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R75/6 Clutch 1976

cseltz

Member
In the process of a rebuild and find that the clutch plates have a fair amount of rust (bike sat outside under a cover for a couple of years before I got it). It looks like it will clean up pretty well with emory cloth but I am wondering just how "smooth" the surfaces have to be to function properly. I would rather not the expense of a new clutch if I can avoid it. The thickness specs on the disc and the measurements on the spring are all well within spec. Thoughts?
 

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What can hurt?? If the clutch doesn't work out, you'll know it soon enough or down the road and you'll just have to remove and do it with new(er) parts. If you're doing it all yourself, you only have your time to lose.
 
I'd try to clean them up using a really flat surface if you can. If you don't want to risk that wd40 has a new product you can soak them in that will dissolve the rust.
 
Just go ahead and use them. The rust will disappear after a few applications of the clutch. Works no different than a drum brake. The reason for the rust is the steel on the pressure plate. Any of them sitting in the air will rust, that's just the nature of the beast.
 
If it were mine, I'd take the time to clean off the rust - I used a 3M non metallic scotch pad to scrub with brake cleaner - worked wonders.
My 2c
 
Time to replace clutch?

My clutch is showing signs that the end is nigh, about how much time should I budget for the job?

TIA
 
Parts in hand, it should easily be done in a weekend. I don't have the stamina to push through a job, so I would split it up...one day/afternoon to disassemble and clean, a second day/afternoon to reassemble. I like the additional time to think about what I'm doing and mentally go over the steps to be sure I didn't forget something.

You will need a few special items, like the allen wrench to properly torque the swingarm pivot pins in addition to a good torque wrench...you need ft-lbs and in-lbs. Also, you'll need three long bolts to slowly release the tension on the clutch pack as well as putting it back together. A few people recently have discussed the clutch installation and the need for a clutch alignment tool...so far I've not needed one but it could same some hassle.
 
Another really good remover of rust ... Barkeepers Friend. It contains oxalic acid which loves rust. I use it on my /5s steel bits (axles, nuts, band clamps, etc.) every month or so. And it can't be beat in the kitchen.

Half and hour with BK, water, and a Scotch-Brite pad and you'll be done.

200px-BarKeepersFriend.jpg
 
What are the signs (how do you know the clutch needs replacing)?

Barron

On my last ride, on a steep uphill in top gear, the clutch began to slip. I've about run out of cable adjustment and the clutch engages right at the start of the lever pull. Are my assumptions incorrect?

Thanks
 
On my last ride, on a steep uphill in top gear, the clutch began to slip. I've about run out of cable adjustment and the clutch engages right at the start of the lever pull. Are my assumptions incorrect?

Thanks

Assuming that it's adjusted correctly, that sounds like clutch slippage. If you ease off the throttle, clutch should "catch", and allow a gentler acceleration. It might also require a lower gear when under the increased load to remain "connected".
 
If you ease off the throttle, clutch should "catch", and allow a gentler acceleration. It might also require a lower gear when under the increased load to remain "connected".

That's what was happening. As soon as I could pull over, I adjusted the cable and am now out of threads on the barrel adjuster.
 
I recommend the "Tom Cutter" method for clutch cable adjustment. It's in the reference thread in my sig line. I did it and found it to give me a better and positive engagement.
 
I should have been more clear, my question was to get some more info from Justin in the hopes thar if he described the clutch symptoms in more detail, it might turn out to be something less than a clutch replacement.

The recommendation to start with Tom Cutter's adjustment procedure is really good. That seems to solve 75% of the problems that start out looking like a clutch replacement.

Barron
 
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