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Discussion Starter #1
The other day on the way coming back from Phoenix, which is mostly uphill so under more of a load, I noticed I was getting a significant increase in what felt like engine vibrations.

Has anyone else on an X bike noticed this? If not then I may have a loose engine mount bolt somewhere but thought I'd ask first. What else could cause this? I don't think it's an out of balance tire simply because I don't feel it when going downhill over 80 mph. What about the timing wheel? Could that be causing it?

I have an Auto Tune unit and PC-V. Do you think there might be something happening there to cause this?

Thanks in advance to anyone with ideas or input.
 

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Not under those conditions, but is it a moderate frequency, say like a big cell phone?
If so you are running lean in that condition. Might back off the timing advance in the higher range on the PC or increase your fuel a bit.

Shooting in the dark, but I finally figured out the vibe I had that wasn't supposed to be there and no one had ever heard of.

I'll bet someone out there knows. Hard to dx over the internet.

cheers
 

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I get vibes in the neighborhood of 80 mph too. I have a Lloydz VFCIII--should I be changing a high speed setting?
 

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Can't say Rick. Mine started with the timing wheel and all I asked said it wouldn't do that. Hmmm, well it did.

I was reading some banter between Half Crazy and someone, and it suggested a lean condition even though the AFR+ should have taken care of it. It was probably at the AF ratio I set it at, but needed a little more gas. Mine was at all speeds and the engine heads were smooth but the passenger floor boards would almost make your hand go numb when touched. It was in the frame somehow.

I blamed the timing wheel for the vibe, but it seemed all said I was nuts, well no argument, but beside the point. I took it out and the vibe was gone. When I put in the Lloydz air filter it went ape again and fuel increase on cruise and acceleration seemed to have fixed it.

Just the experience of one as far as I know, and my bike seems to have some atypical quirks at times.
 

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Maybe a call to Lloydz will tell us if its the timing wheel or not. I'll do it and post what they have to say.
 

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Saying you are not getting the vibration going downhill at 80 tells us nothing about when you are getting it. Need some more information here otherwise it's just guessing.

If it's engine, you should get the same vibration at the applicable speed in any gear at which the rpm and load are the same as you are experiencing it at. Also what is the rpm and speed? The Vics like to run at a higher than usual rpm for some other vtwins. Is it just lugging?

Also note that harmonics can change the way you feel vibrations from a tire problem. Something evident at 60 may not be as noticeable at 80.

Fuel, timing, wires, plugs, etc. A few things here could be the source.
 

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I made the call and got someone who is apparently new as he had to put me on hold and came bake with "take it to your dealer." I will email Lloyd directly--he always responds with good info.
 

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Saying you are not getting the vibration going downhill at 80 tells us nothing about when you are getting it. Need some more information here otherwise it's just guessing.

If it's engine, you should get the same vibration at the applicable speed in any gear at which the rpm and load are the same as you are experiencing it at. Also what is the rpm and speed? The Vics like to run at a higher than usual rpm for some other vtwins. Is it just lugging?
Yes and no. Saying that it happens uphill but not down tells us it's happening when under load which is an important data point. While your follow up comment is correct, replicating the same engine rpm and load in different gears isn't exactly easy in most circumstances. Lower gears are going to produce more torque to the wheel resulting in acceleration (and thus engine speed change) unless a much steeper hill is found.

I would say that fueling/timing could definitely be the issue if the problem occurs under a specific load. That condition implies a specific throttle position and engine speed which are the two governing factors for many aftermarket fuel managers like the pc-v.

Since you have an auto-tune i'm assuming you have not had a dyno shop build you a custom map so the possibility of a lean spot in your map is there. If there is a dyno shop near you you could put the bike on there for diagnostic purposes. Have them use the dyno brake to hold the bike's speed steady while they add more throttle until the vibration occurs, then check the a/f ratio at that point in the map and see if it's lean. If so, add a bit more fuel there and see if it's fixed.
 

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Discussion Starter #9
Thanks everyone. Some really good info and things to consider. I should have mentioned that at 80 mph my rpm is right around 3k give or take. It should be the same for every X bike unless there is a change in rear tire diameter.

I really don't think this a tire issue. I will definitely post the results when I find the issue and thanks Ric for contacting Lloyd. He is the master of all things engine related for sure.
 

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Au contrare....tire balance can dial in to high speed vibes. When I went from the OEM E3s to Avon Cobras, I also went from Ride-On to DynaBeads resulting in far less high speed vibes. My very experienced tire guy said he has backed off of installing Ride-On because of customer complaints of failure to seal and balance problems.
 

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BBob theoretically under a load (going up hill) a electrical system will tell you if there is a bad plug, or wire loose, or a border line plug wire. such a miss fire will show during rpm like a vibration which you can feel .. Like holding the brake on a car and loading up the foot pedal. If a plug is bad in a car it will show up as a definite miss fire or running rough. So I say that to say look for a bad plug or boarder line connection. I hope you find it keep us post. Just a thought. Seeing how your at 80 and 3000 may eliminate this theory
 

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Au contrare....tire balance can dial in to high speed vibes. When I went from the OEM E3s to Avon Cobras, I also went from Ride-On to DynaBeads resulting in far less high speed vibes. My very experienced tire guy said he has backed off of installing Ride-On because of customer complaints of failure to seal and balance problems.
True, but tire vibrations are unlikely to be linked to engine load. That sort of issue is generally only rotational speed dependent.
 

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Does this only happen going uphill? Does it occur at other speeds on flat ground? Have you noticed this under other circumstances?

Need to have more situation knowledge to truly diagnose this. If it was only that road and only uphill I would be more inclined to attribute this to the road, unbalanced load or just some air dynamics.
 

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Is there less vibration if you downshift going up a hill?
 

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BBob
If you have the PCV w auto tune, check your trims at the rpm and throttle position. I'll bet there was some changes at that area. Apply the trims and add a little extra and ride the hill again.
 

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Hello all. I'll chime in on this discussion.

What I notice at around 75ish MPH is that my mirrors are shaking to the point I see blurry cars behind me (i.e. is that a police car or regular car?). If I reach up with my hand and grab the mirror, it stills and the picture is clear.

I have timing wheel, VFC-III, Lloydz air filter and D&D exhaust. I'm guessing something is throwing it a bit off balance?
 

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I find the comments from XC owners about their vibrating and blurry mirrors very interesting. The stock mirrors on my XR have never blurred, even when I had terrible balance problems with the original tires. Are XC mirrors mounted on springs?
 

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I find the comments from XC owners about their vibrating and blurry mirrors very interesting. The stock mirrors on my XR have never blurred, even when I had terrible balance problems with the original tires. Are XC mirrors mounted on springs?

I've never experienced any mirror vibration at any speed on my XC. My only mods are the Llyodz timing wheel (+4) and thrush mod exhaust.


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I've never experienced any mirror vibration at any speed on my XC.
Some do and some don't Theja. My point was that I have yet to hear from an XR owner about blurry mirrors.
 
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