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Tuber Front Isolator - Ask the audience...
https://ukbeg.com/forum/viewtopic.php?f=8&t=9932		 Page 1 of 4
Author:  pash [ 13 Feb 2011 21:58 ]
Post subject:  Tuber Front Isolator - Ask the audience...
Those of you that know me will know that I love my S1s. I have owned four of them over the past two years and have looked at the front isolator on three of them, plus I looked at the front isolator on a friend's M2. Each one has had the D-washer, in my view, fitted incorrectly, i.e. with the convex face facing upwards...

See, to me, I see the isolator as isolating the engine from the frame. Nothing should stop the movement of the bolt in any direction, apart from in a failure case...

So, I think they should be fitted like this:

Image

And not like this:

Image

for which the D-washer has left its mark...

Image

The parts book supports my view too:

Attachment:
iso late or.jpg
iso late or.jpg [ 6.75 KiB | Viewed 1684 times ]


The question is, why have HDB, and in one case a well known independant, fitted the washer the other way up? What am I missing???
Author:  neilc [ 13 Feb 2011 22:41 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
Not sure now you ask, mine was fitted as per your second picture however i am just starting to rebuild again after stripping for powdercoat over the winter so i am interested in results as am replacing all isolators and bearings whilst i'm at it.

Cheers

neil
Author:  Motorrad [ 13 Feb 2011 23:02 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
I agree with you, especially in light of the parts manual exploded view, showing the hollow in the washer clearly facing upward. However, mine is also installed with that recess down, and the convex side up - and I am almost positive this is the original, installed at the factory.

Installing it convex side down, it would seem the convex side would avoid the straight edge of the D washer from cutting into (damaging) the top of the isolator rubber. Yet no one seems to install it this way.
Author:  Motorrad [ 13 Feb 2011 23:12 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
Or, you could use the newest front isolator kit, which does not use the same D washer at all. :idea:
Author:  Nutah [ 13 Feb 2011 23:13 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
but IIRC the bolt is the wrong Dia. :headbang:
Author:  pash [ 13 Feb 2011 23:33 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
Plot thickens...

You look in the 2002 X1 (the perfect tuber) parts book and it shows the D-washer like in my first pic, yet you look in the SAFETY RECALL CODE 0810 - FRONT ISOLATOR MOUNT SYSTEM:

http://www.badweatherbikers.com/buell/m ... 263565.pdf

and it appears to be the other way up...

This guy likes to put his on like picture 2 aswell...

http://www.badweatherbikers.com/cgibin/ ... OST1773903

And the new one, IIRC has a "top hat" onto which the rubber is bonded...

http://www.badweatherbikers.com/buell/icons/link-up.gif

Further discussion:

viewtopic.php?f=7&t=5797
Author:  kevmean [ 13 Feb 2011 23:56 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
My X1 is as per picture 2 and is the original factory fitted mount ;)
Author:  Motorrad [ 14 Feb 2011 00:46 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
Ah, with that contradictory service bulletin diagram showing the convex side face up, the plot thickens!

It's true that the new isolator kit has a smaller diameter bolt, but that can be remedied with a larger replacement, or with a sleeve to make up the difference, if you are so inclined.

Why would Buell, immediately prior to its untimely demise under HD, spend large amounts of time on research, development and testing of a new isolator kit (and for tubers that had been out of production for 7 years at that point!!!) if the old one were just fine? I tend to believe that there was a problem with the older design, and the new design, without the D washer, was created to address this.

Having said this, the idea of supporting the front of the engine by bolting it to an underslung, rubber isolator held to the frame by two small bolts seems fairly ludicrous (this is the installation method shown for non-notched tube-frames, such as on the S2, shown in the Badweb photos). For the non-notched frames, I think I'd feel better using the old design.
Author:  Maz [ 14 Feb 2011 02:31 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
:roll: .......only reason the 'new kit' exists is that it uses a common H-D mount (thus the 7/16 bore compared to the Buell 1/2) ie. the Buell specific mount is no longer economically viable to produce........smoke and mirrors mate :idea:

Pash :roll: :roll: ....you think too much mate, or maybe not enough !........look at how your Buell works and you may just understand why Erik fitted the D washer convex upwards :headbang:
Author:  pash [ 14 Feb 2011 07:37 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
Maz wrote:
Pash :roll: :roll: ....you think too much mate, or maybe not enough !........look at how your Buell works and you may just understand why Erik fitted the D washer convex upwards :headbang:


Yeah, so, the Buell works by having an engine that hangs from the frame, which is prevented from moving side to side by tie rods. It still has two degrees of freedom, back and forth and up and down. Out of balance is caused by the pistons compressing, the cylinders firing, the acceleration/deceleration of the pistons and rods plus any mass induced out of balance on the crankshaft, this induces an acceleration in these two degrees of freedom as the cylinders at 22.5deg to the vertical.

Is this understanding correct so far?

Now, the inner of the rubber mount is bonded to a metal sleeve which bolts to the engine, and the outer to a plate which bolts to the frame. This rubber gives a rising rate spring and damper effect which is the isolation.

By putting the washer on with the convex side downwards, you get the same spring and damping coefficients up and down and you also have movement fore and aft. Put it the other way up, and you have a higher spring rate downwards and you restrict the fore and aft movement.

Now, lets look at the other things:

1. The D-washer is flat one side, and convex the other. Why go to the complexity of making a washer like that when a flat one would do?
2. The D-washer has a flat edge to prevent clashing with the headstock, the rubber doesn't, this suggests that the washer sits much higher than the rubber.
3. The manual (S1) and parts book (S1 and X1) actually depict the counterbored side facing upwards (however a 2001 manual shows no counterbore and no convex side).
4. Look at the design of the XB mount, the spring/damper effect is the same in both directions.

So, where is my thinking off track?

kevmean wrote:
My X1 is as per picture 2 and is the original factory fitted mount ;)


Not that it makes any difference, Muffin is broken, unloved and forgotten ;)
Author:  gunter [ 14 Feb 2011 08:13 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
I don't think that it is D-shaped to prevent collision, as there's no key to fix the washer's position. IMNSHO a clever chinese manufacturer had a faulty output, but no one at Buell ever recognized (how? no QC) and next time they ordered the same part "as last time".
Author:  bueller ball breaker [ 14 Feb 2011 09:41 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
Bring back the Stenzel bar lOl

http://www.r-r-customizing.de/xtshop/in ... uetze.html
Author:  Maz [ 14 Feb 2011 23:12 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
Righto Pash, seems yer still struggling.........XB and tuber front isolators are subject to completely different forces :idea: ........hint, consider how the rear suspensions work on these two models :twisted:
Author:  pash [ 14 Feb 2011 23:58 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
OK, I can buy that...

The questions I still have no answers to are:

1. why have a convex washer in the first place? A flat one would be much cheaper...
2. why cut a flat on the edge of the washer?
3. why print a service manual and many parts books with the convex side of the washer pointing downwards?
Author:  Maz [ 15 Feb 2011 00:21 ]
Post subject:  Re: Tuber Front Isolator - Ask the audience...
To avoid contact with the headstock ie. study the shape of the isolator both above/below the frame.......under hard acceleration the outer dia.of the rubber stays with the frame whilst the isolators inner sleeve moves upwards and the rubber deforms accordingly,the D washer moves up and forward towards the headstock.
Even though the flat presents a higher profile the fact that it's convex means this is less than a flat washer.......it also means that muppets who may not appreciate why the counterbore is present under the washer, can readily identify which way is up lOl .
As for service and parts manual inaccuracys........was that a serious question ? :rofl:
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