Bike "swerving" with high speed acceleration.

[txknight67]

I have searched this forum for a bit and couldn't find anything about this issue I'm having. When I am above 60mph, drop into 4th to pass someone, and roll on the throttle quickly, my '08 Spyder starts to squirm/oscillate/swerve. If I back out of the throttle, it goes away. It's intermittent though and I can't pin down all the external variables such as did I change lanes every time, am I in a curve, pavement type, etc.

Almost 99% sure I have not just changed lanes every time. In fact it happened just last week and I was already in the left lane and some one was messing with me, so I kicked it down a gear and gave the throttle full twist. I actually stayed on the throttle and it almost became uncontrollable. I rolled off the throttle and pulled into the right hand lane, but it was swerving/oscillating so bad it continued for a few seconds. I got a DPS light and a VSS light and it went into limp mode. Pulled in the clutch, turned off ignition, turned ignition back on, restarted bike and the VSS light stayed off, but the DPS light stayed on and it kept scrolling DPS FAIL or CHECK DPS, I can't remember and don't have my book right handy at the moment. Eventually even that light went out after several on and off cycles of the ignition and has stayed out.

I do know this, any time I stop the belt is still in the same place on the sprocket. I got a good adjustment last time and my belt has not moved since I changed the tire last. So, to me that should count out swing arm bushings or axle bearings. I am at a loss as to what is causing this. I can't even tell which end of the bike is causing it. I thought it was from the back, but this latest incident felt like the front tires were "dancing", working back and forth, not the back end.

I have automotive tires at all three corners, I'm running OEM pressure in all three (just checked after this latest incident and all were good) and this issue just showed up in the last three months and I have been running automotive tires for over 2 years. When I first went to automotive tires I played with pressures and settled in on OEM specs. Best wear on the tires with no adverse handling effects. (until now) This last back tire has been on there right around a year. Maybe the side walls are shot on that tire?

 

[NancysToy]

Check to see that the rear axle nut is properly torqued. After that, check the swingarm bushings and rear wheel/sprocket bearings. Don't romp on the throttle until you get to the root of this problem...your life depends on it.

 

[Ga Blue Knight]

Could possibly be that one or both of your brake pads are set too close to the rotor. Brake pads make light contact with the rotor some times. As they heat up at high speed they may engage on one side causing a drift to that side when you let off of the throttle. Under full throttle this is hidden by the power of the real wheel. Just a suggestion and easy to check. Lift a wheel off of the ground, you may need a jack (LOL), and see if it spins freely without dragging on the brakes. Second idea also involves the front brakes. If pad wear is very uneven you may get different braking effort for each wheel, this will also cause issues with tracking. Hope you to the bottom of this issue!

 

[Bob Denman]

It could also be a simple case of what happens to you on top of the bike...
You grab the loud grip, the bike starts to accelerate, those forces move you back in the saddle, you grab on tighter, and impart some steering inputs that you're not aware of...
Try pulling your knees in on the tank to steady yourself a bit more solidly and see if that helps...

 

[pellcitypete]

I had a similar problem on my first trip. after loading and reloading 2 or 4 times after we got on the road I noticed the same thing but not just when speeding up.When we got on hiway the more we went the worst it got.(so bad I was shaking when I got stoped) checked tire pressure on all 3 (ok) lugs all tight then it hit me(or it was my wife) that the shocks were to soft!! adjusted them tighter 2 notches. solved the problem.2,500 miles latter when we got home liked the stiffer ride so left it that way. hope this helps Pete

 

[Arr MiHardies]

He mentioned this is an 08. Might he still be needing the DPS computer update?thought that was one thing the update was supposed to help with. I'd go the the dealer and make sure everything is up to date. Failing that, give it a looser grip.

 

[boborgera]

He mentioned this is an 08. Might he still be needing the DPS computer update?thought that was one thing the update was supposed to help with. I'd go the the dealer and make sure everything is up to date. Failing that, give it a looser grip.

:agree: My 08 would do the same before the DPS RECALL,[not an update, About Two years ago]
Never did it again after they put in a new improved DPS.

 

[Illinois Boy]

It also simply could be when downshifting you loosen the tire's traction, and then when you suddenly accelerate it let loose even more... causing the rear-end to fish-tail somewhat before you let-off the throttle to get traction again.

Stabilize the Spyder before passing by downshifting first while staying in your lane until the bike stabilizes, then you can roll-on the accelerator to pass.

Or, simply do not downshift...

Just a thought.

 

[Firefly]

Wondering if this will be another thread where someone posts a problem--- many offer ideas and solutions---- only to never hear anything back from the OP.

No offense to the OP.. but it's been a week now and no further info shared....... or responses to the various ideas.

I just don't get it when this happens.... if you take the time to post details about a problem--- check back in to see what people have to say-- and please post back--- especially if you finally find the cause of the problem.

One obvious thing is that the OP needs to have the DPS checked....along with some other things.... battery and connections too....

 

[txknight67]

I had a similar problem on my first trip. after loading and reloading 2 or 4 times after we got on the road I noticed the same thing but not just when speeding up.When we got on hiway the more we went the worst it got.(so bad I was shaking when I got stoped) checked tire pressure on all 3 (ok) lugs all tight then it hit me(or it was my wife) that the shocks were to soft!! adjusted them tighter 2 notches. solved the problem.2,500 miles latter when we got home liked the stiffer ride so left it that way. hope this helps Pete

Thanks for the tip. Got to looking myself and started noticing that it seems like the left front has more "give" in the shock than the right. They are both set to the same setting though. I was thinking of taking one or both? of them up a notch. Thought I read somewhere on here very early that someone said adjusting to different settings leads to EVIL handling. :shocked:

Starting to wonder if I have a bad shock. No oil leaking though.

 

[txknight67]

It could also be a simple case of what happens to you on top of the bike...
You grab the loud grip, the bike starts to accelerate, those forces move you back in the saddle, you grab on tighter, and impart some steering inputs that you're not aware of...
Try pulling your knees in on the tank to steady yourself a bit more solidly and see if that helps...

Thought of this the first time it happened, so have paid more attention. Don't do anything different between the times it does oscillate and the times it doesn't. Thanks for the suggestion.

 

[txknight67]

Wondering if this will be another thread where someone posts a problem--- many offer ideas and solutions---- only to never hear anything back from the OP.

No offense to the OP.. but it's been a week now and no further info shared....... or responses to the various ideas.

I just don't get it when this happens.... if you take the time to post details about a problem--- check back in to see what people have to say-- and please post back--- especially if you finally find the cause of the problem.

One obvious thing is that the OP needs to have the DPS checked....along with some other things.... battery and connections too....

Went on a weeks vacation and was pretty busy. Plus my computer got jacked to be used for crossword puzzle answer look up by my brother and mom. :banghead:

 

[txknight67]

Other info

Thought of some other pertinent info after I posted this. Years don't mean a whole lot with a tire. pps: Back tire has 12000+ mi on it.

Also, had new DPS installed very soon after they became available and update done at the same time. Last time I bought parts, ~3 months ago, dealer looked up my VIN and said that according to his computer my bike is current on all updates. The thought crossed my mind that it still could be the DPS. Motor may have just worn out. I ride my bike like I stole it. :roflblack:

Going to get the back tire changed and obviously check all the bearings while I'm in there. Give it time to see what it does, then take the shocks up a notch if it still keeps happening. If that doesn't fix it, probably will change both front shocks. If that doesn't fix it, it is off to the dealer with it.

 

[Firefly]

Thought of some other pertinent info after I posted this. Years don't mean a whole lot with a tire. pps: Back tire has 12000+ mi on it.

Also, had new DPS installed very soon after they became available and update done at the same time. Last time I bought parts, ~3 months ago, dealer looked up my VIN and said that according to his computer my bike is current on all updates. The thought crossed my mind that it still could be the DPS. Motor may have just worn out. I ride my bike like I stole it. :roflblack:

Going to get the back tire changed and obviously check all the bearings while I'm in there. Give it time to see what it does, then take the shocks up a notch if it still keeps happening. If that doesn't fix it, probably will change both front shocks. If that doesn't fix it, it is off to the dealer with it.

They had various DPS updates that were done once the recalls started......I had mine replaced a few times with the new programming--- but the problem never got fixed 'for good' until the NEW version of DPS was released and installed--- this was a good year or so after the initial recall.

There used to be a way to tell if you had the newer type of DPS from looking from underneath at it--- but I can't remember how.... do a search out here and maybe you can find a photo showing it.

 

[txknight67]

Issue located!

Took off the back wheel to change the tire and discovered that the wheel hub bearing and the sprocket bearing had "wallowed" out where they were supposed to be press fit. Didn't think to take pictures until after I had already given the parts to my brother for scrap aluminum recycling. The bearing assembly's themselves were in good shape though....not that it makes any difference, just thought I'd throw that out there.

Only thing I can think, is that the axle nut didn't get torqued last time the tire was changed. Still somewhat baffles me that the belt was not wandering all over the sprocket with the bearings that messed up. $570+ later, the bike should be back on the road tomorrow.

 

[Bob Denman]

:shocked: Ouch!
Well I hope that this solves the problem!
Please let us know, and good luck! :thumbup: