Modern Vespa

Hey, I'm skeptical too and have said so as this has progressed, but I'm trying to be open minded given so many ppl have had good luck. No way I'd say 'no way' on a 3 plate solution, at least not yet w/ what Ginch is telling us. Like I said, I'm with you mostly and I'm not just speculating from my armchair: I know you have lots of experience and trying this should be a cake walk for you. How about I send you 3 corks free and you can help find out what's up and perhaps either confirm your initial opinions or learn something new?

Reading PMF's link, I now see how over time you might have a little more pressure closer in the the center because there's more wear where more work is being done further out. But that won't increase the clutch load capacity, rather seems it would decrease.

http://www.tech.plymouth.ac.uk/sme/desnotes/desclut.htm

I ran some numbers in the torque calculator provided there, but had to arbitrarily set the pressure loads at something in the range given, with the Vespa corks having 2/3 the pressure to reflect the proportionally greater area assuming same springs are used. Here are the results:

I think you're double dipping. The outer and inner radius take care of the surface area. So assuming same spring force, you should put in the same spring force.

Not that it really matters with this demo comparison, but there's 5 friction surfaces.

Same total force, but I believe the pressure per square mm or inch or whatever would be roughly 1/3 less for the Vespa corks(the reciprocal of the area ratio, with the CR having about 1/3 less area) and the calculator asks for pressure in N per sq mm, so I entered numbers that would anticipate using the same springs in both cases. All hypothetical, theoretical and armchair suppositions, but the calculator seems unbiased.

I should repeat what Ginch wisely posted earlier, this is no magic bullet so don't expect miracles. You may even get bored with your clutch if you do this.

Actually my rational was the following:

I wanted a Cosa style with longer primary (and interchangeable)

I wanted a smooth clutch as it was for my wife who has tiny hands

And why the extra on the CR corks? Because in the jolly ol' US it is easier to buy replacement CR corks than vespa ones.

It fit in the budget, i went for it.

I have ABSOLUTELY no slippage, they are amazingly smooth and grip ant every flick of the throttle. (I have an estimated 25+hp engine)

It runs great, woth the money if you go for Cosa style.

Heres seems a good spot to get the corks and they seem legit - I will have them soon an can report on quality. I have been looking and there's a wide variety available from kevlar to carbon fiber!!!

these "look " close to OEM ones...

http://www.ebay.com/itm/290862420810?_trksid=p2057872.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT

can anyone that has the CR plates in hand measure the thickness?

would be interested in the cork thickness with friction material and without, as well as the thickness of the steel plates.

The corks are about 3mm w/ lining and about 1.9mm in the slots between cork pads. CR steels are 1.6mm while Cosa steels are about 1.9mm and 7 spring steels about 1.5mm - these Vespa steels are used.


What's interesting is that the Vespa steels are both about 108mm OD(2mm smaller than the corks) while the dimpled CR steels are a full 110mm OD and still fit nicely inside the Cosa basket but are too tight for the 7 spring basket. Even more interesting is that Falcon ordered replacement Cosa steels from Mercato and surprise, they too now come dimpled in the same pattern as the Honda pieces.


CR steel diameter dimensions

Hey T... I hope you're doing well... call me and I'll give you my info on the CR80 Plate clutch... I've been running one for years (ever since the 1st came out) and it's a good upgrade....

You can spend big $ on one of the clutches made specifically for the CR80 plates (Like the LTH).. Or NOW.. everyone has jumped on the band wagon and started making CosaII clutches that accept CR80 plates ie: BGM...

OR..... you can take any CosaII clutch and (as you've seen in this thread (you may have verywell posted it)... you can adapts the CR80 friction plates to fit your clutch..

I took the LTH (w/ Honda plates) out of my Super (just because I'm anal)... and after 2+ years of HARD riding... they were still like new.. Never slip and last "forever"

Either buy one.. OR.. w/ a little Dremel work to the tabs of the CR80 plates.. you can have years of "slip-free" worry-free clutch operation..

Having said that..... I've had several other "high end" CosaII clutches (MMW v.2) & (S&S CosaII Evo).. which, when set up correctly (correct spacer washer, wavy washer, "Stover Nut" etc..) that have never failed me...

So having said all of that... my advice (if you have ANY kind of "SERIOUS" power coming out of your engine (as in big power...) I'd get a CosaII clutch and some CR80 plates... and you'll have a lot of slip-free miles to enjoy!

my 2C

Thank you Mr Vader, why am I not surprised that this is old hat for you? We now have 16 Honda corks on hand & will be setting up to trim their tabs. I have 2 used Cosa clutches to build, but also 3 or 4 seven spring that would benefit and can replace original six spring clutches on old bikes w/ rebuilt, maybe hopped up motor much cheaper than say, a stock Cosa or other premium clutch. Have you ever done a seven spring version or know of somebody else's experience with one? So looks like everybody that's posted using a Cosa based version w/ 4 plates cannot make these slip, even w/ lots of power. But you're the only one so far w/ a 7 spring 3 plate setup. I know you've gone at your motor, but cannot remember any details. Would you mind filling us in on just what kind of motor power you are handling w/ only 3 plates? Motor specs, please.

Well, previously it was handling it with 3 stock plates in a stock clutch. But eventually (2 years ish) that spread and fell apart.
It's a Malossi Sport, opened a little and carefully matched to the cases. 60mm Mazz crank flowed by Freakmoped. 1600g flywheel. Vortex carb. SIP road, sometimes JL L/H knock off.

I may need to add a spacer in there however, I do sometimes get a little 'lurch' at takeoff, more noticeable with a pillion. Or possibly go to stiffer springs which I'm trying to avoid.

So I received these corks and they ARE NOT as pictured . I received ones that look like the first set i got ... I emailed the co. and they say they are a paper based cork plate that are more expensive and better than cork as a friction material. They offer to refund me if I want - but now I wonder if anyone knows about the "paper" cork plates. Are they OK -as good or better than what Honda did 30 years ago or should i send them back and get my refund ,,,,? Pic on top is what i received - pic on bottom is from website.

While doing some research on clutch plates I came across a pdf from a guy who spent some hours removing all the material from between the raised parts of the friction material, saying that it helped to remove oil quicker and made it work better (based on the theory that the plates should be oily but have as little oil as possible to work efficiently).
So unless you spent a fortune on them it's probably worth giving them a try.

Today I was drawing out the stock large frame clutch vs smallframe vs motorcycle and one thing that adds to the thickness (reducing the number of plates) is that the pressure to disengage the clutch comes from outside the bell, while on motorcycles clutches it's a shaft that runs from the other side of the engine. I tried thinking of a way to fix this and thought of a car clutch that uses a diaphragm spring, the fulcrum would allow the motion to reverse without having a basket that takes it fully to the other side of the stack of plates.

Ginch, I'm sold. All that on a 3 plate w/ no slipping? I'll just do it & move on, w/ a Cosa if I can for easy pull, but 7 spring is still easy enough for me. If I hit any problems you'll be first to know.

Falcon, I'm not sure the 'best' upmarket CR lining makes a lot of difference to us. If we can make a clutch that handles 30 hp reliably w/o wearing out and you can make 25, why chase 40 hp? At least we gotta walk before we run. Just sayin'.....

Here's an used original Honda from a Honda motor on the right, the Brit one lower left(which I linked source) which appears same as Honda and your spare aftermarket one from the first posts top of page. The ones you just got now don't look as good as these, and yours here looks like it's NOT cork, but probably something that's somehow better. Notice that it has considerably less contact area, so proportionately higher pressure per sq mm.

The original Honda has metallic particles embedded, but I can't say if original feature for better clutching or courtesy of exploding motor it was in. There's very little wear compared to Brit corks which have identical cork pattern & dimensions leading me to think same factory and exploding motor on the used corks.

Regardless, as G said, it's just a clutch and if it works it's time to move on and of course, report our results when we actually have them too. Measure one of those you've been thrashing against the spare & see how much is gone.

Well unless they will pay for shipping back it was 15$ to my door so maybe I'll use them for a stock build and or do more research and see whats up.
Tomorrow gonna open that clutch and have a look see.

Edit - took my clutch apart at Voodoos today and the plates after about 500 mi show no real wear - we measured them against the new unused we had left and it was like less than a 10th mm difference , no slippage at all . so maybe these are ok - I just never saw this type of friction material and was put off at first. I'll do a few 1000 miles now before winter and we'll see what happens.

I took it apart as well as I thought i was hearing some slight scraping - Sure enough the ends of the corks are slightly larger then OEM too so a grinding of the inner of the clutch cover was in order.
It was barely touching and in scoot when i turned it i didn't hear anything after install. So a word to the wise just grind your cover or possibly could dress the ends of the tabs on the corks - we are talking a very small amount here.

The Falcon was telling me about this at Amerivespa. And, it just so happens, I fubar'd my clutch on the ride home from our rally this weekend. I was able to limp it the last 1/2 mile home. I'm guessing I flared out my basket yet again.


SO, I have a banded 7-spring basket, and all of the other tidbits. I want to give the CR800 plates a shot.

Therefore, come get three but you'll need to trim a bit off the tabs to fit your basket. I have typically shuffled this project aside to the middle burner. I have some of the gear now to setup for tab trimming fast and accurately, but have not taken time to make an adequate & quick indexing holding fixture.

Easy enough to trim down a few by gauging to your basket & sneaking up on it Falcon's way. I will be running 4 of these in a Cosa clutch in the cutdown and will probably do the same so I can try these too and fiddle w/ further tooling come winter if I like 'em as much as ppl who already have 'em.

Who else local or at least USA want's to try fitting a set to their 7 spring clutch? Nearly everybody is using them in Cosa or aftermarket clutches & I want to know how well they resurrect old 7 spring clutches for upgrading sub 200 motors. I can mail maybe 3 more sets to the bold & adventurous...

Once I get all of the bits together, we should make a night of it. I'll haul myself and my clutch over.

So my clutch is holding up great on two different kitted scoots - one is a standard Cosa the other is a BGM one - in both cases - even with the cheaper "looking" CR 80 corks it doesnt slip a bit.
I am soon going to open one of the engines so I will see what the wear is after a few 1000 miles. Probably around 500 or more on it now.

I am going to try it out on a 7-spring clutch. I have an upgear kit with straight-cut gears so, I can not easily switch to a COSA. BUT, really want to see if this trick will keep me from having to pull out my clutch so often

I have a question regarding using these plates in a 7 spring p200 clutch... I'm not sure if it's been gone over and I missed it or not.

The top plate in a 7 spring clutch is the one with cork only on one side, has T tabs on it, I'm assuming to keep the basket from spreading on a non banded clutch.

When using these Honda plates what are you using as the top plate?

I'm setting out to do exactly that, however using a banded basket. IStill waiting on parts but, if you don't find an answer before then, I will try to update with pics how that top plate works. V oodoo is going to walk me through the whole thing.

May be worth having a top plate made in steel that supports the basket and has the friction material on it. This could be thinner than the combination of the CR plate and the supporting ring that rests on top of it.

But, I would think, you could likely grind the friction material off of one side, or even just leave it there if it does not interfere with the clip. Use it just like you would a top plate. They are a bit thicker than stock plates. Grind the ears to fit. Should be able to support the rest of the basket. But, as I have said, I haven't actually had hands on them

You take one of the plates and remove the friction material from one side . It's a bit of a PITA - but all I could think of and works brilliant. I used something akin to a small putty knife with a good edge and finished it w sandpaper.

Shaving one side works for a Cosa clutch. We haven't done a 7 spring yet. I also like the T tabs on the stock top plate and believe you are correct that they would help keep the top of the basket from spreading so I'm thinking to try just using the stock top plate if we can.

Incidentally, I did try using the 7 spring top plate on a Cosa basket for the same reason, but the Cosa basket is just a wee bit bigger & it won't fit.

I will be running a banded clutch so, I may not worry about the T-tabs and go for broke.

I think the video on the last page shows it being taken off one side of the plate... if it takes you more than 10 minutes you're doing it wrong... put down the kitchen knife and use your angle grinder.

I was thinking along the lines of a wire-wheel but, I see where you are going.

I received my new basket, brass tidbits and what-nots. I need to pull the old clutch out and truck on down to see V oodoo

standing by...

I pulled the stock 21T clutch from my Cosa II motor that was gathering dust and found it to be in excellent condition. I just ground & filed the tabs on one side to fit after marking them w/ a scratch & gaging w/ the basket much like Falcon did. I'm using the original Cosa top plate w/ lining one side only. Current plan is to try it in a Sprint motor we hope to build as a spare for Kevelis.

I have a super strong basket in my 221. Been using sip plates as they are thicker but they still bend up and start slipping at around 3000 miles.

I have been looking for the CR ones pre modified since the last time but my winter overhaul is coming up and you've all convinced me to buy a set and grind them myself.

They arrived yesterday. Look just perfect and I think I'll manage. The most surprising thing is how light they are. Definitely a few free rpm there, cheers

You are going to be really happy!!!

from the ceramic disk thread: Well I discovered why my clutch started slipping so bad, take a look at the original cork on the left! The CR80 corks took about 2 hours total to pull the old clutch, grind & fit the new corks and reassemble everything. I just laid the bike on its side, had all the tools ready and did NOT run into any difficulties or surprises - at least until & got the clutch apart. Grinding & fitting the CR80 tabs to the basket took maybe 5 to 10 minutes per disk.

Be sure to file the sides of the slots in the clutch bell smooth and remove any burrs and sharp edges on the inside corners. After grinding the tabs file the inside corners clean so they don't hang up in the slots.

I used 2 CR80 corks and the original T slotted top cork which was still in OK condition because I like that the T slots help keep the clutch bell from spreading. The results were satisfyingly boring - no additional power, no sexy sounds or even looks, BUT no more slipping and real nice linear engagement without a hint of grabbing.

PS I have a set of brand new Vespa 7 spring corks for sale cheap! They've even been oil soaked for you already.


getting ready

marking all the tabs

you can see the marks I scribed, about 1 1/2 mm to come off

cutoff wheel in angle grinder lashed to the vise

So what happened to the tabs that were on the trashed old cork?
I hope mostly wound up here. I like to put magnets on both drain AND filler plugs just in case.

if its cheaper i might try this method once my clutch start to tear off

I think you will like it, Ebeth. Meanwhile, a small update. I was worried about more clutch bits inside the motor but I'm to lazy to split the motor to deal with it properly. So I decided to flush gasoline thru the gearbox to see if I could recover some more scrap metal.

With the bike propped up leaning away from the motor, I poured in 1/2 a liter of gas, put in fill plug, stood it up and ran the motor gently revving in neutral for a minute or so. The internal rinsing seemed to work and by the 5th rinse cycle the magnet was coming out w/ just fine fuzz and I was out of unmixed gas.

I will now add gear oil per spec and ride it around for a few days, then change oil and see how the new old oil looks. As you can imagine, the old old oil was quite sparkly.


first rinse cycle w/ gas

second rinse cycle, third was half of this or less and fourth time drain plug was like the filler plug here

Dang Terry, that's a LOT of swarf.

Are you cleaning the corks before you install them?