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Twin Cam RT "Twist Protection" ?

Posted: Wed Nov 11, 2020 7:57 pm
by Our Gee
Further to my post regarding the removal of the Spark Plug covers, which I have now accomplished (thanks David for the info and video), when I removed the nearside Valve Cover a "lump" of rubber about the size of a Match Box fell out into my oil pan. I don't recall this item being present on my Hex Head. Looking at the Parts Fiche I note that this item is listed as "Twist Protection". Anyone know what is the purpose of this and just how is it supposed to be located.
Thanks.

Re: Twin Cam RT "Twist Protection" ?

Posted: Wed Nov 11, 2020 8:35 pm
by Kim_Y
Can you supply a photo of the item, this could be helpful?

Re: Twin Cam RT "Twist Protection" ?

Posted: Wed Nov 11, 2020 8:43 pm
by David.
This photo shows what in the Haynes manual on page 2.19, illustrations 7.6a & 7.9 is described as a "support block".

It just says, "Ensure the support block is pressed firmly into position".

Image

There is no explanation as to the purpose of this support block. Perhaps it helps to prevent "twisting" of the camshaft holder.

Re: Twin Cam RT "Twist Protection" ?

Posted: Wed Nov 11, 2020 8:57 pm
by David.
The parts list shows #5, twist protection for both the right & left cylinders.

Image

Re: Twin Cam RT "Twist Protection" ?

Posted: Wed Nov 11, 2020 9:22 pm
by David.
In this video at 3.33 you can see the support block on the RHS cylinder, https://www.youtube.com/watch?v=bRy0yL8g1VA

This video shows the LHS cylinder, at 1.58 the block moves as the valve clearance is checked, https://www.youtube.com/watch?v=AjH3fjCsR1A

Re: Twin Cam RT "Twist Protection" ?

Posted: Fri Nov 13, 2020 7:48 am
by Our Gee
What we need is someone from the BMW design team to come along and tell us just what is being stopped from Twisting by the "Twist Protection" , why it was deemed necessary and just how on earth is it supposed to secured in place and what would happen if it where left out during re-assembly ?. Could it be another example just like the lump of Sponge which was fitted inside the lower Alternator Cover which served no purpose other than to provide the nice moist wet area necessary to aid corrosion. Or am I being facetious !!.

Re: Twin Cam RT "Twist Protection" ?

Posted: Fri Nov 13, 2020 7:50 am
by David.
Could always ask your local BMW Motorrad dealer, they'll know for certain!