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/7 Clutch upgrade on a /6 bike

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Andey
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Joined: Wed Sep 02, 2020 12:45 am

/7 Clutch upgrade on a /6 bike

Post by Andey »

Got inspired by a message on my clutch, but has anyone attempted to install a /7 newer clutch on an older /6 bike?

I imagine its not that simple and a plug and play, but is it? Balancing the clutch pack seems to be a major point of note...

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schrader7032
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Re: /7 Clutch upgrade on a /6 bike

Post by schrader7032 »

RealOEM shows the clutch parts for my /7 were used up to 1980 and includes all bikes from 1970, so I think it is plug-n-play. As for balancing, I wouldn't worry too much about that...I believe each part comes balanced from BMW.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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srankin
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Re: /7 Clutch upgrade on a /6 bike

Post by srankin »

As Kurt says, from what I can see from the parts fiche, the clutch parts are the same for your /6 as for the early /7 bikes.

You are not by chance asking about switching to the system used in the 80 and newer bikes are you?

The clutch assembly and flywheel and perhaps the actuator rod are vastly different for the newer bikes.

From your threads on the post, you are fairly new at working on the bike. I can only tell you my airhead shop a few years back mated an early 77 engine to a 85 transmission. In doing this, there was a LOT of fiddling about with the clutch and flywheel assemblies in order to get them to play nice together. The results were good but getting there was not easy.

The 80 and newer bikes do have a better clutch system and as a result, they shift smoother and easier, this may also be internal to the transmission. Part of it is due to the lighter flywheel, Snowbum, I am sure will have something to say about it.

If it were me, I would stick with the stock system and ride it.

If you are not talking about what I just blathered about, never mind. St.
Owner of a 84, R80RT and 78, R100RS

Andey
Posts: 117
Joined: Wed Sep 02, 2020 12:45 am

Re: /7 Clutch upgrade on a /6 bike

Post by Andey »

srankin wrote:
Wed Sep 16, 2020 8:01 am
As Kurt says, from what I can see from the parts fiche, the clutch parts are the same for your /6 as for the early /7 bikes.

You are not by chance asking about switching to the system used in the 80 and newer bikes are you?

The clutch assembly and flywheel and perhaps the actuator rod are vastly different for the newer bikes.

From your threads on the post, you are fairly new at working on the bike. I can only tell you my airhead shop a few years back mated an early 77 engine to a 85 transmission. In doing this, there was a LOT of fiddling about with the clutch and flywheel assemblies in order to get them to play nice together. The results were good but getting there was not easy.

The 80 and newer bikes do have a better clutch system and as a result, they shift smoother and easier, this may also be internal to the transmission. Part of it is due to the lighter flywheel, Snowbum, I am sure will have something to say about it.

If it were me, I would stick with the stock system and ride it.

If you are not talking about what I just blathered about, never mind. St.
That’s exactly what I meant... the newer style 3 arm pressure plate. Not the same flywheel but from a later model... (I’m sure that’s something common place nowadays...)

I was looking into a lightened flywheel setup, but then the notion of using the newer style clutch came into some research... it would make sense to be able to upgrade, but I would be pretty sure there must be some caveat to all this...

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srankin
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Re: /7 Clutch upgrade on a /6 bike

Post by srankin »

Well to be honest, I would not bother with such an upgrade. I really don't think the change in operation is such to justify the cost and messing about.

From my end of the issue, I can understand the desire to have a smoother shifting, easier clutch to use, I know the difference between the system you have and the newer system because I have an example of each in my garage. The older bike with your system is a bit fussier to shift then the newer bike. But it is not that big a difference. I really don't see a difference in the clutch pull effort between the two bikes.

If there is a problem with the clutch pull, there is a device called I think and ez clutch. Mac, Kirkpatrick just did an article on it in the Vintage news magazine. It is far cheaper than a new flywheel, and clutch parts.

FYI, I have read the articles and forum threads regarding changing the ATE front brakes on my RS to Brembo brakes. While I can see and feel the difference between the two systems, I have yet and most likely will never do the swap. The cost is more than the gain. Now, if I rear end someone or have to replace the front end of my bike and need all new parts, well then maybe I would go and change to Brembo brakes. I know it has nothing to do with your clutch, it is just a further thought.

Lots of guys spend big money on their airheads to gain small results. Believe me, I am tempted many times to do things to my two bikes to up the HP and torque, I haven't because the cost is not worth the gain. St.
Owner of a 84, R80RT and 78, R100RS

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Re: /7 Clutch upgrade on a /6 bike

Post by schrader7032 »

You would need to replace the transmission in order to get the post 1980 clutch. I highly doubt it's worth the expense.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

Andey
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Re: /7 Clutch upgrade on a /6 bike

Post by Andey »

schrader7032 wrote:
Wed Sep 16, 2020 7:56 pm
You would need to replace the transmission in order to get the post 1980 clutch. I highly doubt it's worth the expense.
Swapping the transmission out isn’t really an upgrade... it’s more like a transplant...!! that doesn’t seem ideal...

From with I’m envisioning, it doesn’t seem worth it unless I had several bikes broken up.

Andey
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Re: /7 Clutch upgrade on a /6 bike

Post by Andey »

srankin wrote:
Wed Sep 16, 2020 6:24 pm
Well to be honest, I would not bother with such an upgrade. I really don't think the change in operation is such to justify the cost and messing about.

From my end of the issue, I can understand the desire to have a smoother shifting, easier clutch to use, I know the difference between the system you have and the newer system because I have an example of each in my garage. The older bike with your system is a bit fussier to shift then the newer bike. But it is not that big a difference. I really don't see a difference in the clutch pull effort between the two bikes.

If there is a problem with the clutch pull, there is a device called I think and ez clutch. Mac, Kirkpatrick just did an article on it in the Vintage news magazine. It is far cheaper than a new flywheel, and clutch parts.

FYI, I have read the articles and forum threads regarding changing the ATE front brakes on my RS to Brembo brakes. While I can see and feel the difference between the two systems, I have yet and most likely will never do the swap. The cost is more than the gain. Now, if I rear end someone or have to replace the front end of my bike and need all new parts, well then maybe I would go and change to Brembo brakes. I know it has nothing to do with your clutch, it is just a further thought.

Lots of guys spend big money on their airheads to gain small results. Believe me, I am tempted many times to do things to my two bikes to up the HP and torque, I haven't because the cost is not worth the gain. St.
Yeah it seems like one of those things which you would challenge with lots of time and didn’t mind having an inactive bike for a while to wait for donor parts...

I don’t think marginal gains is worth it on classic bikes... don’t think it’ll be high on the agenda of enjoying the bike...

Besides entertaining the experiment of trying, doesn’t seem worth the time and money... shame that...

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srankin
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Re: /7 Clutch upgrade on a /6 bike

Post by srankin »

LOL the various forums are full of guys doing all sorts of things to "improve" their bikes.

I have, I admit done improvements myself. Minor stuff such as a heavy duty top fork plate, front fork brace, LED tail light and head light bulb. Since I use heated clothing, I upgraded both my bikes to a higher output charging system.

The R80RT on its last engine rebuild got rebuilt with 9.5 to 1 pistons instead of the 8.5 to 1.

Other than the above improvements, the bikes are stock. The only complaint I have is the R80RT could just have a bit more power when passing cars. I know I could build it to match the power of the RS but, the need is rare and not enough to justify the cost.

I mention the fellow who mated the 77 engine to a 85 bike. He listened to some of the "wise men" on the forums and ended up doing things the hard way and it cost him more money. That is another story, I am getting carried away. Cheers, St.
Owner of a 84, R80RT and 78, R100RS

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