LOOP FRAME INTERMEDIATE PLATE WARP

[lazlokovacs]

Grrrrrrr.

Got the dreaded clutch drag on my loop 4-speed.

Creeping at the lights, lurching when trying to stop.

I have duly;

removed, inspected, obsessively measured and re-measured clutch cable to ensure that no stretching is taking place.

made a tool for measuring the recess distance of the outer throw out bearing. It is 4mm recessed into the transmission body. This possibly rises when the engine is hot. Hard to be sure.

removed, inspected, assessed and replaced the throw out bearing (thrust bearing.) It was slightly worn.

Symptoms are that the bike starts to drag after a few minutes of riding. If I switch bike off and allow it to cool it beahaves again for around the same length of time.

The drag seems to at its worst when pulling the clutch lever in to stop.


Here's the history.

I never ever ever ever ever sit with the clutch lever in at red lights. I've been good to this clutch, but living in a major city of 10million it does get a fair bit of intentional slippage.

Clutch was completely replaced 4 years ago at Corsa Italiana in London by a highly experienced guzi mechanic. (now closed unfortunately, or I'd be asking them about this....)

Here's some theory

Apparently the intermediate plate can warp under high heat. I'm not sure if this is relevant, but my problem has started during one of the coldest winters we've had for many years.


Here's my question.

shall I go in?

Any tests to confirm that it is indeed a warped plate before I tear down the bike?

How can I be sure that I won't be having the same problem in another 10,000 miles time?

Which plates to order? Avoid the surflex?

Where can I be sure of getting quality plates that won't dish.


Thanks for your time everyone 
 

[Antietam Classic Cycle]

The outer body of the throw-out bearing should not be recessed 4 mm into the rear cover plate. Optimum is just about flush. Something is amiss if it's that recessed.

If it has Sureflex friction plates, then they have likely notched the hub and that is causing most if not all of the issues. The symptoms you list are almost identical to those my "Barney" had prior to replacing the Sureflex plates with SD-TEC plates.

In any case, a tear down is in your future.
 

[radguzzi]

I would like to add an FYI as well regarding the springs.  I recently encountered a free measurement on Aftermarket clutch springs that drove me insane, I could not adjust the issue out.  Total clutch component replacement, either a slipping clutch or creep in gear, two additional tear downs to figure it out in fact.  I got good at down and back with an Eldo... :( 

Anyway, watch the length, replace if too short and grind to EXACT length if too long.  Best bet is buy OEM springs.  I did not measure the Aftermarket Springs prior to the first installation so, please do that first.

Best,
Rob

[bigbikerrick]

What Charlie describes with his "barney" is exactly what happened to my eldo. replaceing the sureflex clutch with sd tec, and new 4 mm clutch hub, took care of the problem. My 2 mm clutch hub was pretty badly notched.
I also installed a rear cush drive/ brake assembly from an 850T, and driled the cush rubbers.
After all this, my eldo has a nice , progressive,clutch action.
before, it was dragging after heating up like you describe.
Rick.

[pete roper]

Notched hub and/or flywheel splines. AFAIK you can't get a 4mm hub for the 4 speeds but Charlie'd know.

[Antietam Classic Cycle]

Notched hub and/or flywheel splines. AFAIK you can't get a 4mm hub for the 4 speeds but Charlie'd know.

They are available or were - MG Cycle was selling them, but IIRC they were experiencing difficulties with the supplier and stopped. I still have one in stock. There's a company in Germany that sells them, though I can't share a link because that bookmark was lost when I replaced my computer a few months ago. 

[lazlokovacs]

Thanks guys

forgot to mention, I changed the flywheel with the clutch 4 years ago.....

Really not too pleased to have to be going in again so soon

hey ho could be worse

could tighten things up in the gearbox while I'm at it

looks like some thisoldtractor reading beckons!

[lazlokovacs]

So I've done a bit of research...

Not going to tear it down until I have the right parts to replace it with

Either,

I should be looking at finding a 4mm hub from Germany (charlie -tried Stein dinse in Germany but they didn't have them...)  and corresponding SD or Newfren plates...

Or old style Newfren plates from Italy and keep the shallow hub?

Have contacted both suppliers, will wait and see what they have for the 4 speed

also- 

anyone have any experience with notching the intermediate plate?

http://www.thisoldtractor.com/guzzitech.dk/pdf/clutch-intermediate-plate-heat-warp-the-cure.pdf

[kidneb]

Grrrrrrr.

How can I be sure that I won't be having the same problem in another 10,000 miles time?

Which plates to order? Avoid the surflex?

Take it apart and make things right.

Best you can do is to hunt down a deep spline hub and fit a pair of SD-tec plates + of course other parts that need replacing.

But with both the 4-and especially the 2mm hub,- avoid those horrible Surflex !


Moto Guzzi Pirner in Germany has the deep spline hub listed in their catalogue on page 25, but I don't know if they are available at the moment.

            http://www.moto-guzzi-pirner.de/en/index.html

   Good luck

[Antietam Classic Cycle]

Take it apart and make things right.

Best you can do is to hunt down a deep spline hub and fit a pair of SD-tec plates + of course other parts that need replacing.

But with both the 4-and especially the 2mm hub,- avoid those horrible Surflex !


Moto Guzzi Pirner in Germany has the deep spline hub listed in their catalogue on page 25, but I don't know if they are available at the moment.

            http://www.moto-guzzi-pirner.de/en/index.html

   Good luck

  That's the place I was trying to think of.

I've never seen the need to notch/slot the intermediate plate, but then I'm not pulling a heavy sidecar and/or trailer. I do prefer the "better quality" intermediate plate that MG Cycle sells over the cheaper one.
http://www.mgcycle.com/index.php?main_page=product_info&cPath=193&products_id=4789

[lazlokovacs]

thanks guys, just the info I needed, thanks

on a more positive note, I built a pretty great front end for my loop out of Cali Vintage and Breva parts this winter, so I now have my favourite ever guzzi in a format that handles as good as can be hoped and stops like a ducati sport tourer! Shame this clutch thing had to happen now, but hey I'll get in there and do it right and give the gearbox a shim at the same time...

Will post pics when its all back together, I managed to keep the fork shrouds and the original dash as part of the conversion which I was very pleased about...

Really really appreciate all the advice and wisdom

Cheers

Ps - charlie - I've had similar experiences to yours on other Guzzis with Surflex, really annoyed me, I can't believe that any company could get away with selling a product so unfit for purpose...

[kidneb]

Just for your information, Uwe Pirner at Moto Guzzi Pirner has been producing the deep spline hub for the 4spd gearbox for more than 20 years, and they are available at the moment, ready to order.

[lazlokovacs]

thanks kidneb

just got off the phone with Herr Pirner and I have a set of plates and a new hub on its way to me...

seems like a nice guy to do business with

[kidneb]

I can see he's selling the deep spline hub as part of a kit that includes Surflex friction plates,- you're not buying those are you ? 

[lazlokovacs]

NOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOO WAAAAAAAAAAAAAAAAAA AAAAAY

getting the kit but with NewFren plates!

(according to a friend in the know they are as good as or maybe better than the SD plates, obviously I'm not discounting the value of the venerable advice offered in this thread)

 

[Antietam Classic Cycle]

NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO WAAAAAAAAAAAAAAAAAA AAAAAY

getting the kit but with NewFren plates!

(according to a friend in the know they are as good as or maybe better than the SD plates, obviously I'm not discounting the value of the venerable advice offered in this thread)

 

If the Newfren are the type with the "spoked" centers, then I'd think twice.





It's not uncommon for the "spokes" to fracture. Usually takes 50k miles of hard use (pulling trailers and such), but I wouldn't risk it myself. The SD-TEC plates are bonded and riveted, with solid centers. A lot less chance of failure.

From another thread here:

[jacksonracingcomau]

If the Newfren are the type with the "spoked" centers, then I'd think twice.





It's not uncommon for the "spokes" to fracture. Usually takes 50k miles of hard use (pulling trailers and such), but I wouldn't risk it myself. The SD-TEC plates are bonded and riveted, with solid centers. A lot less chance of failure.

From another thread here:

Thats AP LOCKHEED not newfren
But I break neither, big miles, ride hard but not hard on clutches
Newfren feel is excellent, but possibly not for trailer queens or sidecars/trikes, outside intended use perhaps. Op not one them, he will not break newfren,
In fact have not seen pic of broken newfren only ap and oe rivetts from 70’s, I did pop some of them back in the day .
If you know of broken newfren tell story of load that broke it.