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#Post#: 2358--------------------------------------------------
Rocker Arm Shim Washers and Springs
By: patentgeek Date: June 7, 2018, 8:47 pm
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Paul Friday says: "Both rockers have their end float taken-up
by a spring with a shim washer on each side. Due to the thrust
of the pushrods being in different directions, each rocker has
the spring on a different end. The inlet rocker has the spring
at the valve end, the exhaust rocker has it at the pushrod end."
The rocker arm springs on both my intake and exhaust rocker arms
are on the valve end. When I dis-assembled the exhaust rocker
arm to correct this, I discovered that the shim washers that go
on either side of the spring don't fit the diameter of the
rocker arm spindle on the pushrod end. So it appears they can't
be assembled per Paul Friday's instructions.
I can't find any clarifying information in the English language
Factory Riders Handbook or the Italian language Factory
Maintenance Manual. The Italian language Factory Parts Manual
only shows one orientation for the rocker springs, on the
pushrod end of the rocker arm. However, I note the intake
rocker arm shown in the Factory Parts Manual is shown reversed
from its proper position, which doesn't give me a lot of
confidence in that diagram as a reference.
Thoughts?
#Post#: 2359--------------------------------------------------
Re: Rocker Arm Shim Washers and Springs
By: patentgeek Date: June 8, 2018, 12:37 am
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I took another look at this with my spare rocker box, which is
from a very early NF, and discovered that the washers can be
configured to accommodate Paul Friday's recommended shim washer
/ spring configuration in my first post. Although I questions
the benefits of doing so (more on that below).
There are (2) types of shim washers on the rocker arms: one type
is thicker with a smaller inner diameter, the other type is
thinner with a larger inner diameter. Each rocker arm has (2)
of the thinner/larger-ID shim washers and (1) of the
thicker/smaller-ID shim washers.
The thicker/smaller-ID shim washer only fits on the pushrod end
of the rocker arm spindle closest to the oil feed.
On the intake rocker arm, the (2) thinner/larger-ID shim washer
are both used on the valve end of the rocker arm to sandwich the
spring. The thicker/smaller-ID shim washer fits on the pushrod
end of the rocker arm, and acts as a thrust bearing (per Paul
Friday).
On the exhaust rocker arm, (1) thinner/larger-ID shim washer and
(1) thicker/smaller-ID shim washer are used on the pushrod end
of the rocker arm to sandwich the spring. The second
thinner/larger ID shim washer is used on the valve end of the
rocker arm as a thrust bearing (per Paul Friday).
intake rocker arm assembly
thicker/smaller-ID washer ||| ROCKER ARM ||| thinner/larger-ID
washer ||| spring ||| thinner/larger-ID washer
exhaust rocker arm assembly
thicker/smaller-ID washer ||| spring ||| thinner/larger-ID
washer ||| ROCKER ARM ||| thinner/larger-ID washer
On my spare rocker box assembly, I discovered that the exhaust
rocker arm interferes with the rocker box aluminum casting if it
is assembled with the spring and washers on the valve side. But
per the above, this rocker box is from a very early bike, and
the rocker box on my later engine (in my bikes) does not have
the same interference issue.
So what does all of this mean?
It seems odd to me that a thicker shim washer is being used as
thrust bearing on the intake rocker, but that a thinner shim
washer is being used as a thrust bearing on the exhaust rocker.
#Post#: 2363--------------------------------------------------
Re: Rocker Arm Shim Washers and Springs
By: banquo Date: June 8, 2018, 3:48 am
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They are supposed to go at opposite ends as per Paul's
instructions, and the washers are different.
Bear with me; I have some pix from when I had mine in bits.
#Post#: 2364--------------------------------------------------
Re: Rocker Arm Shim Washers and Springs
By: banquo Date: June 8, 2018, 4:12 am
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Hmmm. As always, you don't have the pic you really wish you had
taken.
Here are the parts as removed:
HTML https://farm5.staticflickr.com/4761/39459892975_de45cc7192_z.jpg
HTML https://flic.kr/p/237Wgqkrocker
parts
HTML https://flic.kr/p/237Wgqk
by bancquo
HTML https://www.flickr.com/photos/17279292@N03/,
on Flickr
Not very helpful, but you can see the springs sandwiched between
two thrust washers. The blued washer is the thrust washer from
the other end.
So, on the inlet rocker, starting from the fat end, we have
thrust, spring, thrust, rocker, blued washer, and the exhaust is
the other way around.
If yours was assembled with both springs at the same end, I
imagine that the rockers wouldn't align properly with the valve
stems.
I don't seem to have a pic of the exhaust, but here's the
assembly of the inlet, where you can see that I've identified
the rocker, and where the spring goes (and proof that the new
oil feed works, after kicking it over a few times after rebuild
;) ).
HTML https://farm1.staticflickr.com/790/40131332335_70d564dba1_z.jpg
HTML https://flic.kr/p/249gyX2oilfeed
proof
HTML https://flic.kr/p/249gyX2
by bancquo
HTML https://www.flickr.com/photos/17279292@N03/,
on Flickr
Hope that's some help
#Post#: 2367--------------------------------------------------
Re: Rocker Arm Shim Washers and Springs
By: patentgeek Date: June 8, 2018, 2:21 pm
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I took a picture of my spare rocker box assembly assembled per
Paul Friday's recommendation:
HTML https://1drv.ms/u/s!AuFSdkt2JFpfhqUJCoWRkZz9ARA-pQ
What I find odd is: (1) none of the factory documentation
indicates that the shim-washer/spring sandwich goes on opposite
ends of the intake and exhaust rocker assembly, which seems
pretty important for proper rocker/valve-stem alignment; and (2)
that the thicker shim-washer is used as a thrust bearing on the
intake rocker, but a thinner shim-washer is used as a thrust
bearing on the exhaust rocker.
The thicker shim-washer can't be used as a thrust bearing on the
exhaust rocker because it has a smaller ID and won't fit on the
"fat" section of the rocker arm spindle.
Paul Friday's recommendation makes sense on the intake rocker,
but it seems like a different combination of shim-washers would
have been designed for the exhaust rocker so the thrust bearing
shim-washer thickness was thicker.
#Post#: 2370--------------------------------------------------
Re: Rocker Arm Shim Washers and Springs
By: patentgeek Date: June 8, 2018, 2:45 pm
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Banquo, I found a pic of your rocker box here:
HTML http://photobucket.com/gallery/user/bancquo/media/cGF0aDpDbGFzc2ljIEJpa2VzL0ZhbGNvbmUgRm9ydW0gU3R1ZmYvUGF1bCBGcmlkYXkgdXBsb2Fkcy9PdXRzaWRlX3pwczVhZGVmZjY5LmpwZw==/?ref=
Note the pic is upside-down with the exhaust rocker on the top
and the intake rocker on the bottom.
Your pic shows a thicker shim-washer being used as a
thrust-bearing on the fat (valve) end of the exhaust rocker
spindle. However, the inner diameter of my thicker shim-washers
is too small to fit on the fat end of the spindle.
#Post#: 2371--------------------------------------------------
Re: Rocker Arm Shim Washers and Springs
By: banquo Date: June 8, 2018, 3:47 pm
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Sounds like you have the wrong washers then. It's unfortunate
this came up after I'd put mine back together, as measurements
aren't possible now, but they are definitely sided as Paul said,
as mine was 'new' when delivered, and came like that. Whether or
not it's important is another matter.
#Post#: 2374--------------------------------------------------
Re: Rocker Arm Shim Washers and Springs
By: patentgeek Date: June 8, 2018, 3:55 pm
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Yeah, maybe one of my thick shim-washers should have a larger
ID.
It shouldn't take long to reconfigure my exhaust rocker per the
Paul Friday recommendation. I remain surprised that this isn't
documented in any of the Moto Guzzi manuals.
#Post#: 2375--------------------------------------------------
Re: Rocker Arm Shim Washers and Springs
By: patentgeek Date: June 8, 2018, 4:32 pm
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More confusion in the factory parts manual. . . .
The shim-washers (#31) on either side of the spring (#32) are
described as "anello di spessore" which translates to "thick
ring". But these are actually the thin shim-washers.
The shim-washer (#33) that sits opposite the shim-washer/spring
sandwich is described as "anello appoggio bilancere" which
translates to "balancing support ring".
There are only two types of shim-washers identified in the
factory parts manual. But per the discussion above, since the
intake rocker shim-washer configuration is the reverse of the
exhaust rocker shim-washer configuration, the shim-washers
acting as thrust bearings (i.e., balancing support rings) should
have different diameters since one should sit on the fat end of
the exhaust spindle and the other should fit on the skinny end
of the intake spindle. Which would require three types of
shim-washers.
Weird.
#Post#: 2377--------------------------------------------------
Re: Rocker Arm Shim Washers and Springs
By: banquo Date: June 9, 2018, 2:36 am
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It's really frustrating that this didn't come up when I had all
the parts to hand.
I don't recall them being different diameters though.
Kater or Huub will know, and maybe you'll get a response from
the FB post.
Advrider gets more traffic than here, and almost certainly will
get a positive response
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