Lucas Clutch friction plates

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torp68
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Lucas Clutch friction plates

#1 Post by torp68 » Wed Mar 29, 2017 11:09 am

Anybody got any experience with these?
Bought them off eBay recently to swap for my tired, old ones.

http://www.ebay.com/itm/Lucas-Clutch-Di ... Ig&vxp=mtr

Trying to fit them in the basket went well, until I tried to fit item #19 (ring/cushion) in this drawing inside the first friction plate.
http://www.cmsnl.com/yamaha-rd500lc-198 ... ml#results

The Lucas disks have a smaller inner diameter, not leaving enough room for these "ring/cushions"....
The seller (UK-Motors) say this is the correct item for the RD500, but cannot answer me if I can use the plates without these rings.

Any thoughts? :???:

Oyvind

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Speed Freak
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Re: Lucas Clutch friction plates

#2 Post by Speed Freak » Wed Mar 29, 2017 1:07 pm

Maybe it is not planned to reuse this "cushion rings".
None of the modern bikes has this rings and on the RD350 the standard clutch disks are often replaced by clutch disks with smaller inner diameter from later Yamaha models (leaving out this rubber rings as they get hard and lead to a slipping clutch).

This cushion rings are meant to create an even distance between the steel plates of the clutch for a lower residual torque when the clutch is opened (better/softer shifting, lower wear in the gearbox).
But as said, modern bikes doesn`t have this rings - maybe because there is not really a difference if you are not using them.
It`s more important to deburr the contact faces of the clutch basket (between basket and clutch disks) and use the correct oil.
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda CBR 1000 RR SC57
Yamaha R1 RN04

torp68
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Re: Lucas Clutch friction plates

#3 Post by torp68 » Wed Mar 29, 2017 5:36 pm

Ok, thanks for a quick answer, Speed Freak.
I´m not working on modern bikes so had nothing to compare with :smile:

Oyvind

Honda NS400R
Yamaha RD500 1GE

BigGuy
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Re: Lucas Clutch friction plates

#4 Post by BigGuy » Wed Mar 29, 2017 9:17 pm

Sorry to hijack. Speed Freak, when you say "It`s more important to deburr the contact faces of the clutch basket (between basket and clutch disks)" do you mean smooth out all the marks left from the plates bearing on the large spline and corresponding tabs? If so how much material can be removed before it's an issue?

Thanks
Shake "N" Bake!

silverstrom
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Re: Lucas Clutch friction plates

#5 Post by silverstrom » Wed Mar 29, 2017 9:49 pm

Shawn

You need to remove enough material to make the face of each arm perfectly smooth. Over time the plates wear into the arms on the basket and you end up with a sticky clutch as a result. I use a sanding drum on a dremel tool. The issue you run into with this is that if you remove too much material on some arms of the basket you end up with some of the arms on the basket not touching the plates while others are tight against it. It's a trial and error process. If you remove a lot of material from every arm of the basket you end up with a lot of play between the plates and the arms. That theoretically shouldn't be a big problem as it only rotates one way, but you do run the risk of rapid wear when that gap is taken up when you launch. If the basket arms have a lot of wear it's best to replace it.

BigGuy
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Re: Lucas Clutch friction plates

#6 Post by BigGuy » Thu Mar 30, 2017 12:23 am

Thanks John, that makes sence. Basically take as much as needed but no more. At the the same time keeding the amount of stock removed as equal as possible.
Shake "N" Bake!

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Speed Freak
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Re: Lucas Clutch friction plates

#7 Post by Speed Freak » Thu Mar 30, 2017 3:58 am

Don`t take more material off as the clutch plates already did.
No need for a straight line but often there are burrs (inner edge of the arms) and also steps in the contact face, especially when the steel plates are mounted with the sharp edge facing to the engine.
This steps need to be removed and the lower edge needs to be deburred.

You can judge in which condition the clutch basket is from hearing.
There is a typical sound if the basket is worn, in idle (neutral) with closed clutch it`s rattling. When you pull the clutch the rattling noise will disappear.
Thats because the whole clutch plates are in one line clamped together by the springs and swinging from one contact face to the other due to torsional vibrations of the engine.
When you open the clutch the impact between clutch plate and basket is dampened as the weight of the main axle and the inner basket is decoupled from the clutch plates.

The more space between the parts, the more noise.
At some stage the clutch cover is not able to hold the noise inside the engine and you will hear it on the outside like an open dry clutch :mrgreen:
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda CBR 1000 RR SC57
Yamaha R1 RN04

BigGuy
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Re: Lucas Clutch friction plates

#8 Post by BigGuy » Thu Mar 30, 2017 7:59 am

OK, that makes sense. Thanks guys.
Shake "N" Bake!

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