flexing under hard acceleration

[Factor]

I'm pretty new to Valks although I've ridden 5 different ones in the past year. None of them exhibit the type of flexing I'm experiencing on my 99 tourer during hard acceleration. By 'Hard', I mean as in not coming off the throttle when flicking the clutch to grab the next gear. When the gear hits, I go forward a lot but also get a twisting - kind of wallowing motion in the rear end for a second or so.

Other than that the bike is solid - no shimmies, wobbles and anything really.

I have progressive air shocks on the back pumped up pretty good - 50 or so psi.

I do have a CT on the back now but this was happening before when a bike tire was on the back.

I probably go harder on my bike than the other four but I'm also wondering if I have an issue that I need to look into.

Is that normal?

[The emperor has no clothes]

It's not normal. At least I've never experienced any flexing like you are describing.

[greggh]

Have you inspected the rear dampners?
They might be wornout?

[Hook#3287]

What rear tire pressure?

[Bighead]

Shock bushings?

[WintrSol]

I've experienced something similar, but only when pulling away from a stop, with a 700# trailer. The torque on the rear drive changes the height of the rear seat, briefly. Hitting it really hard as you describe may cause the same kind of height change.

[Dr K]

Rode a Harley with a bad rear wheel bearing once it felt like I was going over tar filled cracks every time you would roll on or off the throttle ?

[sandy]

Softer shocks will help keep the back tire from breaking traction. You might be experiencing wheel hop. Try 30 PSI.

[John Schmidt]

Rear shocks at 50 psi?  Much too high unless you're coming in around 400 lbs. alone, even then it's not really necessary. You're not getting any real "shock" action at that level. If you're getting a wallowing sensation in back with hard acceleration, it's most likely a suspension issue somewhere that you're missing. Stuff happening in front will transmit to the rear in most cases, keep us posted on what you find.

[Factor]

Thanks for all the responses.

Shocks: I haven't taken anything apart yet for inspection. I figure the next step will be taking the rear wheel off to inspect the shock rubber mount bushings and look for any play in the swing arm bushings or even cracks in the swing arm.

Tire pressure: the same symptoms occurred with a motorcycle tire at 38 psi, a car tire at 34 psi and 40 psi (I went up in psi to reduce the jello feeling during slow turns).

Height change: that probably is happening but it's not even. One side is reacting differently to give a circular sensation as opposed to up/down. I've ridden shaft drive bikes for decades and this is not the typical high change.

Wheel bearing: there is no grind sensation or scowling noise but I will inspect them when I have the rear wheel off.

Wheel hop: It's not a sharp sensation but more of a rolling one with no sharp edges.

[old2soon]

My Virago would have the pinion climb the ring gear on hard acceleration. In effect raising the rear of the bike. Til I got used to it it were interesting. However my Valkyrie has never exhibited that. Without dumping the clutch I have pulled small wheelies on occasion with Phatt Ghurl. Worn Shock bushings I've noticed Will cause "stuff" to happen that ain't fun. Lotsa good suggestions. A follow up after yer situation is diagnosed would be helpful. RIDE SAFE.

[Factor]

I'll move to the front after I check the rear. I'll also bring down the rear psi.

I believe this bike has the OEM front springs - they're sagging quite a bit. I've been meaning to either upgrade to Progressives or at least put some spacers in to tighten them up.

I would have thought if it was in the front end that I'd be tank slapping under such hard acceleration but it always dissipates a second or so after hitting the next gear (when the change in torque is the greatest in the drive shaft). But then again, diagnosing frame harmonics can be a tricky affair.

[longrider]

Check your steering head bearing.  I set mine a hair tighter than specs.  If there is even a bit of play there it will transmit through the entire bike.  Under hard acceleration the forks will extend and then collapse as you shift so  setting up the bearing a bit tighter will dampen the steering.

[Gryphon Rider]

By 'Hard', I mean as in not coming off the throttle when flicking the clutch to grab the next gear. When the gear hits, I go forward a lot but also get a twisting - kind of wallowing motion in the rear end for a second or so.

Is that normal?

I might be mistaken, but I think most who responded missed this detail of what you said.

I don't think it's normal to NOT come off the throttle when shifting.  I would definitely recommend a quick flick of the wrist to get off the gas when changing gears.  Sorry, I would call what you are doing bad riding and a recipe for future repairs that most riders won't require.

[northernvalk]

By 'Hard', I mean as in not coming off the throttle when flicking the clutch to grab the next gear. When the gear hits, I go forward a lot but also get a twisting - kind of wallowing motion in the rear end for a second or so.

Is that normal?

I might be mistaken, but I think most who responded missed this detail of what you said.

I don't think it's normal to NOT come off the throttle when shifting.  I would definitely recommend a quick flick of the wrist to get off the gas when changing gears.  Sorry, I would call what you are doing bad riding and a recipe for future repairs that most riders won't require.

Otherwise known as power shifting...I think that those of us that do this, on occasion, know full well what we are doing. It's not an everyday occurrence, only used when facing an "opponent" of equal or greater acceleration!

[greggh]

By 'Hard', I mean as in not coming off the throttle when flicking the clutch to grab the next gear. When the gear hits, I go forward a lot but also get a twisting - kind of wallowing motion in the rear end for a second or so.

Is that normal?

I might be mistaken, but I think most who responded missed this detail of what you said.

I don't think it's normal to NOT come off the throttle when shifting.  I would definitely recommend a quick flick of the wrist to get off the gas when changing gears.  Sorry, I would call what you are doing bad riding and a recipe for future repairs that most riders won't require.

When I ride hard that is precisely how I shift, no throttle lag at all.
No premature wear on my parts at 120K.
mind you I dont ride hard all day or all the time.

[Gryphon Rider]

By 'Hard', I mean as in not coming off the throttle when flicking the clutch to grab the next gear. When the gear hits, I go forward a lot but also get a twisting - kind of wallowing motion in the rear end for a second or so.

Is that normal?

I might be mistaken, but I think most who responded missed this detail of what you said.

I don't think it's normal to NOT come off the throttle when shifting.  I would definitely recommend a quick flick of the wrist to get off the gas when changing gears.  Sorry, I would call what you are doing bad riding and a recipe for future repairs that most riders won't require.

Otherwise known as power shifting...I think that those of us that do this, on occasion, know full well what we are doing. It's not an everyday occurrence, only used when facing an "opponent" of equal or greater acceleration!

So then, do you experience the twisting/wallowing he describes?

[Houdini]

By 'Hard', I mean as in not coming off the throttle when flicking the clutch to grab the next gear. When the gear hits, I go forward a lot but also get a twisting - kind of wallowing motion in the rear end for a second or so.

Is that normal?

I might be mistaken, but I think most who responded missed this detail of what you said.

I don't think it's normal to NOT come off the throttle when shifting.  I would definitely recommend a quick flick of the wrist to get off the gas when changing gears.  Sorry, I would call what you are doing bad riding and a recipe for future repairs that most riders won't require.

Otherwise known as power shifting...I think that those of us that do this, on occasion, know full well what we are doing. It's not an everyday occurrence, only used when facing an "opponent" of equal or greater acceleration!

So then, do you experience the twisting/wallowing he describes?

I shift like this sometimes, usually play racing my friends, I honestly think what you're describing is just breaking the tire loose.  Mine doesn't squeal the tire, it just gets a little squirelly back there.

[greggh]

By 'Hard', I mean as in not coming off the throttle when flicking the clutch to grab the next gear. When the gear hits, I go forward a lot but also get a twisting - kind of wallowing motion in the rear end for a second or so.

Is that normal?

I might be mistaken, but I think most who responded missed this detail of what you said.

I don't think it's normal to NOT come off the throttle when shifting.  I would definitely recommend a quick flick of the wrist to get off the gas when changing gears.  Sorry, I would call what you are doing bad riding and a recipe for future repairs that most riders won't require.

Otherwise known as power shifting...I think that those of us that do this, on occasion, know full well what we are doing. It's not an everyday occurrence, only used when facing an "opponent" of equal or greater acceleration!

So then, do you experience the twisting/wallowing he describes?

No I have never experienced what is described.

I do experience be blinded at times from the headlights of the bikes I leave behind!   

[Chrisj CMA]

Been thinking about this so while out riding today I tried to make that flex thing happen.  I couldn't, but I have had shaft drive bikes since '79 and Valkyries since '02 so I am very used to a little shaft rise.  Could it be you are not used to the changes that happen because of the drive shaft?

[northernvalk]

By 'Hard', I mean as in not coming off the throttle when flicking the clutch to grab the next gear. When the gear hits, I go forward a lot but also get a twisting - kind of wallowing motion in the rear end for a second or so.

Is that normal?

I might be mistaken, but I think most who responded missed this detail of what you said.

I don't think it's normal to NOT come off the throttle when shifting.  I would definitely recommend a quick flick of the wrist to get off the gas when changing gears.  Sorry, I would call what you are doing bad riding and a recipe for future repairs that most riders won't require.

Otherwise known as power shifting...I think that those of us that do this, on occasion, know full well what we are doing. It's not an everyday occurrence, only used when facing an "opponent" of equal or greater acceleration!

So then, do you experience the twisting/wallowing he describes?

only shaft rise, which was wierd at first.

[Factor]

NorthernValk is right on target - I certainly don't get around power shifting all day. It'd be hard to hang on to a license for long - I tried that when I was 16 and made it all of 2 weeks.

I took the rear end apart today and found all my shock bushings in good shape.




The swing arm also had no play in it in any direction.

Then I took the drive star off the rear wheel and saw these funny wear marks between the shafts.




Which were put there but the bolt heads holding the damper plate down. That sure doesn't look right to me.




Taking a look at the outside edge of the dampers I can see there pretty worn in an uneven pattern resulting in a trapezoid of sorts. The dampers also fell right out.




So now I have a new set of o-rings, thrust washer and dampers for rebuilding the rear end. I'll repost when I get that back together and can try it out again.

Thanks for all the insight!

[gordonv]

Pictures? Since we've lost most/all of our old posts, we need new ones of these. This had happened before to someone, hub rubbing on the damper hold down plate.

[old2soon]

Also replace the ground down bolts that hold that plate on. While I am NOT sure the shock bushing shown in 3d pic from the left looks sketchy to me but it is a pic. I'm not right there with you. Was there a thrust washer where it was sposed to be on tear down? Thinkin yer problem has Been diagnosed!   Thankd fer the update. RIDE SAFE.

[Factor]

There was no thrust washer present which probably contributed to this.

[The emperor has no clothes]

There was no thrust washer present which probably contributed to this.

No probably about it. I would clean that wheel up real good and make sure it is not damaged. I think you got lucky, it looks ok.

[Skinhead]

It also looks like your progressive air shock in the first picture is blown out and leaking oil.  At least those look like progressives from what I can see of them.  I had this happen to my 2X, so I went back to OEM.

[gordonv]

It also looks like your progressive air shock in the first picture is blown out and leaking oil.

Pictures? I see no pictures. I looked over this post again, and there are no pictures posted. I've also noticed this before on other posts, mention of pictures, but I don't see any.

What am I missing (besides the pictures)?

[JimC]

Pictures? I see no pictures,
me either

Jim

[hubcapsc]

Pictures? I see no pictures,
me either

Jim

His pictures are on photostash... most of our browsers block photostash, it is on a blacklist.

-Mike

[greggh]

NorthernValk is right on target - I certainly don't get around power shifting all day. It'd be hard to hang on to a license for long - I tried that when I was 16 and made it all of 2 weeks.

I took the rear end apart today and found all my shock bushings in good shape.




The swing arm also had no play in it in any direction.

Then I took the drive star off the rear wheel and saw these funny wear marks between the shafts.




Which were put there but the bolt heads holding the damper plate down. That sure doesn't look right to me.




Taking a look at the outside edge of the dampers I can see there pretty worn in an uneven pattern resulting in a trapezoid of sorts. The dampers also fell right out.




So now I have a new set of o-rings, thrust washer and dampers for rebuilding the rear end. I'll repost when I get that back together and can try it out again.

Thanks for all the insight!

Glad you located the problem.

While you have it tore down that far......
Check the bearings and replace if you are not certain how long they have been in the.
Piece of mind goes a long ways!

[Factor]

Those are progressives. I'll look into what it takes to rebuild them - or go back to the oem's which I got from the PO.

Now I have two questions...

1) Pictures - what is the current most successful method to get pics loaded in threads?

2) Notifications - I'm set up to receive new unread responses to threads I'm signed up for (and I'm certainly signed up for this one as I created it) - but I have yet to receive and notifications. Not in my spam folder either. Here are my settings in Profile/Notifications and Email...

X Receive forum announcements and important notifications by email.
X Receive reply notification only for the first unread reply.
X Turn notification on when you post or reply to a topic.
O When sending notification of a reply to a topic, send the post in the email (but please don't reply to these emails.)

For topics and boards I've requested notification on, notify me of: Replies and Moderation

Any thoughts?

[The emperor has no clothes]

I can’t help with the notifications stuff, but I’ve been using postimage.org for pics.

[mellowyellow#7933]

In the pic showing the worn bolt heads is the wheel casting that holds the wheel bearing worn down? Looks like a small ridge then worn down. Should this area not be flat & even with the top of the wheel bearing? This could be caused by the missing thrust washer?
Edit: Look at pics in this thread  http://www.valkyrieforum.com/bbs/index.php/topic,39552.msg373513.html#msg373513

[..]

Those are progressives. I'll look into what it takes to rebuild them - or go back to the oem's which I got from the PO.

Now I have two questions...

1) Pictures - what is the current most successful method to get pics loaded in threads?

2) Notifications - I'm set up to receive new unread responses to threads I'm signed up for (and I'm certainly signed up for this one as I created it) - but I have yet to receive and notifications. Not in my spam folder either. Here are my settings in Profile/Notifications and Email...

X Receive forum announcements and important notifications by email.
X Receive reply notification only for the first unread reply.
X Turn notification on when you post or reply to a topic.
O When sending notification of a reply to a topic, send the post in the email (but please don't reply to these emails.)

For topics and boards I've requested notification on, notify me of: Replies and Moderation

Any thoughts?

HA TELL ME ABOUT NOTIFICATIONS.

Mine stopped a few weeks ago and since then I've received 3. I too have no idea WTF is going on.

For photos use https://postimages.org/

[Factor]

Thanks to mellowyellow for that link to the previous rear end issue. Those pics really help a lot. His case looks a lot worse than mine although I haven't taken a good cleaned look at the splines yet. My wheel bearings felt smooth and solid but replacing them is a good idea as well. I'll have to look closely at that apparent ridge on the surface of the hub under the thrust washer. I may not be out of the woods with just a new set of dampers 

[gordonv]

I'm not sure where you choose your notification options, but when I post/reply to a thread, under the edit window is an "Additional Options..." note. This is where I choose the notification option on this post only.

[The emperor has no clothes]

Thanks to mellowyellow for that link to the previous rear end issue. Those pics really help a lot. His case looks a lot worse than mine although I haven't taken a good cleaned look at the splines yet. My wheel bearings felt smooth and solid but replacing them is a good idea as well. I'll have to look closely at that apparent ridge on the surface of the hub under the thrust washer. I may not be out of the woods with just a new set of dampers 

Upon closer inspection of your pic, it appears the wheel is wore down below the face of the bearing. 

[Skinhead]

Thanks to mellowyellow for that link to the previous rear end issue. Those pics really help a lot. His case looks a lot worse than mine although I haven't taken a good cleaned look at the splines yet. My wheel bearings felt smooth and solid but replacing them is a good idea as well. I'll have to look closely at that apparent ridge on the surface of the hub under the thrust washer. I may not be out of the woods with just a new set of dampers 

Upon closer inspection of your pic, it appears the wheel is wore down below the face of the bearing. 

I agree that the hub appears to be worn, but you might be able to double up on the thrust washers and get by, If I didn't have a 2nd wheel handy, that's what I would do.

[Factor]

Upon closer inspection of your pic, it appears the wheel is wore down below the face of the bearing. 

This is what I'm hoping for but I've already started looking for replacement wheels.

under the edit window is an "Additional Options..."

This is already checked off for "Notify me of replies" as it should be.