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Bad vibrations

murf

murf

Active Member
Well here goes...back around April I removed the mid mount footboards and brake and shift levers and went to forward controls. 2 days later I noticed a slight vibration in the whole bike as I shifted up through the gears. Gradually got worse and leveled off to a constant and predictable vibration. What I mean by that is about halfway through each gear as I accelerated the vibe would show itself then go away after I shifted to the next gear and came back about halfway through that gear, etc. I don't hot rod my bike. in 5th gear it would come in around 55 mph. I was told my motor mounts were ok. But I recently found my front lower motor mount had been oil soaked repeatedly over the years and when I replaced it the rubber was soft and cracking. I now have a new OEM style mount installed and the vibration did not go away, it did change though. Now it vibrates, maybe worse now, from standing start to the point of other things rattling. It seems to diminish as speed increases. I'm told I'm probably not hurting the bike but I can't imagine this being good for long or short term. HELP !!!:bigsmiley15:
 
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Not knowing "just" how much vibration you are expecting. Your motor mounts was a good start, make sure all fasteners are torqued to spec. as well as go through list of "critical fasteners" for your bike. My first thought after this is to ensure both cylinders are "pulling" their weight evenly. Since the engine is basically an IC air pump...check the plugs for "even" burning...check compression for "even" filling and cylinder condition...check ignition spark (grounding the opposite plug not being tested for "visually" equal spark...! Right now my mind is just jumping, sorry but doing a garage sale in 85* heat and posting at the same time.
 
murf said:
Well here goes...back around April I removed the mid mount footboards and brake and shift levers and went to forward controls. 2 days later I noticed a slight vibration in the whole bike as I shifted up through the gears. Gradually got worse and leveled off to a constant and predictable vibration. What I mean by that is about halfway through each gear as I accelerated the vibe would show itself then go away after I shifted to the next gear and came back about halfway through that gear, etc. I don't hot rod my bike. in 5th gear it would come in around 55 mph. I was told my motor mounts were ok. But I recently found my front lower motor mount had been oil soaked repeatedly over the years and when I replaced it the rubber was soft and cracking. I now have a new OEM style mount installed and the vibration did not go away, it did change though. Now it vibrates, maybe worse now, from standing start to the point of other things rattling. It seems to diminish as speed increases. I'm told I'm probably not hurting the bike but I can't imagine this being good for long or short term. HELP !!!:bigsmiley15:
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I had the exact same issue as you do at one point and I about pulled my hair trying to get it worked out. I found that no matter what I did, I could not get rid of it. I too looked at all of my mounts, went through the bike to make sure all things were tight and I just could not get it. I am assuming that since you do not hot rod your bike, that you have everything pretty much stock? I found that since I did baffle my bike I was getting reversion and that was the cause of my vibration. There were other issues that I was having as well, but am convinced that since I had no baffles, that was the culprit.

I would go out and just pound on the bike. it is possible that you have a lot of carbon build up that can affect certain areas of the engine. I would use the highest octane gas that your bike can stand, use some Sea-foam and go hot rodding for a tank worth, then see how it acts....:D
 
Is it possible that something in the forward controls is touching the engine somewhere, allowing vibrations to transmit? Is the exhaust system completely isolated from the frame? If anything is touching the engine and frame, it could be causing the vibration.
 
The vibration is, for lack of a better word, a "deep" one. By that I mean it is not a "light" vibration caused by something touching something else. My front mount was the original one from new. I assume the rear one is also. I'm not a tech so it's not like I have a wealth of experience in this. I did neglect to mention the issue I'm experiencing with my trans. It has on a couple of occasions while in second gear running over the washboard surface of the gravel road leading to my house, shifted from second to first on it's own. But only during the ride on that road and nowhere else. I think my next step, or two, is to make sure the engine, trans and frame are aligned properly and then perhaps the rear mount or the top one. I firmly believe that this is a heavy part, mount or something of that nature, issue. Would appreciate any tips on how to align the drive train with my linited selection of tools. Thanks for all the input. I want to get back to "good vibrations".
 
If that is indeed the original front motor mount this could be the cause of some of the vibration. Since you went to forward controls your feet are pressing more on the controls and that mount is very close to the front controls. Change out the rubber mount on the front and make sure all the mounts are torqued to spec. I'm not sure how your swingarm mounts, but if it is isolated with rubber it's time to change them also.
 
Thanks Don, I'm thinking along those same lines that this is a mount/alignment issue and will be replacing all the mounts as money allows. I still think aligning the eng. trans. is a good idea.
 
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