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Discussion Starter #1
So I recently got new wheels from Honda with the new spokes, so used the chance to do my Tubeless conversion with 3M tape and sealant and put on some Pirelli Scorpion Rally STR's. Super happy with the tires, have already tested a bit offroad and they work amazingly on the road. Give loads of confidence.
BUT
I feel sometimes like the front end is bouncing/vibrating too much. This is especially apparent between around 25-45mph. Below or above this, it seems to disappear. If I take my hands off the bars between 25-45, the bars shake and wiggle quite a bit. Feels like going over a very consistently rough road. What could this be?


I don't think it's the tires because they aren't that aggressive. I had the wheels changed and balanced at Honda so that should be ok.


Could Honda have given me wheels where the spokes aren't adjusted properly? Is a bouncing feeling a symptom of having spokes that are too tight maybe? When I ping them, they sound more on the dull side than high pitched, which is what got me wondering. But then if it was a bounce from the spokes not being right, this probably wouldn't go away at higher speeds, it would get worse.


Happy to be told it's just the tires. It's my first bike with non street tires. Thanks
 

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My 2017 DCT does the same thing. No matter how I tried to adjust the forks, I haven't been able to stop it to my satisfaction. These are not my first fully adjustable forks, so I have experience with this and yes I even take notes. I also checked the balance of the stock front tire and it was off just under a 1/2 oz, so I fixed that. Still bouncing. Now I have new springs on order from Cogent. I may also increase the weight of the oil in the forks to better compensate for my sevlte 255 lbs frame. I'll report back when I have more.
 

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Discussion Starter #3
My 2017 DCT does the same thing. No matter how I tried to adjust the forks, I haven't been able to stop it to my satisfaction. These are not my first fully adjustable forks, so I have experience with this and yes I even take notes. I also checked the balance of the stock front tire and it was off just under a 1/2 oz, so I fixed that. Still bouncing. Now I have new springs on order from Cogent. I may also increase the weight of the oil in the forks to better compensate for my sevlte 255 lbs frame. I'll report back when I have more.
When you checked the balance did you also check the trueness of the rim?
 

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Not specifically, but I did not notice any out of roundness when I had it on the static balancer. I have done enough tires over the years that I'm sure I would've noticed any. I did balance it out and it didn't make any difference. I really believe that the springs are too weak, flacid in the small movement zone and correspondingly the dampening can't control the bounce. When, the forks hit a bigger bump the dampening works well enough. Maybe even just a thicker fork oil might do the trick. If you compare any of the aftermarket springs to the stock Honda ones you will find a much more robust spring.
 

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My 2019 ATAS manual is doing the same
thing. In the 30 mph range the bike bounces up and down. It smooths out at higher speeds but it doesn’t seem to be a normal thing.
 

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Every 21 inch front wheel bike I personally have owned does the same thing just like my 2016 does. I don't know why.
 

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Discussion Starter #7
So I've found a bit of a flat spot on the rims, which is likely to be giving the bounce. Although still weird that it doesn't bounce at all speeds. The tire is perfectly balanced. Honda don't seem to think adjusting the spokes will round out the flat bit. Seems it could be a factory issue with the mold, or possibly the tire I have. Not sure what to think but Honda don't seem keen on adjusting the spokes and in a bit hesitant to try myself... definitely didn't have this with the original tires and rims though so has to be one of the two
 

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Make sure the front axle is seated properly and that the forks are not binding. I recently replace the tires and had the same thing, along with the front end popping up from a stop, I went thru the front wheel mounting procedure again making sure to really compress the forks before tightening the pinch bolts and they are both gone.
 

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Find exactly what mph it starts doing it - then upshift and see if the speed it is doing it at changes. If it does - then the engine vibration is matching with the wheel vibration and they are amplifying each other. Make sure your air pressure isn't too high.
 

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Yesterday I changed out the front springs with the .72 kg springs from Cogent Dynamics. Being close to the 260 lbs weight that Cogent lists on their web site for the .82 kg springs I initially ordered the .82's. Speaking with Cogent I learned that the .82's have been replaced with .80's because people found the .82's to be to stiff. While discussing my riding style, back roads, nothing hard core off road, Cogent felt that I would be better served with their .72's. While I was changing the springs I also changed the fork oil to a 12.5 weight, achieved by mixing one quart each of 10w and 15w. Result, I'm very pleased. The front is much tighter with less fork dive. The bike corners much better, the forks feel stronger with less flex. The bounce that I was experiencing has been greatly reduced, I still need to tweak the rebound and compression to see if I can dial it in more. Next time I change the fork oil I may try a straight 15w. The Cogent springs are a straight swap out, you don't need to change anything else. They are also a much beefier straight rate rather than the the wimpy Honda progressives. Finally, at 255 lbs the .72's are plenty strong for my purposes and I can't imagine needing the .80's.
 

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.

Make sure the front axle is seated properly and that the forks are not binding. I recently replace the tires and had the same thing, along with the front end popping up from a stop, I went thru the front wheel mounting procedure again making sure to really compress the forks before tightening the pinch bolts and they are both gone.

Torque Request- When you say you compressed the forks before tightening the pinch bolts, do you mean you didn't tighten the left pinch bolts AT ALL before tightening the axle bolt? The manual calls for tightening the left pinch bolts, then the axle, then loosening the left pinch bolts, tightening the right ones and then tightening the left ones again. I have the same bounce issue after changing the tires.and I'm wondering if doing the axle first might help as you suggest, but wanted to make sure I was understanding your post.
 

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Front wheel installation

Torque Request- When you say you compressed the forks before tightening the pinch bolts, do you mean you didn't tighten the left pinch bolts AT ALL before tightening the axle bolt? The manual calls for tightening the left pinch bolts, then the axle, then loosening the left pinch bolts, tightening the right ones and then tightening the left ones again. I have the same bounce issue after changing the tires.and I'm wondering if doing the axle first might help as you suggest, but wanted to make sure I was understanding your post.
You can torque the axle nut without tightening any axle pinch bolts
if you use a hex bit to keep the axle from spinning while torqueing to spec.
The installation steps from the manual: with the assumption you are not using a 17 mm hex bit to hold the axle- you are using the RHS pinch bolts instead.
If you use a hex bit to torque the axle nut, you can skip to step 4.
The point is to align the RHS fork with the LHS fork fixed.

1. Tighten the right front axle holder pinch bolts to the specified torque.
2. Install and tighten the axle nut to the specified torque.
3. Loosen the right front axle holder pinch bolts.
4. Tighten the left front axle holder pinch bolts to the specified torque.
5. Install the front brake calipers.

With the front brake applied, pump the forks up and
down several times to seat the axle and check brake operation.


6. Tighten the right front axle holder pinch bolts to the specified torque.


ED model: Install the axle cap.
Check the clearance gap between the front wheel
speed sensor bracket and pulser ring (page 20-21).
 

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I followed the manual directions (which i find much more complicated than any "dirt bike" that I have ever had). When time to compress the forks I started the engine and gave it some good compressions under throttle. Finished tightening per the manual.

I think originally that I missed one of the tightening/loosening steps of the pinch bolts (as I would have on any of my dirt bikes) and I was weak on the compress step (much easier to do on a dirt bike).

100 mies of mixed terrain and I no longer feel the front wheel hop at slower speeds or the front end popping up when acceleration from a stop.
 

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Great advice here. I had no issues with the stock dunlops. I had bounce around 30mph and 70+mph once I fitted the motoz GPS so I thought surly it must be balancing..... Nope. Had some loose spokes, nope. Ran lower pressures... Better. Finally played with suspension. I softened front compression and maxed rear preload. My 70+ went away (that was the one bothering me the most) the 30 is still there. I'm just living with it at this point. It's unaffected by anything other than speed. (neutral, gear) tho it goes away under braking. From looking closely while spinning the front rim, I think there's a flat spot causing it. I did properly seat the axle.

Just my experience, not much help, but I'll be curious to see what my next set of tires do..... Or I may need some wheel work.
 

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Hi people, I registered juuust to take part in the discussion here. I had a similar problem on a used AT I test drove at a dealer, it had a similar bounce (up and down) from the forks at the same speed as the OP. I was wondering if this was just this particular bike or some kind of quirk. The bike felt stable on the highway but on smooth pavement I had that bounce, it has shinko 804/805 tires so quite knobby.. I'm at the point where I'm not sure to get the bike because of that and try to work the quick out, because everything else seemed fine to me.
 

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DCTFan posted a pretty good guide on how to fix it, also Shinko's are the ****, probably the best tire to get other than Bridgestone Battlax AX41's for a 50/50 tire. If the bike is a good deal, I would get it because the problem seems to be a quick fix.
 

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You can torque the axle nut without tightening any axle pinch bolts
if you use a hex bit to keep the axle from spinning while torqueing to spec.
The installation steps from the manual: with the assumption you are not using a 17 mm hex bit to hold the axle- you are using the RHS pinch bolts instead.
If you use a hex bit to torque the axle nut, you can skip to step 4.
The point is to align the RHS fork with the LHS fork fixed.

1. Tighten the right front axle holder pinch bolts to the specified torque.
2. Install and tighten the axle nut to the specified torque.
3. Loosen the right front axle holder pinch bolts.
4. Tighten the left front axle holder pinch bolts to the specified torque.
5. Install the front brake calipers.

With the front brake applied, pump the forks up and
down several times to seat the axle and check brake operation.


6. Tighten the right front axle holder pinch bolts to the specified torque.


ED model: Install the axle cap.
Check the clearance gap between the front wheel
speed sensor bracket and pulser ring (page 20-21).

Will give that a try. I too experience the same bouncing at the front end at slower speeds. Swapped bikes with my brother yesterday (FZ8) his front end felt like it was a bowling ball going over a perfect surface, my 2019 AT felt like it was going over a rough batch of road though it was new pavement. Fingers crossed, love this bike so much but that it annoying a low speeds. Initially I even thought it was from the engine compression when letting off the throttle, but even when pulling the clutch I'd still get that front bounce.
 

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I had the front end bounce also and I called Honda customer service last week about when my fuel pump may arrive and in the process asked about the front end bounce and he said following those torque guidelines above may help that bounce. Mine had loose axle pinch bolts that someone failed to tighten and I did it myself before I had read the repair manual. I saw another post here somewhere and that guy claimed all 21 in. Wheels are prone to that.
 

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I had the front end bounce also and I called Honda customer service last week about when my fuel pump may arrive and in the process asked about the front end bounce and he said following those torque guidelines above may help that bounce. Mine had loose axle pinch bolts that someone failed to tighten and I did it myself before I had read the repair manual. I saw another post here somewhere and that guy claimed all 21 in. Wheels are prone to that.
I've ridden quite a few bikes with 21" wheels and can't say I've experienced this on any other bike before.
 

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Yea seems to me if it’s perfectly round it shouldn’t be hopping up and down. My atas would do it even in neutral while coasting. The dealer said it was out of balance and hopefully it’s fixed now. I will know once it gets its new fuel pump.
 
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