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Thumping from the floor boards


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This is hard to explain but I'll give it a try.  When riding I can hit bumps and obviously feel them through the handle bars and sometimes the foot boards, other times I'm not so much going over a bump but more of a dip or transition from a bridge back to pavement and it is a slight rise, but it's smooth for the most part, I feel nothing in the bars but I still feel like something thumped the bottom of the bike and I feel it in the boards.  The best way to imagine it is if I had a rubber mallet attached to the bottom on a spring and sometimes it has enough tension to swing up and hit the bottom.  I know bad example, but I can't seem to figure it out and this has been an issue for a while now and no one can seem to "recreate it" yet I can everytime I leave the service shop.  Anyone having this experience?  To me I almost thought it was a motor mount that when I went over these dips and such that the motor was slightly moving but they swear they have checked them each time I mention it and still nothing. 

And then a new development, I was starting to get a wobble when I would make turns, like at an intersection leaving a light or stop sign and it would have a bit of a wobble as I was turning, but straight it was fine.  I thought since it was time for a new tire I would get a new one, did so and now I have a slight wobble on the front all the time now.  Some how they let it go like that saying it was all good . . . thoughts? 

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@dragonstorm    Yup! Check the tightness of your steering head nut. The “thunk” is from the movement. The fact you’re now having cornering problems confirms this.  These are the most stable bikes in corners even two up and pushing it hard.  Long ago I had a similar “thunk” noise as you described and found the nut loose.

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2 hours ago, dragonstorm said:

This is hard to explain but I'll give it a try.  When riding I can hit bumps and obviously feel them through the handle bars and sometimes the foot boards, other times I'm not so much going over a bump but more of a dip or transition from a bridge back to pavement and it is a slight rise, but it's smooth for the most part, I feel nothing in the bars but I still feel like something thumped the bottom of the bike and I feel it in the boards.  The best way to imagine it is if I had a rubber mallet attached to the bottom on a spring and sometimes it has enough tension to swing up and hit the bottom.  I know bad example, but I can't seem to figure it out and this has been an issue for a while now and no one can seem to "recreate it" yet I can everytime I leave the service shop.  Anyone having this experience?  To me I almost thought it was a motor mount that when I went over these dips and such that the motor was slightly moving but they swear they have checked them each time I mention it and still nothing. 

And then a new development, I was starting to get a wobble when I would make turns, like at an intersection leaving a light or stop sign and it would have a bit of a wobble as I was turning, but straight it was fine.  I thought since it was time for a new tire I would get a new one, did so and now I have a slight wobble on the front all the time now.  Some how they let it go like that saying it was all good . . . thoughts? 

Can you duplicate it by tapping on the front brake? Get er goin about 30,, pull the front brake ONLY in hard enough and quickly enough that it makes the bike jump/respond.. Listen/feel carefully and see if it does it.. If it does, watch the neck area/nut on top of triple clamp.. If, as Chief mentions, nut is loose retorque BUT do not discount or over look possible loose neck bearing spec.. Watch area below top clamp at bearings too!! Also,, what are you doing for new front tire balance? Are you now using beads? Did you add anything inside of tire that was not in there when new - like anti flat stuff?  

They said it was ok like that? A Yamaha shop?  Write a sheet of paper up stating they will be responsible if an accident occurs due to front end wobble turning into the death wobble - it happens!! Make it look professional! Have them sign it.. They will back peddle LOL.. 

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  • 3 weeks later...

Ok, so . . . I took it back to the dealer and they "think" they found a small lump in the brand new front tire and replaced it.  They also say they loosened all the steering bolts, front and rear axles and retightened everything and had me come get it and take it out to test it.  The thump is gone for the most part but I still feel it when I go over larger bumps and some larger transitions but I now feel it when it is the back tire going over the said bumps.  So replacing the tire removed the wobble which is great, but now they created something new.  While riding around 70-75 I feel a vibration oscillating from left to right in the handle bars.  I will feel it in the left, the right then gone and repeats.  At those speeds it is roughly a 2 second rotation on, it's not horrible but it's new and shouldn't be there and if I take my hand off one of the bars and I see it vibrate pretty good.  They, however, can't seem to feel it and pretty much have washed their hands of it, told me to take it somewhere else to get a second opinion and if they find something to come let them know what it was . . . I was thinking sure thing, I'll give them the bill for the other shop too.  😕  Plus it appears they screwed up the lid for the gas cap it now rattles and sits crooked.  

Any thoughts now on the oscillation?  

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2 hours ago, dragonstorm said:

Ok, so . . . I took it back to the dealer and they "think" they found a small lump in the brand new front tire and replaced it.  They also say they loosened all the steering bolts, front and rear axles and retightened everything and had me come get it and take it out to test it.  The thump is gone for the most part but I still feel it when I go over larger bumps and some larger transitions but I now feel it when it is the back tire going over the said bumps.  So replacing the tire removed the wobble which is great, but now they created something new.  While riding around 70-75 I feel a vibration oscillating from left to right in the handle bars.  I will feel it in the left, the right then gone and repeats.  At those speeds it is roughly a 2 second rotation on, it's not horrible but it's new and shouldn't be there and if I take my hand off one of the bars and I see it vibrate pretty good.  They, however, can't seem to feel it and pretty much have washed their hands of it, told me to take it somewhere else to get a second opinion and if they find something to come let them know what it was . . . I was thinking sure thing, I'll give them the bill for the other shop too.  😕  Plus it appears they screwed up the lid for the gas cap it now rattles and sits crooked.  

Any thoughts now on the oscillation?  

Double check your tire air pressures with a gauge, do not depend on your TPMS if you have one.  Check the tires when they are cold, what pressures are you running and what pressure does it say on the tire(s) carcesses?.  Are you by any chance running balancing beads or run flat or anything else inside the tire?  Does it make a difference on what road/road surface you are riding on @dragonstorm?  Try several road surfaces noting if there is a difference.  If you look at the sidewall of the tire(s) where they meet the rim you will notice a raised edge on the tire, that is an alignment edge to show the mounter of the tire that the tire is mounted properly.  Examine your tires and make sure that little edge is exposed all the way around the wheel so you know the tire is mounted properly.  High speed, 70ish mph, "wobble, wonderings" are often attributable to neck bearing setting.  Personally, I have my own method for setting neck bearings that is NOT "by the manual" that has served me well thru the years so I cannot speak to your torque spec for your bike BUT, you should be able to find that setting in a service manual.  Is it possible that the dealership loosened or changed the neck bearing adjustment when he loosened all those bolts? Did you get a reciept of any form stating what was done? If so and it were mine I would look carefully on that receipt and see if such an adjustment was done. If so, it really might not be a bad idea to have that checked at another dealership as all dealership are not necessarily created equal,,, ALL IMHO of course..

Puc

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I, oddly didn't get anything stating that since there was no charge, I don't know that they even put anything in the system stating for sure what they did, I will check, but yes I believe they did loosen that as a part of trying to "reset" everything and then retightened back up to spec.  The oscillation is obviously more noticeable on smoother surfaces, like freshly paved so very little bumps and you can really tell the vibration is from something off, but on older roads where the bumps are more prevalent then it would be hard to tell.  The thumping, like I said has substantially been reduced with all the loosening and tightening they did, but it's more on the rougher roads now, but I have only had it out for about 60-80 miles since they did the work, so I might be able to get out this week or later this weekend and see what is going on.  I will check the tires and the pressure with a gauge, the TPMS says 38/38 when i left the dealership yesterday, by the time I got home it was 40/40.  I think it's supposed to be 41/41 but I will check.  Thanks for the input.  

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