Torquing Confessions

[Air4Life]

I'm a little embarrassed to pass this on because I should know better... but if it helps someone else then maybe its worth it.

Its almost a year that I've had the r65 and I have added roughly 11K miles on it since then.  I recently checked the torque on the engine mounts and found them to be grossly under-torqued.  

After putting them at the value recommended on snow bums site, I went off for a ride on the highway.  When I say the bike is like a new bike, I'm not exaggerating.  The r65 vibration that has been reported by others and is said to be inherent in these machines was very uncomfortable, but not knowing what to compare it to I just assumed that was how it was.  It used to be  so annoying that I would lift the pressure off my feet if I was stuck in the 65- 68 mph range for an extended period.  Now that I've brought them up to spec., I can stay at that speed range and any other, and if I didn't know that the vibration existed, I would never know it.  Its far more comfortable to ride now.

 

[Rob Valdez 79 R65]

 

[k_enn]

Glad it is better for you.  I have heard from several sources that the infamous vibration in the 4,000 to 5,000 range is related to how tightly torqued the engine mounts are.  Also, supposedly it is not just the absolute torque value, but also related to a differential in the torque on various bolts.  They say the vibration never goes completely away, but with some minor changes in the torque it can be shifted to a different rpm band.  

k_enn

[Ron_S.]

Oh good!  Something else for me to fiddle with on my bike.   8-)

[Barry]

I have heard from several sources that the infamous vibration in the 4,000 to 5,000 range is related to how tightly torqued the engine mounts are.Also, supposedly it is not just the absolute torque value, but also related to a differential in the torque on various bolts.They say the vibration never goes completely away, but with some minor changes in the torque it can be shifted to a different rpm band.
 

That's been my experience. I'm using slightly lower figures than stock.  45ftlbs on the front and 40ftlbs on the rear which is similar to the 40ftlbs specified for the 85 on models. I found it reduced the vibration level slightly and shifted it up the rev range.

It's long been known that the same engine can feel more vibratory in one frame than another. It may be that the typical band of high speed vibration is not just a direct result of the engine having higher vibration levels at that speed but that it also corresponds with a resonant frequency of the frame/engine structure. Anything which changes the coupling between engine and frame even slightly may change the resonant frequency. Hence a change of frame or the tension on the engine mounts can alter perceived vibration levels.

It goes without saying that there is no point in playing with engine mounts unless the carbs are perfectly balanced first.

[suecanada]

Hi there Ron! Ron and I probably heard a number of riders at the Sedalia National say that they used to own an R65 but moved on from it because of excess vibration. Yeah, I guess it is a fact but I find LRB quite reasonable. Sure I feel some around 4600 to 4800 but the only way I know I feel it there is that at over 5000rpm it is so smooth in comparison. The Bonnie vibrates too and the worse offender was the '05 F650GS single. I had worse vibs on the original R65LS I owned back in '84. Your engine mount idea may have some merit alright...other than providing another something to do for Ron!!