Suspension Issue: Bike Stands Up In Turn

[Jiggles]

Sure wish there was some general tech section to put this that wasn't limited to 250s hint hint wink hint wink

I was just going to pm Jason to help me on this but I figure I'll post it in case some other stupid idiot can learn from it. And hey, maybe one of you stupid idiots will have some insight as well!

N E weigh

The Issue

When I'm in a turn with my ninja 1000 the bike wants to stand back up, i.e. the front wheel is trying to turn into the turn and bring the bike back up. I have to maintain a constant pressure on the inside bar in order to hold the line. If I try to be weightless on the bars the bike will right itself back up. Another interesting aspect is that this is more noticeable on left turns than on right turns. Left turns require more pressure to stay turning.

Observations

This happens at any speed and on any radius turn, even very mild bends. The more I lean the more severe it is and the more pressure is required to hold the line. I should also note that initiating a turn on this bike is extremely easy, even easier than on the 250. I attribute this phenomenon to the higher bars and much steeper rake (the rake is steeper than even the zx10 )

If I accelerate hard in a turn then the pressure required becomes less severe.

My 250 doesn't do this, I can remove pressure from the bars and it will hold its line without any input.

Solutions

Here's what I've tried so far. Keep in mind the issue isn't fixed, just less severe with each modification.

• Putting the correct tire pressure in made it better
• I increased the preload on the rear and forks which made it better*
• I increased the front preload from 7 turns in to 12 turns in (of 15 turns in total) I then tried increasing the preload from 12 to 14 which made it significantly worse so I changed it back to 12
• Rear preload went from 4 to 8 (of 10 total) I'm going to put it to 10 today to see if it helps
• Swapped from a 190/50 rear (which is described to me as an abortion of a tire) to a 190/55 which made it much better
• Took it to a suspension guy, he noted that my preload settings and sag were dead on, my rear wheel was perfectly aligned and he wasn't entirely sure what was causing the issue. He also adjust the rebound damping force on front and back
• Spoke with an ex-AMA racer who said its supposed to behave this way and I need to not put pressure on the inside bar in a turn, instead I should try a downward force on the bar. Tried it, if I don't put force the bike starts to straighten up in a turn. He was also the one that suggested the 190/55 rear

Bike Setup
Front Preload: 12/15
Rear Preload: 8/10
Front Tire: 120/70
Rear Tire: 190/55

At this point I'd like to ask @rojoracing53 to ride my n1k and hopefully through his myriad of complaints "I hate kawis, the shifter sucks, the brakes suck, its too heavy, its too fat, the slipper clutch is crap ", hopefully, I can figure out the problem. Maybe its supposed to behave this way? Maybe I'm imagining the left feeling different from the right? Maybe a new front? Maybe maybe maybe, who knows but maybe he can help

The goal is to get the bike to require no steering input while turning

If anyone else has suggestions I'd be happy to hear them. However, if all you've ever ridden is a 250 then you are useless and should feel terrible about yourself.

[csmith12]

hmmm.... this sounds strangely familiar.

Possibilities:
Front brake dragging
Warped rotor
Heavy throttle hand maybe

[Jiggles]

Heavy throttle hand nah, bike has 2000 mi think it could have a warped rotor already? How would I tell if the front brake is dragging?

[Alex]

Originally Posted by Jiggles

[*]Took it to a suspension guy, he noted that my preload settings and sag were dead on, my rear wheel was perfectly aligned and he wasn't entirely sure what was causing the issue. He also adjust the rebound damping force on front and back

If you've already done that, and the guy was any good, then any suggestions on tweaking suspension settings here probably won't move things in the right direction.

What it sometimes comes down to is tire profile. How rounded it is, whether it is smoothly rounded or more sharply angled, has a large effect on steering feel and front end behavior when leaned over. Different bikes respond differently to different tire setups, and different riders prefer different profiles even on the same bike. Michelin makes different front tires with the same compound to deal with things like this, some more rounded and some called V profile (which as may be guessed, is more pointed rather than rounded). What front tire is on it now, the OEM? Which 190/55 did you put on the back?

[Jiggles]

I got an S20 for the back, the front is still OEM (bt016 I believe) though they did try talking me into another s20 for the front, saying that it would help things even more (I wasn't so sure about that so passed it up for now)

As they explained it to me, the reason the 55 series felt much better is because it raised the rear. I was also told thats why increasing the rear preload to 8 made it feel better and even though the sag is correct right now, raising the preload to 10 and thus raising the rear some more should make it feel better.

Although now I'm wondering, is this working towards fixing the problem or simply countering the symptoms of the problem.

[Bigballsofpaint]

Ive read raising the front 5mm helps a lot too, i dont push the bike hard yet so i dont pay enough attention to the settings. Its def not as easy to handle as the 250, and im not gonna switch tires until the stockers are done, im too poor to throw away a good set.

[csmith12]

Originally Posted by Jiggles

Heavy throttle hand nah, bike has 2000 mi think it could have a warped rotor already? How would I tell if the front brake is dragging?

Simply throw it on the front stand and spin the wheel yo. Should get a couple of rotations from an easy spin with your hand. If you can't 100% for sure tell, put some space between the pads and rotor and spin it again. Everything should be dead nuts and straight (wheel & rotor).

I have run both your every day street tires with a more round profile and the cups (V profile). My bike (R6) holds it's line with either tire. Just throwing that out there for comparison.

[Jiggles]

Originally Posted by Bigballsofpaint

Ive read raising the front 5mm helps a lot too, i dont push the bike hard yet so i dont pay enough attention to the settings. Its def not as easy to handle as the 250, and im not gonna switch tires until the stockers are done, im too poor to throw away a good set.

Do you notice needing to continue applying pressure to the bars while in a turn?

I've heard its a common problem on the n1k though it is usually remedied by a 55 rear. My problem got better but still persists

[rojoracing53]

Originally Posted by Jiggles

At this point I'd like to ask @rojoracing53 to ride my n1k and hopefully through his myriad of complaints "I hate kawis, the shifter sucks, the brakes suck, its too heavy, its too fat, the slipper clutch is crap ", hopefully, I can figure out the problem. Maybe its supposed to behave this way? Maybe I'm imagining the left feeling different from the right? Maybe a new front? Maybe maybe maybe, who knows but maybe he can help

^This

I'm off work now but still at the shop for the next few hours finishing up my front brake mod. So I didn't read the whole post yet but I will later. Bring it on over and ill ride your ***** like I stole her

[Jiggles]

Originally Posted by csmith12

Simply throw it on the front stand and spin the wheel yo. Should get a couple of rotations from an easy spin with your hand. If you can't 100% for sure tell, put some space between the pads and rotor and spin it again. Everything should be dead nuts and straight (wheel & rotor).

I have run both your every day street tires with a more round profile and the cups (V profile). My bike (R6) holds it's line with either tire. Just throwing that out there for comparison.

Idk if my front stand will support the weight but I guess I'll try that.

Talking to the ex-AMA guy, he said stuff like I'm experiencing tended to be more common with people on 1000s who came from 600s. I think he was talking more about racing though whereas this happens on the smallest street curves

[Jiggles]

Originally Posted by rojoracing53

^This

I'm off work now but still at the shop for the next few hours finishing up my front brake mod. So I didn't read the whole post yet but I will later. Bring it on over and ill ride your ***** like I stole her

I'm pretty much booked till next week unless you want to come on this group ride on saturday and ride it there. Next week I'm off tues, wed, and thur so I can come down any of those days

[DaBlue1]

Bigger, heavier bikes with wider tires require a little more steering input at slower speeds (bike geometry also plays a roll), so your observation is correct ("If I accelerate hard in a turn then the pressure required becomes less severe.") What you are trying to achieve is neutral steering, which requires ZERO steering input to maintain a turn once it has started. Suspension inputs can effect this to a small degree, but speed will affect it more.

Here is a good piece of info on Neutral Steering.

[rojoracing53]

You need this

Link to original page on YouTube.

[Jiggles]

Originally Posted by DaBlue1

Bigger, heavier bikes with wider tires require a little more steering input at slower speeds (bike geometry also plays a roll), so your observation is correct ("If I accelerate hard in a turn then the pressure required becomes less severe.") What you are trying to achieve is neutral steering, which requires ZERO steering input to maintain a turn once it has started. Suspension inputs can effect this to a small degree, but speed will affect it more.

Here is a good piece of info on Neutral Steering.

I do still notice it at higher speeds but I'm not sure if it's less severe. I'll make a note of it the next time I try.

I see what you mean on the neutral steering, what I really mean is that I want the bike to take a minuscule amount of force to maintain the turn. Like you know how when you ride the street and initiate turns, you really don't feel like you are making steering inputs even though you really are. I want it to that degree, whereas now its like damn, I'm really pushing on this bar hard just to stay turning

[alex.s]

what is "correct" when it comes to this kind of steering? what makes a bike stand up in a turn? if you have correctly set trail and wheelbase the bike should be neutral steering. if however something changes the trail or wheelbase, the way the bike steers will be effected. nonstandard tire sizes/profiles? stretched swingarm? low tire pressure? with a big bike, throttle effects suspension considerably. what is the throttle position of the bike when it is trying to stand up? are you slowing or accelerating?

if a wheel is dragging for one of a variety of reasons (rolling resistance caused by low tire pressure, wheel bearings, chain drag, improper use of throttle/engine brake, etc) the geometry of the bike will again be effected (forks compress, rake decreases, etc) and the bike will again no longer be neutral steering.


i would try putting a few pounds in your front tire and see how it is effected. try spinning the wheels while its on the stand... dragging? bearing noise? anything messed up? check your geometry and that the frame is straight... simple string true up should be good

[Jiggles]

Originally Posted by alex.s

what is "correct" when it comes to this kind of steering? what makes a bike stand up in a turn? if you have correctly set trail and wheelbase the bike should be neutral steering. if however something changes the trail or wheelbase, the way the bike steers will be effected. nonstandard tire sizes/profiles? stretched swingarm? low tire pressure? with a big bike, throttle effects suspension considerably. what is the throttle position of the bike when it is trying to stand up? are you slowing or accelerating?

if a wheel is dragging for one of a variety of reasons (rolling resistance caused by low tire pressure, wheel bearings, chain drag, improper use of throttle/engine brake, etc) the geometry of the bike will again be effected (forks compress, rake decreases, etc) and the bike will again no longer be neutral steering.

On the street most of the time in turns I'm maintaining a constant speed and I feel it. If I accelerate hard (think significantly exceeding speed limits in a second or two). Then I notice it's much less severe tho still noticeable

[alex.s]

constant speed through a turn should require slight pressure... accelerating smartly should be neutral steering. see suggestions in previous post

[DaBlue1]

Originally Posted by Jiggles

I do still notice it at higher speeds but I'm not sure if it's less severe. I'll make a note of it the next time I try.

I see what you mean on the neutral steering, what I really mean is that I want the bike to take a minuscule amount of force to maintain the turn. Like you know how when you ride the street and initiate turns, you really don't feel like you are making steering inputs even though you really are. I want it to that degree, whereas now its like damn, I'm really pushing on this bar hard just to stay turning

I think as you get more used to the N1K, you may find it gets easier and the 250 way too easy and light.

[Jiggles]

Originally Posted by alex.s

constant speed through a turn should require slight pressure... accelerating smartly should be neutral steering. see suggestions in previous post

To me, this doesn't feel like slight pressure which is why I want Jason's second opinion it. Maybe that is how it is supposed to feel but I don't think it is.

The front tire is already at the max. Increasing it to the max made the problem less severe.

I'll try spinning on the stand when I get a chance (likely tomorrow)

and the suspension guy already confirmed the wheels are aligned (bar method)

[csmith12]

Originally Posted by Jiggles

To me, this doesn't feel like slight pressure which is why I want Jason's second opinion it. Maybe that is how it is supposed to feel but I don't think it is.

The front tire is already at the max. Increasing it to the max made the problem less severe.

I'll try spinning on the stand when I get a chance (likely tomorrow)

and the suspension guy already confirmed the wheels are aligned (bar method)

Have Jason ride it.

And just because the wheels seem to be in line with each other doesn't mean the front wheel is "straight". Ever hit any bumps hard? Maybe hard enough to tweak the front wheel? Have Jason check the front wheel for straightness, since you have it in the air.

[alex.s]

if the front end was twisted it would be hard one way, but dangerously easy the other way. it would always try to tip that direction just a bit even when going straight.

if you want to cover up the issue without really knowing the underlying cause, you can raise the forks in the clamps to get a steeper rake... will make turning the bike easier but the bike will be more unstable (trys to stand up less)

[csmith12]

Originally Posted by alex.s

if the front end was twisted it would be hard one way, but dangerously easy the other way. it would always try to tip that direction just a bit even when going straight.

if you want to cover up the issue without really knowing the underlying cause, you can raise the forks in the clamps to get a steeper rake... will make turning the bike easier but the bike will be more unstable (trys to stand up less)

You think so? hmmmm.... I am not so sure my friend. I am willing to learn something new.

Imma do a vid of the straightness of my front and rear wheels on my R6. I will do the street set of wheels. They are untrue as they come and she still cuts like a laser and holds it until the most gentle of push either way. The white ones in my avatar... yep, even rode them on the track.

Ignore this until I get the vid, as it's apple to oranges comparison anyway but should still be interesting none the less.

[alex.s]

not sure about the wheels being true i just mean the axis of rotation twisted in relation to the triples. if the wheels weren't true, they would wobble back and forth as they rotate so it shouldn't effect steering that much (outside of the annoying vibration/wobble)

[csmith12]

Yea, that is what I mean, the wobble.

[Lychee]

Maybe one of the forks is twisted within the clamps. That doesn't usually happen unless the bike has gone down, but it is probably worth the 10 minutes to undo and redo all the top fork clamp bolts and then the bottom fork clamp bolts.

[alex.s]

maybe vought hit another poor 17 year old...

[Jiggles]

Yea that's thing, haven't crashed at all...

[Motofool]

Originally Posted by Alex

If you've already done that, and the guy was any good, then any suggestions on tweaking suspension settings here probably won't move things in the right direction.

What it sometimes comes down to is tire profile. How rounded it is, whether it is smoothly rounded or more sharply angled, has a large effect on steering feel and front end behavior when leaned over. Different bikes respond differently to different tire setups, and different riders prefer different profiles even on the same bike. Michelin makes different front tires with the same compound to deal with things like this, some more rounded and some called V profile (which as may be guessed, is more pointed rather than rounded). What front tire is on it now, the OEM? Which 190/55 did you put on the back?

Originally Posted by alex.s

what is "correct" when it comes to this kind of steering? what makes a bike stand up in a turn? if you have correctly set trail and wheelbase the bike should be neutral steering. if however something changes the trail or wheelbase, the way the bike steers will be effected. nonstandard tire sizes/profiles? stretched swingarm? low tire pressure? with a big bike, throttle effects suspension considerably. what is the throttle position of the bike when it is trying to stand up? are you slowing or accelerating?

if a wheel is dragging for one of a variety of reasons (rolling resistance caused by low tire pressure, wheel bearings, chain drag, improper use of throttle/engine brake, etc) the geometry of the bike will again be effected (forks compress, rake decreases, etc) and the bike will again no longer be neutral steering.


i would try putting a few pounds in your front tire and see how it is effected. try spinning the wheels while its on the stand... dragging? bearing noise? anything messed up? check your geometry and that the frame is straight... simple string true up should be good

Both Alex's have explained the problem correctly, IMHO.
The suspension has nothing to do with this problem.
It is related to subtle changes in steering geometry and tire characteristics.

Jiggle's bike is now under-steering:

Read pages 111, 112 and 317:

http://books.google.com/books?id=rJT...page&q&f=false

"Tires have a large influence over bike handling, especially on motorcycles. Tires influence bike dynamics in two distinct ways: finite crown radius and force generation. Increase the crown radius of the front tire has been shown to decrease the size or eliminate self stability. Increasing the crown radius of the rear tire has the opposite effect, but to a lesser degree.

Tire inflation pressures have also been found to be important variables in the behavior of a motorcycle at high speeds. Because the front and rear tires can have different slip angles due to weight distribution, tire properties, etc., bikes can experience understeer or oversteer. Of the two, understeer, in which the front wheel slides more than the rear wheel, is more dangerous since front wheel steering is critical for maintaining balance. When understeering, the steering angle must be greater, and when oversteering, the steering angle must be less than it would be if the slip angles were equal to maintain a given turn radius."

[rojoracing53]

Holy **** I check back 5 hours later and we're 30 posts deep and I still haven't read the first one

I'll look this over and let you know what I think in the morning since I'm going cross eye as I type. Also I cant make that ride tomorrow so I'll catch you another time. Be safe out and have fun with the BARF group tomorrow.

[rojoracing53]

Originally Posted by Jiggles

At this point I'd like to ask @rojoracing53 to ride my n1k.

If we swapped bikes I'd be worried about whether or not you could handle raw exhilarating epic response and handling that is the Rojoracing Special Edition Yamasaki 250

[Bigballsofpaint]

Jigs i can say i do feel i need to try a little more in the turns, but i still have the stock 50 series tire and havent messed with suspension. I also havent really been pushing the bike through the curves, only straights. I bought the bike a week before Xmas, so most of the riding ive been doing is near freezing or freezing temps. So im not pushing it too hard

[skilletmo]

Solution: Ride the 250. GG

[Jiggles]

Originally Posted by rojoracing53

If we swapped bikes I'd be worried about whether or not you could handle raw exhilarating epic response and handling that is the Rojoracing Special Edition Yamasaki 250

My 250 puts down 31 steroid enhanced ponies, I think I can handle it

[TheDementedDrummer]

The monster did the same thing after my dad crashed it, it didn't like to turn right. left was fine, in comparison.
The guys at the dealership said it was because the rebound on the front forks was different, or something

[Jiggles]

Maybe it was crashed before I bought it!?!?

[geeker]

From http://www.motorcycledaily.com/2011/...test-part-two/

When I was seriously considering a Ninja 1000, I saw multiple reviews and forum topics that mentioned a 180 tire on the press bike prior to launch. At launch they changed to a 190 rear. Are you rotating the bars on the same axis as the rotation, or or are you literally pushing down on the bars?

You could take the approach we did, or you could try something different (something we may try when we switch tires). You could go with a higher profile rear tire. The Ninja 1000 comes stock with a 190/50 section rear, and you could swap to a 55 section rear (either 190 or 180) to provide a bit more ride height in the back, and also a better tire profile for tipping the bike in the corners. By raising the forks, the Ninja 1000 not only changes directions more easily, it tracks better, whether in a straight line or through corners.

[Jiggles]

What do you mean? I rotate the bars normal

[geeker]

Originally Posted by Jiggles

What do you mean? I rotate the bars normal

Are you rotating the forks with your forearms level to the turning axis or are you sitting up and pushing down towards the road? If it's the latter, it requires more effort.

[geeker]

This vs...

[geeker]

This.