How stable is your bike?

[raysigh]

Hey guys, 

I just purchased an FZ07, and the first time I gave it the beans, whenever I cut the throttle for an aggressive upshift, the whole bike would shimmy back and forth. This was more pronounced the faster I went, so I had to be very careful with how much input I was putting on the handlebars when upshifting like this. 

Nothing happens on it's on. If I release the handlebars, it's very stable. At speed it's stable as well. Only when I give the bars some sort of torque left/right at speed.

I suspected a few things:

1. Tires: bikes been ridden less than 5000 miles in 4 years and hasn't been on a stand. Possibly an unbalanced/lopsided tire.

2. Steering head bearing: however, I propped it up by the oil pan, and 0 notchiness was observed. Smooth from left to right. Could I maybe need to tighten the adjustment bolt?

2. Alignment: The swingarm markings were used for alignment by the looks of it. I measured the adjustment bolts protruding out, and they were about 1mm off. I then did the string method which was off by about 1cm. Adjusted the alignment to within 1mm at the front wheel via the string method.

Went for at test ride, and now I can't even remember how stable it should be having ridden this bike like this for a few weeks already

 

Question: If you give your handlebars a quick flick in one direction left/right, does your bike shimmy a bit before settling again?

[scat2me]

I've never had this problem. Of course I've never given it the beans. Try letting up on the beans

[mossrider]

Stop torquing the bars. 

Keep with the beans.

Problem solved.

 

Seriously, any time you jamb loads into the controls you're upsetting  the machines stability. The trick is to be smooth with your inputs. If shifting upsets the bike you're doing it wrong, or less than smoothly. All of those things you mention can contribute to an oscillation or weave or wobble but that anomaly would be primarily started with a gross input into the controls (which is sometimes caused by the road surface too). If you flick the bars it damn sure should respond, that's what it is supposed to do. And like you said, after an oscillation it should correct itself when the mechanicals are good.

[raysigh]

I should add a note here that I've been riding for 12+ years with 8 bikes (not bragging just saying this ain't my first rodeo), and I'm not putting excess torque on the handlebars when I shift. I'm surprised about the amount of instability I get from the bike when I'm upshifting BECAUSE this seems abnormal, and this hasn't happened with any bike in past.

[longrider1951]

This bike has a very short wheelbase and steering geometry (rake and trail) that leans towards aggressive, when you sit on it you can't see the front wheel. What this boils down to is you have to be a little more subtle with your steering inputs. That plus the suspension is not the best means you have to be smooth in all areas.

[Rider360]

Try sliding the fork tubes up 5mm. If you have a rear shock with adjustable ride height raise the back of the bike slightly. One full turn worked wonders on my 2019.

[shinyribs]

1 hour ago, Rider360 said:

Try sliding the fork tubes up 5mm. If you have a rear shock with adjustable ride height raise the back of the bike slightly. One full turn worked wonders on my 2019.

This would make the geometry more aggressive, not more stable. 

[Rider360]

It works believe it or not!

[clinical]

I haven't noticed exactly what you're describing, but if this bike isn't properly set-up it can be pretty unstable.  I'd start by checking/adjusting laden sag and going from there.  I have played the game on the highway, where I wiggle the bars and see how many oscillations it takes for the bike to recover depending on how far forward or aft I put my body weight.  I'd recommend doing the same a few times, noting how body positioning affects stability.  This should give you a clue how to set your preload for max stability. 

Edited September 21, 2020 by clinical
reworded

[raysigh]

I believe I've fixed the issue: I noticed the front wheel was slightly facing drivers left. 

So I aligned the rear (which I used the swingarm tickmarks for this).

Then I realigned the front wheel by... Slightly undoing the steering tube clamp (which normally on bikes is a nut on TOP, so it can be undone slightly without the forks and the steering column falling down). I undid it just enough to... hold it I guess (not actually sure what I was supposed to do about this). 

Undid lower triple tree pinch bolts, front fender, front axle and pinch bolt, brake calipers. 

Wheeled the front wheel onto a folded trash bag, and did CPR on the top of the forks about 12 times. Got off really carefully, and hand tightened the steering tube clamp and the rest of the loosened items in their respective order. 

 

Then I ran the string test again, which pissed me off because - if I made the rear wheel line up with the front wheel (and the frame itself just by standing back and looking), they did not line up with tickmarks on each side of the swingarm. Off by at least 1 line. The adjustment bolt lengths protruding outwards were also off.  

However, I trusted the string test with both sidewalls touching on the rears, and about 2.5mm from sidewall to string on all 4 corners of the strong tire (+/-1  to 2mm) 

 

 

Just went for a test ride without all the plastics (because I had to take the tank plastics to get a torque wrench onto the steering column nut), and I believe it's fixed. The bars have a much "heavier" feel like I remember my old CBR600RR had. Much less susceptible to wobble. Obviously if I gave it a good jerk it would kinda wobble but much more difficult than before.

[raysigh]

This still begs the question though: Why would my chain adjuster bolts be off by 5mm, and the swing arm tick marks off by about 1.3 lines. 

 

There's so many factors that could affect this, but in my mind it could be:

1. My front wheel alignment wasn't perfect.

2. Something else on my bike is bent (forks, frame?) I KIND of doubt this though as there were no signs of any damage from any drops or falls. He had changed the exhaust, but I got the stock exhaust with it. Otherwise, basically all stock. (so he wasn't changing out parts that may have been damaged in a fall). 

Edited September 21, 2020 by raysigh

[DewMan]

52 minutes ago, raysigh said:

This still begs the question though: Why would my chain adjuster bolts be off by 5mm, and the swing arm tick marks off by about 1.3 lines. 

1.3 lines does seem excessive but the lines on the swing arm are notorious for not being accurate. You'll see numerous threads on the subject.

[raysigh]

2 minutes ago, DewMan said:

1.3 lines does seem excessive but the lines on the swing arm are notorious for not being accurate. You'll see numerous threads on the subject.

Question is... if it passes the string test, and feels ok... should I be worried. My OCD is killing me though. I used to always use distance between the chain adjusting blocks to the end of the bolt, 5mm is a TON.

[DewMan]

4 minutes ago, raysigh said:

Question is... if it passes the string test, and feels ok... should I be worried. My OCD is killing me though. I used to always use distance between the chain adjusting blocks to the end of the bolt, 5mm is a TON.

Check your chain alignment. If the front and rear sprockets are in proper aligninment, I would think you should be fine. 

[raysigh]

21 minutes ago, DewMan said:

Check your chain alignment. If the front and rear sprockets are in proper aligninment, I would think you should be fine. 

Any recommendation for a method to do this without a motion pro chain alignment tool?

My sprocket teeth are sitting to the left of the chain as I spin the rear wheel.

Edited September 21, 2020 by raysigh

[DewMan]

3 minutes ago, raysigh said:

Any recommendation for a method to do this without a motion pro chain alignment tool?

Have you got anything with a straight edge like a yard stick you can sight it along using a small block of something to space it out from the sprocket? to see if it's keeping the same spacing to the edge of the chain from one end to the other?

[raysigh]

8 minutes ago, DewMan said:

Have you got anything with a straight edge like a yard stick you can sight it along using a small block of something to space it out from the sprocket? to see if it's keeping the same spacing to the edge of the chain from one end to the other?

 

So I took a metal ruler, mashed one end against two rivets at the top of the sprocket, and from this .. crude test, it looks aligned? Not sure how accurate this test is though especially if I am myself changing the overall chain resting position by mashing the chain to the left by the pressure I am applying to the right side with the ruler.

[DewMan]

6 minutes ago, raysigh said:

 

 

So I took a metal ruler, mashed one end against two rivets at the top of the sprocket, and from this .. crude test, it looks aligned? Not sure how accurate this test is though especially if I am myself changing the overall chain resting position by mashing the chain to the left by the pressure I am applying to the right side with the ruler.

Turn the ruler 90° so the flat edge that you measure with is against a couple  plates supported by the sprocket and sight along it.

[raysigh]

21 minutes ago, DewMan said:

Turn the ruler 90° so the flat edge that you measure with is against a couple  plates supported by the sprocket and sight along it.

Looks like the rear wheel needs to be adjusted to the right by this test (which would agree with the swingarm markings (and the bolt measurement - 2.5cm left, 2.1cm right). 

That would put me back at square one though, where either my forks are bent, or my front wheel alignment wasn't perfect.

The bike really does feel better, since this did pass the string test - but that means I pretty much just aligned the rear with the front which - it should be the other way around.

 

Question about realigning the front. Because our steering tube pinch bolt is...well a pinch bolt, and not a top screwing bolt, how can we loosen that steering tube letting everything below move freely, without the entire front assembly dropping down? I had just loosened it a bit, but enough to grip (which doesn't really work to allow free movement IMO). 

[DewMan]

2 minutes ago, raysigh said:

 

Looks like the rear wheel needs to be adjusted to the right by this test (which would agree with the swingarm markings (and the bolt measurement - 2.5cm left, 2.1cm right). 

That would put me back at square one though, where either my forks are bent, or my front wheel alignment wasn't perfect.

The bike really does feel better, since this did pass the string test - but that means I pretty much just aligned the rear with the front which - it should be the other way around.

 

Question about realigning the front. Because our steering tube pinch bolt is...well a pinch bolt, and not a top screwing bolt, how can we loosen that steering tube letting everything below move freely, without the entire front assembly dropping down? I had just loosened it a bit, but enough to grip (which doesn't really work to allow free movement IMO). 

I'm guessing you don't have a triple tree pit stand? If not do you have a bean or something overhead to support the front end to keep the frame from sliding down once you loosen the pinch bolts?

I suggest aligning the rear wheel with the front sprocket and then aligning the front wheel to the rear. 
 

If you have a pit stand.. you can always a block of something to support the front wheel to keep the forks from sliding out the bottom of the triple.

[raysigh]

2 minutes ago, DewMan said:

I'm guessing you don't have a triple tree pit stand? If not do you have a bean or something overhead to support the front end to keep the frame from sliding down once you loosen the pinch bolts?

I suggest aligning the rear wheel with the front sprocket and then aligning the front wheel to the rear. 
 

If you have a pit stand.. you can always a block of something to support the front wheel to keep the forks from sliding out the bottom of the triple.

I do have a headlift stand, but I thought to align the front, you need the wheel on the ground just low friction so it can align itself?

[DewMan]

2 minutes ago, raysigh said:

I do have a headlift stand, but I thought to align the front, you need the wheel on the ground just low friction so it can align itself?

us a wood block or something to support the front wheel after you use the stand to support the bike. that'll give you friction you need. 

[raysigh]

4 minutes ago, DewMan said:

us a wood block or something to support the front wheel after you use the stand to support the bike. that'll give you friction you need. ">

I’ll give that a shot tomorrow thanks

[DewMan]

2 minutes ago, raysigh said:

I’ll give that a shot tomorrow thanks

Good Luck

 

[klx678]

Try measuring from your swing arm pivot to the axle on each side, should be equal.   I don't trust swing arm markings, so I measure.  Only way the chain line would be off is if the frame is not right or the swing arm offset somehow.  Highly unlikely.

Edited September 21, 2020 by klx678