on the Roug RC51 forums and it worked. decompressing the cylinder is what was stated in the shop manual (I have one)"
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post #8 of 19 (permalink) Old 07-25-2019, 09:51 PM
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just remove the slave and cover together. you can leave the slave cylinder bolt that doesn't land on the perimeter of the cover.


if you bleed the pressure off (not bleed the whole system, just crack the bleeder at the slave after tying the lever to let the pressure off) then there is no force from the clutch springs against the slave during removal or installation.


the guy in the video did it wrong if there is any fluid exiting the system. you do not have to bleed after reassembly.


youtube is a cesspool of idiots trying to get attention. there are so many terrible how-tos on there. just like anywhere on the internet, people are free to say what they want, and unfortunately the loudest are often the ones we should pay not attention to.
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post #9 of 19 (permalink) Old 07-25-2019, 10:12 PM Thread Starter
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Thank you , there is as you say so much information out there most of it not peer reviewed and often containing a lot of "half truths" ---makes it difficult to get to the heart of the issue. I will be sticking to this site for advice from now on. YouTube has some use as you can view the topic, just need to be careful and cross reference to a reliable source ----like yourself!
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post #10 of 19 (permalink) Old 07-25-2019, 10:31 PM
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none of this is rocket science. you can do it any way you like.

i suggest taking the pressure off the system so you aren't disengaging the clutch when you put the cover back on. it makes things easier

honda says to tie the lever and then let the cover disengage the clutch because eliminates any messing around with the fluid.


either way is fine, but it IS important to close the system before you remove the slave. that's all.
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