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Discussion Starter #1
Hey Guys,

I have a 2005 RC51. Absolutely LOVE the bike.

I've noticed that when the bike is warm, and I shift up, the gears really click hard into place. I don't know if this is normal for these bikes or not but I cringe every time i shift.

Shifting down is pretty smooth because I blip the throttle. Really need your guys' advice and input before I start freaking out and take it in to get it looked at. :(

Thanks in advance!
 

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How many miles on your oil change? Mine starts shifting hard after about 2K in this hot weather so I change it and all is fine.
 

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The 1st to 2nd shift can be slightly clunky due to clutch mass, but 2nd to 6th on mine is silky smooth. One of the best gearboxes I've used, at that's with over 36K miles on it.

When I switched my steel drive plates over to aluminum Hyperplates, the 1st to 2nd shift became a non-issue due to the reduction of clutch mass.
Too bad they don't make them anymore. It really made shifting wonderful.
 

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How many miles on your oil change? Mine starts shifting hard after about 2K in this hot weather so I change it and all is fine.
+1 I change my oil very often (1,800 ~ 2,200) depending on how hard I have ridden.

Its expensive but well worth it in the long run. I have sold several bikes I have owned since they were brand new. The folks who know me and my maintenance habits are waiting in line to buy these bikes when I decide to sell. (And they know I ride these things to my limits...)

Get into a good maintenance habit now, you will only benefit and appreciate the rides that much better.
 

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Discussion Starter #5
Hey Guys,

Thank you very much for the input. I think its about time to get an oil change. I bought the bike back in December and put about 1,500 miles on it. The previous owner said he had put about 2K since the last oil change. So I guess its about time I get this done. I will update you guys as soon as I get the oil change.

Thanks again!
 

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The 1st to 2nd shift can be slightly clunky due to clutch mass, but 2nd to 6th on mine is silky smooth. One of the best gearboxes I've used, at that's with over 36K miles on it.

When I switched my steel drive plates over to aluminum Hyperplates, the 1st to 2nd shift became a non-issue due to the reduction of clutch mass.
Too bad they don't make them anymore. It really made shifting wonderful.
I wonder if titanium and the clutch plates materials would be compatible? I wonder what your aluminum plates look like now?? Reverse engineering is not out of the question for me...
 

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I wonder if titanium and the clutch plates materials would be compatible? I wonder what your aluminum plates look like now?? Reverse engineering is not out of the question for me...
So far they're holding up pretty well.
I understand what I'm dealing with, so I try and hook up the clutch with as little slippage as necessary.
I also understand that nothing lasts forever, and that one day the hard anodizing will wear.
My choices there will be to either try and have them hard anodized again (or apply some other treatment), or go back to the steel plates (which I kept just for that reason).

Just to illustrate the weight difference, a set of 6 OEM steel drive plates weigh 590 gm, while a set of 6 Hyperplates only weighs 215 gm.
That's 65% less mass that has to be spun up or down during shifting.

It's too bad they're not made anymore, because they really improved the ease of shifting.
 

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so did you change the oil yet ? some times its that easy
 

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Discussion Starter #9
Unfortunately not yet... Got an appointment for Sept 10th at a local honda dealership. I guess they're really busy... wait list is almost a month out.

Having another problem now... the front brakes feel really spongy. I can squeeze the level all the way to the grip. I haven't rode in almost 3 weeks... rode today and they were like that. There is fluid in the reservoir. Could this happen with the bike just sitting there for 3 weeks?
 

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Subsailor,

Not trying to make you wrong, but the driveplates on a clutch are only a small proportion of the total weight being driven round on the same shaft. You have the clutch basket, shaft, gears, etc. too. So it's not really 65% less mass.

Regarding brakes - sounds like you might have some air in the system.

So far they're holding up pretty well.
I understand what I'm dealing with, so I try and hook up the clutch with as little slippage as necessary.
I also understand that nothing lasts forever, and that one day the hard anodizing will wear.
My choices there will be to either try and have them hard anodized again (or apply some other treatment), or go back to the steel plates (which I kept just for that reason).

Just to illustrate the weight difference, a set of 6 OEM steel drive plates weigh 590 gm, while a set of 6 Hyperplates only weighs 215 gm.
That's 65% less mass that has to be spun up or down during shifting.

It's too bad they're not made anymore, because they really improved the ease of shifting.
 

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Subsailor,

Not trying to make you wrong, but the driveplates on a clutch are only a small proportion of the total weight being driven round on the same shaft. You have the clutch basket, shaft, gears, etc. too. So it's not really 65% less mass.
As a part of the total clutch assembly, you're correct.
The drive plates do make up a smaller portion of the total weight, the clutch basket making up the majority.

But when the clutch is disengaged to shift up or down, the clutch basket no longer has an effect.
Then only the mass of the drive plates and clutch hub pertain.

In that regard, a 65% reduction of rotating mass on the main shaft enables easier shifting.

Since the clutch basket is always connected to the primary gear, its mass counts as a part of the overall flywheel mass.

Together, a lighter clutch basket would the engine to rev up or down quicker, while lighter drive plates allow the easier and smoother shifting.

That's why I was disappointed to learn a while back that Durbahn no longer made his lightweight clutch basket.

Some have also removed their flywheels and milled off a small amount of material to reduce flywheel mass and allow quicker revving of the engine.
 

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Thanks for the further explanation, Subsailor - Hadn't thought of it as simplified as that.

The gearbox is still being driven by the wheel when the clutch is disengaged and the bike's in gear though - it's just the engine that's disengaged from the gearbox - or in other words the gearbox isn't under load, so another gear can be selected, right?

Comparing with say putting a lighter clutch cover and smaller flywheel on a sports car I've never noticed an improvement in gear-change quality as a result, which is why I'm intrigued.

I find my SP2 box works very sweetly. I can't remember having had a false neutral in a very long time, so for me the box is working fine with no need to improve it.

I think properly rev matching when coming down gears and being smooth with both up & down shifts helps maintain a smooth running transmission and negates the need for things like a slipper clutch kit. The only mod I think a standard SP2 should really need for the transmission is something like 15/41 sprockets, but maybe we should save this discussion for another thread. Sorry, didn't mean to hyjack this one. :)
 

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Thanks for the further explanation, Subsailor - Hadn't thought of it as simplified as that.

The gearbox is still being driven by the wheel when the clutch is disengaged and the bike's in gear though - it's just the engine that's disengaged from the gearbox - or in other words the gearbox isn't under load, so another gear can be selected, right?

Comparing with say putting a lighter clutch cover and smaller flywheel on a sports car I've never noticed an improvement in gear-change quality as a result, which is why I'm intrigued.

I find my SP2 box works very sweetly. I can't remember having had a false neutral in a very long time, so for me the box is working fine with no need to improve it.

I think properly rev matching when coming down gears and being smooth with both up & down shifts helps maintain a smooth running transmission and negates the need for things like a slipper clutch kit. The only mod I think a standard SP2 should really need for the transmission is something like 15/41 sprockets, but maybe we should save this discussion for another thread. Sorry, didn't mean to hyjack this one. :)
The difference I notice is the 1st to 2nd upshift.
The gear ratio jump there is greater than the rest of the ratios.
The advantage of the aluminum drives plates is the ability of the main shaft to more quickly change rotational speed due to less mass, and this allows quicker engagement.

It's hard to describe, but the before and after differences are noticeable.
Before, the 1 to 2 shift worked fine, but you could feel a larger clunk than afterwards.
Just those fewer grams of mass spinning at x number of RPM make it a much better shifting gearbox.
 

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Intriguing indeed Subsailor. Thanks for taking the time to elaborate.
Shame titanium's so expensive... would have been nice to use a set of those instead of Stainless steel :)
 

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I was having problems with a violent clunk into first and the clutch jamming up.I checked the clutch plates and it seems the last owner who told me he had put new plates in, put the last plate in wrong,this and it would seem the oil I was using.Put the clutch back in the right way and changed to my regular oil which is mobil 1 4t, and the problem was solved.
 
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