Clutch Basket Bearing Recommendations? 860GT

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ducadini
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Re: Clutch Basket Bearing Recommendations? 860GT

Post by ducadini » Sat Aug 19, 2017 10:33 pm

All springs in the clutch aren't the same, so when You pull the lever, the pressureplate tends to lift unevenly, and dragging on one side.
I added shims of 0.1under some of the springs to get a perfect lift.
But even then, I ALWAYS kicked the bike a few time with the clutchlever in, untill it was loose.
That first gear DOES already get a beating originally without that clutchsticking.

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herbg
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Re: Clutch Basket Bearing Recommendations? 860GT

Post by herbg » Sun Aug 20, 2017 2:32 pm

I gave Steve's suggestion a try this morning ... removed the nut from the actuating arm adjustment screw and turned it in as far as it can go. This left no threads exposed for the nut to go back on but wanted to see the effect.

Unfortunately, even with the "extra" leverage, and the clutch lever pulled in, 1st gear does not disengage. The the wheels are fully "locked" into 1st gear.

So, it looks like I have no choice but to take the case covers back off to see what's going on. I do remember having a very difficult time getting the new clutch springs tightened down due to their stiff nature. Might try putting the old springs back in to see if the problem improves.

Really want to avoid replacing the actuator arm and going through the rod and ball sequence again.

Jeesh ... this bike is a pain in the backside ... beautiful to look at, sounds incredible, but a son of a gun to actually get back on the road.
_________________________________
2013 Ducati 1200S Multistrada
1985 Ducati Mille S2
1978 Ducati 900 SS (Blue/Silver Borrani)
1972 Ducati 350 Desmo (Silver Shotgun)
1969 BMW R69S (Earles Fork)

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Old905Duc
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Re: Clutch Basket Bearing Recommendations? 860GT

Post by Old905Duc » Sun Aug 20, 2017 5:11 pm

Hmm, I also had problems with the Heavy clutch springs. For some reasons (I still do not yet understand) the clutch would bind when the Heavy springs were installed and fully tightened down. It almost seemed like a coil bound condition. Basically the clutch plate would not lift unless I backed off the spring screws. When fully tightened the clutch plate would not lift off of the clutch pack. After trying several experiments I reverted to the medium strength springs which were stronger than my originals but weaker than the Heavy springs. This solved the problem. You can find my observations of this problem earlier in this thread. Note that there are some dimensional differences in the various weight springs. I can't say if this is contributing to your problem, but thought that I would share my experience for what it is worth.

Best wishes!

Old905Duc

herbg
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Re: Clutch Basket Bearing Recommendations? 860GT

Post by herbg » Mon Aug 21, 2017 10:59 am

Yes, I'm also suspecting the springs. They were very difficult to torque down. I did think it was odd that they were longer than the originals. See the attached photo to see the difference.

Unless there's a reason not to do so, I will replace the heavy new springs with the original OEM springs to see if this helps.

Cheers,
Herb...
Attachments
Old vs New Springs.jpg
_________________________________
2013 Ducati 1200S Multistrada
1985 Ducati Mille S2
1978 Ducati 900 SS (Blue/Silver Borrani)
1972 Ducati 350 Desmo (Silver Shotgun)
1969 BMW R69S (Earles Fork)

ducadini
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Re: Clutch Basket Bearing Recommendations? 860GT

Post by ducadini » Mon Aug 21, 2017 4:29 pm

We used the stiffer-shorter springs (originally 450 Desmo stuff) without any problems in various engines, but with a lot of practice to get the lever pulled ;)

So sometimes we just fitted 2 or 3 and shimmed them to get even lift.
Coilbinding is VERY MUCH out of the question : with the longer lever the springs aren't pushed in as much as Original.
Fitting the springs was done with the Original screwdriver so when You say You had a hard time tightening them, something must've been wrong.
I know there were different clutches used over the years and not all combinations worked as they were supposed too.
Some of the plates have the teeth bended to one side, and it's rather Obvious they should be fitted so that they can be used.
You may have to move the pressureplate to a different position so the 6 holes line up AND the inner teeth of the plate fit in the inner clutchdrum.
The combination of rods and balls that actuates the clutch has to be fitted in the right order and filled with grease to prevent oil leaking through it.
It could be that the first clutch plate has it's teeth bended and has to be fitted with the teeth to the outside.
Seen it, done the mistakes but then fitted the (aparently) correct combination of parts and raced them.

ciao
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Old905Duc
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Re: Clutch Basket Bearing Recommendations? 860GT

Post by Old905Duc » Tue Aug 22, 2017 5:44 pm

Hello Ducadini,
You mention in your reply that you have used the "stiffer-shorter springs (originally 450 Desmo stuff) without any problems in various engines". It is interesting to note that both Herbg and myself found the Heavy(26Kg) springs to be Longer than the originals. By my measurements they were 2.1mm longer (not shorter) than the original springs (BTW they were also bigger in OD by about 0.45mm). Does this sound correct to you based on your experience?

The intermediate (22Kg) springs that finally worked for me were 2mm shorter than the originals but had thicker wire and the same overall OD as the original springs. Due to the thicker wire (2.2mm vs. 2.0mm) they do provide increased clamping force and higher lever effort.

Just sharing my observations.

Happy riding.

Old905Duc

ducadini
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Re: Clutch Basket Bearing Recommendations? 860GT

Post by ducadini » Wed Aug 23, 2017 12:24 am

Currently working on a new "shed" to work on the bikes so all my parts are secured in a storage facility. costing me a Ducati €€€.
Pretty sure that the box, containing original bevel clutch stuff, only holds 5 parts : the Original srews, washers, buckets (single-twin the same) and the two springs : long-soft (0400*16*550), short-hard (partslist in the storage . Easy to "measure" just by pressing them between the fingers. I don't remember any numbers.
Lately I've been working on my old beltdrives and , while not compairing them with the bevel parts, think those springs are a little longer.
So when compairing the partsnumbers, I found that the (early) belts use 5 different springs and I KNOW that the pull on my Alazzurra 350 is way more than the one on the 650 (but that could be 'cause the latter is a dry-hydraulic).
Don't have any dimensions of the springs, just partsnrs found at Steve's site.
But, since they are fairly cheap to make, it's Always possible that someone ordered a special batch .
Nevertheless, we only encountered clutch slippage when ABUSING (we were young and so were the bikes :-D ) and for racing went for the 450 springs so why not stick to the Original lighter setup ?

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herbg
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Re: Clutch Basket Bearing Recommendations? 860GT

Post by herbg » Wed Aug 23, 2017 9:18 am

Old905Duc:

Are the replacement springs from Steve similar in size to the 450Desmo springs ducadini refers to? How much do they differ from the original springs.

Since I have neither of these springs handy, I am inclined to go back to the original OEM springs as they seemed to be ok. I will find out if they are strong enough for the Surflex Modifica S1425 competition clutch.

When struggling to install the heavier, longer springs that came with the Surflex clutch, I did not experience flexing of the pressure plate since I'm using a HD unit purchased from Gowanloch. See the attached pic.

Cheers,
Herb...
Attachments
HD Pressure Plate installed.jpg
_________________________________
2013 Ducati 1200S Multistrada
1985 Ducati Mille S2
1978 Ducati 900 SS (Blue/Silver Borrani)
1972 Ducati 350 Desmo (Silver Shotgun)
1969 BMW R69S (Earles Fork)

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Old905Duc
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Re: Clutch Basket Bearing Recommendations? 860GT

Post by Old905Duc » Wed Aug 23, 2017 11:59 am

When I was upgrading my clutch I took several spring measurements to try and understand what was going on. I have created and attached a table of the measurements. Click on the table to view in larger size. BTW, that pressure plate looks quite strong!
Ducati 860 Spring Table.jpg
Both the original and the 22Kg (SM56) springs worked in my application (1975 860GT upgraded to the later clutch design but using original pressure plate and spring cups). The Heavy Duty 26Kg springs would cause the clutch to bind and the pressure plate would not lift. I purchased the 22Kg(SM56) and 26Kg(SM168) springs from from Steve. I am "guessing" that the 22Kg(SM56) springs are the same as the 450 Desmo springs mentioned by Ducadini, but maybe he can take some measurements to confirm(?).

BTW, here is a link to the clutch springs that Steve sells:
https://store.bevelheaven.com/Engine-Re ... gs-Bevels/

Old905Duc

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Craig in France
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Re: Clutch Basket Bearing Recommendations? 860GT

Post by Craig in France » Wed Aug 23, 2017 11:30 pm

Old905Duc wrote:
Wed Aug 23, 2017 11:59 am
When I was upgrading my clutch I took several spring measurements to try and understand what was going on. I have created and attached a table of the measurements. <snip>

Both the original and the 22Kg (SM56) springs worked in my application ... <snip>
For the record ;). Information taken from various factory workshop manuals and parts lists. Also presented as a table at the end of this post.

1. All 250s and 350s
Part #: 0400.16.550
Original spring length = 30.4mm. Load to reduce spring length to 20mm = 17kg. No minimum spring length given, but see below under the 860 entry.

2. 450
Part #: 0480.16.550
Original spring length = 27.5mm. Load to reduce spring length to 20mm = 21 kg. No minimum spring length given.

So both shorter and stronger ;).

3. 750s
Part #: 0400.16.550, i.e. same as 250s/350s.
The workshop manual is silent on the spring length (but see both above and the next entry).

4. 860GT/GTS, 750 & 900 SS up to 1979/80, Darmah to 1979
Part #: 0400.16.550, i.e. same as 250s/350s.
Original spring length = 30.4mm. Limit of wear = 28.9mm.

5. 900SS 1979/80, Darmah 1980, MHR
Part #: 0480.16.550, i.e. same as 450s.
Note: The consequent reduction in the free spring length is NOT reflected in the workshop manuals for either model.

6. 1982 MHR
New spring, part# 0799.16.550.
Haven't got the size details, and my brain is beginning to hurt ...

Clutch springs.jpg
HTH

Craig

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Re: Clutch Basket Bearing Recommendations? 860GT

Post by ducadini » Thu Aug 24, 2017 12:17 am

Thanx Craig, for searching the data.
To be honest : I was getting a headache getting the belt-springs into the equation. My bad :oops: :oops:

Nevertheless I stand by two rules :
Check that the clutchpressureplate is lifting EVENLY, and if so switch some springs from one side to another or add a shim.
ALWAYS give the bike a few kicks with the clutch in untill it's free.

The pain to get it going is over the moment it runs ;)

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Re: Clutch Basket Bearing Recommendations? 860GT

Post by Old905Duc » Thu Aug 24, 2017 8:10 pm

Eureka, I have found it!

Thanks to all that have contributed to this thread. I now FINALLY understand why the Heavy 0799.16.550 clutch spring did not work in my application or (likley) in Herbg's. Each of the replies to this thread added pieces that led me to my conclusion. Thanks all again! Here is my assessment.

The last reply by Craig identified that the Heavy spring 0799.16.550 was introduced on the MHR models. This prompted me to to dig deeper into the spare parts manuals on Steve's web site. Here is what I found ..........

Heavy clutch spring 0799.16.550 was introduced optionally or part way through the 900 MHR model run. Use of these springs also coincided with the use of longer clutch spring screws and a new clutch hub. This design change was then fully applied to the 900 S2 model. So, in order to use the Heavy springs you also need to use longer screws and revised new clutch hub part number 0799.16.590 instead of previous hub part number 0759.16.594.

So, in my case as well as Hebg, we have hub part number 0759.16.594 which is not compatible with the longer Heavy springs. Also the spring screws need to be longer. In my case I determined this empirically, but still had issues due to the wrong clutch hub. Without seeing the design changes in hub 0799.16.590 I would speculate that the spring post height was modified to accommodate the longer springs and longer screws.

The bottom line as I see it is that you cannot use Heavy springs 0799.16.550 unless you also have clutch hub 0799.16.590 and the corresponding longer screws.

So, my advice to Herbg is to either use his original springs, or the 22 Kg p/n 0480.16.550 (SM 56) that Steve sells to get a fresh set.

Wow ..... finally closure, I think.

Old905Duc
Last edited by Old905Duc on Fri Aug 25, 2017 2:01 pm, edited 1 time in total.

Vince
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Re: Clutch Basket Bearing Recommendations? 860GT

Post by Vince » Thu Aug 24, 2017 8:51 pm

I have had the same issue on another Maque, the parts bloke kept sending me the latest revised bit that was supposedly better. They kept breaking till I discovered what was happening, I asked for the earlier part and never broke another one. It only took a year and a dozen broken parts and stuffed ride days to work this out.

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Old905Duc
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Re: Clutch Basket Bearing Recommendations? 860GT

Post by Old905Duc » Thu Aug 24, 2017 9:21 pm

Yes, the devil is in the details ..........

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Craig in France
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Re: Clutch Basket Bearing Recommendations? 860GT

Post by Craig in France » Thu Aug 24, 2017 10:49 pm

Old905Duc wrote:
Thu Aug 24, 2017 8:10 pm
Eureka, I have found it!

Thanks to all that have contributed to this thread. I now FINALLY understand why the Heavy 0799.16.550 clutch spring did not work in my application or (likley) in Herbg's. <snip>
As so often, Ian Falloon tells the story. I quote (my underlining):

"After engine number 091267 there was a new clutch housing, with longer clutch springs and six longer (5x16mm instead of 5x10mm) Allen screws. The earlier springs and screws were not interchangeable with this housing"

This is 1981, btw.

Source: Falloon, 860 etc Bible, page 101.

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