Driveshaft/Gearbox

[pete roper]

23 minutes ago, footgoose said:

Yes it can docc. What I wonder is if RAM were making a version of the current (steel) lightened clutch assembly before Guzzi got the idea to have them produce the Aluminum flywheel single plate assembly for their 'specials.' So,... was it a Guzzi design in the beginning for the RM? .. and subsequently passed down to Scura and Tenni? Or a RAM design at the bequest of MG?  or ...once it proved weak and discontinued through the line, did RAM decide to make it better?

The lightened flywheel/clutch assembly introduced as oem in the V11 range was a good idea, but a failure.

The tried and true reliable dual plate kit is the way to go for replacement ... says the Guzzisti in me. The smart me says avoid the 'presumed experiment' oem alm kit altogether. It's not worth the worry. The adventure me -thankfully- went with the later RAM single. And I think it fits closer to intended oem spec for the purest in me. It's too bad this assembly was not used throughout the spine line.

I can tell you that the RAM single plate assembly has been around since the 1980's. It was a fairly popular mod back in the day. It had a couple of problems. One was the fact that people used to buy the 'Race' version which had a sintered bronze friction material. Now this was all well and good in that it had good take-up and feel but it also wore very fast! Like in a road bike being ridden in a 'Sportsman's-like' manner you'd get 2,000 miles out of a plate if you were lucky! You cold also get an organic plate but it wasn't called 'Race' so knobs didn't buy it but it lasted ages and was a happy thing. I honestly can't remember whether those early flywheels were steel or aluminium? They were light though.

I have no idea what the story was with the Scura etc. flywheels and clutch but they were built by RAM. My WAG is that Guzzi went to them and said they wanted some clutches but specified their own materials and thought they were being very clever by specifying aluminium for the flywheel and it turned out to be another of those 'Big wooly ears' bits of engineering that the in-house engineers used to throw out from time to time. Anywhichway it was a shitfight and remains so to this day!

Lightening the flywheel used to be one of the 'Holy Grails' back in the Tonti days. Anyone who was building a hot-rod wanted the lightest set up they could find. I did it myself! In the end my 891 short stroke thing I built used the twin plater but with an alloy flywheel and very seriously lightened ring gear. It probably want quite as light as a RAM unit but it was extremely durable.

After that project though I learnt to appreciate the wonders of a heavier flywheel in most road going situations. In fact in my old SP which had a mildly warmed over 950 Mid-valve motor in it I actually used an Eldorado flywheel, the heaviest one Guzzi ever made! It was a hoot to ride! Even my current *Fast* 8V Griso has a Cali 14 clutch in it that is heavier than the earlier 1200 clutch assemblies. It's a better bike for it.

If I had a V11 with a single plater I'd just go twin plate with an alloy flywheel again. It worked well.

[docc]

My impression has always been that the original V11 steel flywheel (twin plate clutch) was an OEM "lightened" version.

Is the standard V11 flywheel actually lighter than previous 5 speeder flywheels?

[fotoguzzi]

If it’s the same as a Centauro then yes it’s lighter than the Tonti FW.

 

[pete roper]

Just now, docc said:

My impression has always been that the original V11 steel flywheel (twin plate clutch) was an OEM "lightened" version.

Is the standard V11 flywheel actually lighter than previous 5 speeder flywheels?

Oh yes. A shittonne lighter. The flywheels and on later models the ring gears have got a lot lighter over the years. The early loops had a flywheel that actually had its own gravitational pull and light would bend going past it! It was vast, as was the ring gear. With the advent of the V7 Sport and 850T it was lightened considerably but it was still huge. That flywheel was what was used in all the T series bikes, the SP, Mille GT, Californias etc. The ring gear was also thinner. Then came the LeMans series and this was lighter again but was still a 'Full Circle' flywheel and used the same ring gear as the 'T' models. After this, with the advent of camshaft triggered ignition there was no longer the need for a full circle flywheel with timing marks so the Daytona and then the Sport 'C' and Centauro got the relieved steel flywheel, (As shown above while I was writing this.). The ring gear was also lightened once again and this assembly remained pretty much identical throughout the entire V11 series and the 2 valve per cylinder CARC bikes that superseded them. The one real oddball was the Sport 'C'. This has its own *Special* flywheel with triggering knobs on its perimeter as they use a weird twin trigger system for their ignition.

[cash1000]

At last got Clutch & Flywheel out. Clutch took some gentle persuading with a pry bay.

No visible damage to either but will get flywheel crack tested 

 

[cash1000]

24 minutes ago, cash1000 said:

At last got Clutch & Flywheel out. Clutch took some gentle persuading with a pry bay.

No visible damage to either but will get flywheel crack tested 

 

Stuffed up photos

Here is one 2 others in my gallery

 

[fotoguzzi]

So if nothing wrong is seen the problem must be inside the transmission and not the clutch?

[gstallons]

On 1/11/2023 at 9:52 PM, docc said:

Just pondering this "low inertia" clutch plate looks to have, maybe 1/3 the surface area of a single OEM clutch plate.

And that my twin plate has two; making six times the mass/area (roughly) of this "low inertia" plate.

Might they only last 1/6 as long?

 

This "paddle" type clutch disc is designed to allow air in, around, through the friction area for cooling purposes . The same as drilled,grooved rotors on brake systems . 

 Large trucks (when they had M.T.s ) would use these clutch discs,

[Pressureangle]

1 hour ago, gstallons said:

This "paddle" type clutch disc is designed to allow air in, around, through the friction area for cooling purposes . The same as drilled,grooved rotors on brake systems . 

 Large trucks (when they had M.T.s ) would use these clutch discs,

To add, a full-ring disc (of any sort, in any device) is more prone to resonant vibration and potential failure (flywheels?) than if it's segmented. As far as the square inches of friction material, it's irrelevant except for the wear factor. The spring pressure and coefficient of friction determines the holding power, although less inches means higher coefficient which means grabbier friction zone. Particularly with modern material science, what you see is more likely to be mandated by drivability and cost than by performance and durability. 

I restored a '51 Pirsch fire pump, which resided on a 'truck'. (wagon attached to and powered by the pump motor). 
The clutch was dual disc, 3 pads per disc of some metallic sintered material with no cushion in the discs and a pressure plate sprung so hard I thought I'd screwed up something during assembly. 

Turns out it was my ignorance of application- in '51 they threw the water hose in a pond or ditch and pulled the pump WOT on the old 500 cubic inch Waukesha. If the source ran dry and the pump sucked air, when you threw the hose into a new spot and the water hit the pump it would instantly slip and murder the clutch on a normal over-the-road truck clutch. Drivability was not an option- the pedal was hard like rock and the action was like a light switch. But it didn't die on impact while doing it's job.

[cash1000]

8 hours ago, fotoguzzi said:

So if nothing wrong is seen the problem must be inside the transmission and not the clutch?

The shattered bearing in gearbox told us problem was defintley there.

With gearbox out it made sense to check the clutch and flywheel for any wear

[cash1000]

3 minutes ago, cash1000 said:

The shattered bearing in gearbox told us problem was defintley there.

With gearbox out it made sense to check the clutch and flywheel for any wear

The $64m question is if flywheel is ok do I replace it anyway

[fotoguzzi]

To paraphrase Dirty Harry, do you feel lucky kid?

[fotoguzzi]

Well the replacement flywheel only is $580.US and not in stock..

https://www.mgcycle.com/index.php?main_page=product_info&cPath=193&products_id=4409

makes my complete kit offered for $350US sound like a real steal. I must be out of my mind to sell for that🙃

This is used out of a Centauro but will fit the six speed too. NOT ALUMINUM but light. Weight, about 9 pounds

. Splines look excellent. I’ll even order new springs for you.

https://www.mgcycle.com/index.php?main_page=product_info&cPath=193&products_id=4986

I’m not trying to pressure you cause I’m happy to keep on my shelf for now, just sayin..pressure plate/ring gear, friction and intermediate plates included. I think Pete recommends new friction plates. I could get them from MGcycle and put in the same package I bet..

shipping about $75US if they fit in a flat rate box.

 

 

[pete roper]

Brad’s offer is very good and the way I’d go. In fact I did with Chuck’s old Scura when I bought it. 
 

I’d get the pressure plate and ring gear ground and fit new friction plates and intermediate and you’ll never have to look at it again. 
 

Brad? Do you have the thrust cup for it as well?

[fotoguzzi]

I just looked, it was not in the package with the kit. BUT I have another clutch from an EV big twin minus the flywheel and there is a thrust cup with that. It fits the Centauro pressure plate so I would include that. So yes I have one that will work.