Vibration

[DewCatTea-Bob]

[quote= Scrambler ...
" I found the motor mounts snug. BUT the top rear was not really tight, it took a 1/4 ~ 1/3 of a snug and the vibration went away. It was a huge difference for such a small amount of torque/tightness. "

____ Very worthy thread-post content, posted by Mike (on the previous-page) !
__ Although not too easy to believe that merely-just a third of a turn of a single motor-mount nut could make such a noticeable difference, I do however know that the regular/normal-vibration can become changed into very-NOTICEABLE relatively severe-VIBRATION whenever any two motor-mount bolts lose their minimum intended torque-setting !
__ The stock-type 8mm.lock-nuts (which came in either 13 or 14mm hex-sizes) really can't be relied-on to permanently hold their set torque-setting and-so shouldn't be trusted to do so !
I-myself would choose to rather use six-pairs of 8mm nuts to replace all six of the original nylon-type lock-nuts...
First, (on my-own project-DUKEs),, I'd install 14mm.hex-nuts which include their-own built-in shoulder-washer (with overall OD of about 16mm), and-then MIGHTLY-torque them down to just a few ft/lbs less than the amount which would otherwise strip the threads,, then-next, install rather-plain 12mm*hex-nuts torqued-down & jammed-up-against the 14mm.nuts (to help keep them all locked-up in their final-set position). _ That way,, not-only would the motor-mount bolts be more sure to stay-put & remain fully-tightened, but also, IF-&-when a quick-look at the mounting-nuts revealed a missing 12mm.nut, I'd then rather-conveniently & handily be made aware that THAT particular motor-mount bolt-position has become in need of resetting, (so as to help prevent that which Nick has also mentioned about the hole-enlargement issue, [before any extra engine-vibration gets a chance to contribute towards !]) !
(* The 14 & 12mm combo of hex-nuts is so that they can be rather more conveniently tool-tightened separately.)
__ So next-time anyone is dealing with ya'r Duke-rider's motor-mount bolts, be sure to then at-least consider replacing the original lock-nuts with my recommended jammed-together double-nut suggestion !


Hopeful-Cheers,
DCT-Bob

[Bevel bob]

I have suffered heavy vibration from the tank and lost bolts, I have just completed a modification to the front mountings to include rubber gromets and alloy spacers which allows the bolts to be fully tightened but still allow tank movement, works a treat. Modification as suggested by Stewart.

[pear0]

I will check them again. Hope that I find a loose one. Thanks to all.

[DewCatTea-Bob]

[quote= pear0 ...
" Hope that I find a loose one. "

____ The locking-method of the stock nylon-type lock-nuts is only good for keeping them from becoming unscrewed & lost, and not so good for maintaining their originally-set torque-setting. _ So when you've found such a mounting-nut that can be further torqued-down another half-turn (or more),, then rather than settle for merely-just that, you really ought-to consider replacing it with a pair of replacement nuts that you can jam-together (after the first-one has been fully torqued-down).
That way, you won't end-up redoing THAT-one again next-time you have-to check for another loosened mounting-bolt (that's still held merely by a single stock lock-nut).


Hopeful-Cheers,
-Bob