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Different clutch slave cylinder sizes?


Stray

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Hello All, 

 

Does anyone know how the clutch space piston size of our VFRs (and other Hondas) changes over the years? 

 

I know a few numbers:

- 5th gen clutch slave is 35.6mm

- VTR1000 clutch slave is 35.6mm (I’m assuming as same part number)

- 6th gen clutch slave is 33.5mm

Oberon clutch slave is 38mm

 

Not sure if all 6th gens are same across the years? What about 8th gen? What about other Hondas with the same type of slave? CBRs, Blackbirds, Pan Europeans etc? 

 

I’d like to fit a bigger piston slave on my 5th gen but don’t know which one (other than Oberon).

 

As as an aside, if you’d like a softer clutch on your 6th gen you may want to try a 5th gen slave. You’ll get longer lever travel and more modulation. 

 

Best,

 

Stray

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12 hours ago, JZH said:

Don't forget that one of the few changes Honda made to the Y2k 5th gen was an upgraded clutch system...

 

Ciao,

 

JZH  

 

9 hours ago, Marvelicious said:

Interesting... if the info I'm getting from the parts fiche is right, they changed to the later springs and master cylinder, but the slave cylinder stayed until the 6th gen. 

That fact has had me spinning for months. Aftermarket clutch disc suppliers often list the same item for 5.1, 5.2 and 6th gen bikes. Some offer different part numbers. Not sure what to make of this. 

 

I think they changed more than the clutch springs as basket has different part number (if memory serves?). Different number of discs too (again, if memory serves?). 

 

I’ve often wondered if a 6th/8th gen clutch can just be dropped into a 5th gen. 

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Aren’t the 5.1 part #s for clutch pack superseded to 5.2 or even 6G?

Nope!

Many different part#s between 5.1 and 5.2, including friction & steel plates, center, pressure plate, and the cutch center. Outer is the same.

Both 5.2 and 6G use 2 different friction plates. They share the plate that takes 7, and the single different one is not the same. Outer baskets are different, inners and pressure plate are the same.

2002 and 2014 clutches appear to be identical.

They all have 8 friction plates; 7 of one, and 1 different. 5.1 has 8 steels, everything from '00+ has 7.

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The springs were just the only other part number I checked. The thinking was the springs are right up with the cylinder bores in what affects the feel of the lever. It seems likely that they changed other things as well. It also wouldn't surprise me to find that parts would interchange. 

 

Another quick look at the fiche... It looks like your 98 had 9 friction discs and 8 plates and it looks like they dropped to 8 and 7 in 2000. Less discs means less surface area to grab, so the heavier springs are to increase the clamping force. This isn't necessarily an improvement, unless you're working in the budget department at Honda.

 

I guess the question is whether or not you need more clutch to handle the power you have and the kind of abuse you're going to give it.

 

Hypothetically, if my goal were to build a clutch that can handle more horsepower, I would try to use the earlier basket with more discs but add stiffer springs and use our proposed cylinder mismatch to make up for the stiffness. If I'd never experienced any clutch fade, I'd probably just go with the earlier clutch though I might still go with the cylinder mismatch just to improve the feel.

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3 hours ago, BuzznerSuntrusts said:

They all have 8 friction plates; 7 of one, and 1 different. 5.1 has 8 steels, everything from '00+ has 7.

Are you sure you're reading that right? Looking at the fiche on Partzilla, I'm pretty sure I see 9 friction plates on the 98 model. 7 identical in the middle and a unique one on either side.

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2 hours ago, Marvelicious said:

Are you sure you're reading that right? Looking at the fiche on Partzilla, I'm pretty sure I see 9 friction plates on the 98 model. 7 identical in the middle and a unique one on either side.

Marvelicious is right: 5.1 has 9 friction plates. 7 identical in the middle and two different ones outside. 

 

Buzzner is also right - 8 steel plates for 5.1 gen. Also lots of different parts form 5.2, 6th and 8th gen. 

 

That’s 17 plates all together for 5.1 gen. 5.2, 6th and 8th gen appear to have 15 plates all together (please correct me if wrong?). 

 

Toro said the 6th gen had a better clutch for his supercharger but not sure if that’s down to stiffer springs? Theoretically the higher number of plates on 5.1 gen should be better. 

 

Not sure it really matters either way as VFRs don’t make the sort of power to overwhelm a gearbox. Apparently BMW S1000RRs are tearing chunks out of their gearboxes...scrap after 30k miles! 

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7 hours ago, Stray said:

Toro said the 6th gen had a better clutch for his supercharger but not sure if that’s down to stiffer springs? Theoretically the higher number of plates on 5.1 gen should be better. 

 

Not sure it really matters either way as VFRs don’t make the sort of power to overwhelm a gearbox. Apparently BMW S1000RRs are tearing chunks out of their gearboxes...scrap after 30k miles! 

I wonder if Honda didn't switch to a better material for their friction plates as well.

 

If I needed to rebuild my clutch for some reason, I would pursue it further. In the mean time, my 5th gen slave cylinder showed up... just waiting on the rebuild kit. It's in good enough shape that I could probably just drop it in, but since I'm in there...

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On 5/23/2019 at 4:49 PM, Marvelicious said:

Are you sure you're reading that right? Looking at the fiche on Partzilla, I'm pretty sure I see 9 friction plates on the 98 model. 7 identical in the middle and a unique one on either side.

I wasn't seeing the 3rd friction because it was numbered 20. I was just looking at the 7-8-9 that were grouped together.

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I just crawled out of the basement after swapping my 6th gen slave cylinder for a freshly rebuilt 35.6mm 5th gen slave. I haven't taken it for a spin yet, but just based on a gut reaction to the feel of it... oh yeah! We'll see how it rides, but I'm thinking this was a good move!

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Amazing work so far gathering information, but... What about the 4th gen? Can i fit an oberon slave on a 4th gen? Searching on their site they don't offer one, so i was wondering if i can fit a slave from another honda. I've found out TSR makes a slave for the rc30 that also fits on the rc45,rc51 and so on, but is so damn expensive.

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6 hours ago, davideb23 said:

Amazing work so far gathering information, but... What about the 4th gen? Can i fit an oberon slave on a 4th gen? Searching on their site they don't offer one, so i was wondering if i can fit a slave from another honda. I've found out TSR makes a slave for the rc30 that also fits on the rc45,rc51 and so on, but is so damn expensive.

Yes you can, same pattern.

 

I have a spare billet slave available for $100

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Hi Seb, thankyou very much, both information and the offer. I don't know how much would it be to have the slave shipped here to Italy because of border fees. The price by itself is really good.

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Hi FlyingToaster, i am currently discussing with Oberon, as they say they should have an option compatible for the 4th gen. They wanted some potos and the dimension of the slave. As soon as they respond i will let you know.

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10 hours ago, FlyingToaster said:

 

 

 

 

Sorry for question, but witch model of the Oberon Clutch Slave Cylinder is compatible with the VFR 750 4th Gen ?

 

VFR800Fi

RVF750R RC45

VTR1000 (RVT1000R) RC51 SP1/SP2   

 

 

 

As far as fit to the bike, they are the same. The difference is in the piston size. As discussed here you'll have to determine which size is best for you based on which master cylinder you're using and your desired feel/operation.

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16 hours ago, davideb23 said:

Hi Seb, thankyou very much, both information and the offer. I don't know how much would it be to have the slave shipped here to Italy because of border fees. The price by itself is really good.

 

Shipping is probably $24 or less, I can mark as a gift to save you the border fees. 

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On 6/29/2019 at 5:47 AM, SEBSPEED said:

Shipping is probably $24 or less, I can mark as a gift to save you the border fees. 

 Do you have any photos? I will let FlyingToaster have it if he is interested too.

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It's not all based on feel.  If you have a larger piston, it is easier but you have less travel.  Your clutch may not release fully and you will have hard shifting.

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In my mind that went without saying.

 

For anyone unfamiliar with the concept of mechanical advantage... Yes: Keep in mind that no reduction of effort comes without a similar reduction in travel.

 

I spent 8 hours on my bike today with the 6th gen master matched to a 5th gen slave. You couldn't pay me to switch back. YMMV...

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2 hours ago, Marvelicious said:

I spent 8 hours on my bike today with the 6th gen master matched to a 5th gen slave. You couldn't pay me to switch back. YMMV...

So, you and I are essentially running with the same setup? 1/2" master and 5th gen slave cylinder. Seems like I lucked into the butter zone with no research...😆😎:beer:

I found these 37mm and 38mm billet cylinders on ebay yesterday. Pretty, but very expensive! 37mm piston  38mm piston

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7 hours ago, BuzznerSuntrusts said:

So, you and I are essentially running with the same setup? 1/2" master and 5th gen slave cylinder. Seems like I lucked into the butter zone with no research...😆😎:beer:

I found these 37mm and 38mm billet cylinders on ebay yesterday. Pretty, but very expensive! 37mm piston  38mm piston

Well, butter isn't all that good for you... I can't find a down side to this combo.

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On 7/8/2019 at 6:36 AM, BuzznerSuntrusts said:

So, you and I are essentially running with the same setup? 1/2" master and 5th gen slave cylinder. Seems like I lucked into the butter zone with no research...😆😎:beer:

I found these 37mm and 38mm billet cylinders on ebay yesterday. Pretty, but very expensive! 37mm piston  38mm piston

Oberon is also very nice, and less than half the price of the TSR.

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