Instability at speed?

[Twisties]

It's happened 3 times now... In a curve at speed... the suspension is set and the chassis is stable. At least two of the times I was accelerating. Then a bump, dip, whoop-dee-doo or such in the road induces a wobble, tank slapper, or pogoing effect. Bike has been loaded at approximately 400 lbs including accessories, me, luggage, etc. So far I have survived.

Is it the Heidenaus K60's? The suspension (lack of damping, incorrect adjustment)? The geometry/suspension... a harmonic?

 

[stevepsd]

Suspension most likely, especially with the load your are carrying. Undersprung and under damped. Check your suspension sag, I bet it's way, way off.

 

[~TABASCO~]

Crank up your suspesion and adjust the compression and rebound, it will help out a ton !!!!!

 

[macca]

K60s!!! they make mine a bit nervous when making progress over road imperfections. I found they are better when pumped up to mid 30's PSI but still not as stable as it was on the oem Tourances

 

[avc8130]

It's happened 3 times now... In a curve at speed... the suspension is set and the chassis is stable. At least two of the times I was accelerating. Then a bump, dip, whoop-dee-doo or such in the road induces a wobble, tank slapper, or pogoing effect. Bike has been loaded at approximately 400 lbs including accessories, me, luggage, etc. So far I have survived.

Is it the Heidenaus K60's? The suspension (lack of damping, incorrect adjustment)? The geometry/suspension... a harmonic?

If you want to ride the bike like that, you NEED this:

http://www.yamahasupertenere.com/index.php?topic=4528.0

ac

 

[Firefight911]

That's classic suspension. I went Ohlin's rear and new springs, fluid, etc. for the front. Made all the difference in the world!!!!!!

Other thing to make sure is you. YOu HAVE to be loose on the bars and be correct with your body positioning to keep the bike from being a bucking bronc from rider inputs.

The combination of these two things are the overwhelming cause of rider complaint on bike handling. Unfortunately, they also carry the most polarizing comments of how it's not the suspension and it's definitely not the rider so it has to be the tires.


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[Don in Lodi]

My Royal Star got unstable when the steering head loosened up.

 

[hANNAbONE]

...tires, with a soft(er) suspension setting, is my guess.

 

[Tremor38]

Re: Re: Instability at speed?

Crank up your suspesion and adjust the compression and rebound, it will help out a ton !!!!!

＋1. I noticed some of what the OP is experiencing after I loaded my side cases last weekened. Increasing the preload helped a ton. I also whole heartedly agree with what Firefighter posted about relaxing your grip on the bars and keeping your arms relaxed..especially when then bike is in a configuration that makes it more proned to oscillations/slappers.

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[avc8130]

That's classic suspension. I went Ohlin's rear and new springs, fluid, etc. for the front. Made all the difference in the world!!!!!!

Other thing to make sure is you. YOu HAVE to be loose on the bars and be correct with your body positioning to keep the bike from being a bucking bronc from rider inputs.

The combination of these two things are the overwhelming cause of rider complaint on bike handling. Unfortunately, they also carry the most polarizing comments of how it's not the suspension and it's definitely not the rider so it has to be the tires.


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2nd!

The rear suspension in stock form is TERRIBLE when the going gets tough. Once that starts happening, the rider loses confidence and the natural reaction is to white knuckle the grips.

You can TRY cranking your preload up to get something close to proper sag. Then most likely ADD rebound damping to try to control the rear. Unfortunately you cannot adjust the compression in the rear.

I have always said it takes "faith" to ride the S10 in stock form FAST on the street. You have to BELIEVE it can make it through the turns and try to relax.

Once you have a REAL aftermarket rear shock (Ohlins/Penske) you won't need faith any more. You'll trail brake into the turn, pitch the bars and rock the throttle open. Complete confidence. No reason to get concerned in the least. Loose grip on the bars. LAUGHING in your helmet. Stupid. Stupid good.

ac

 

[tomatocity]

- You did not mention tire pressure. Inflate them to the maximum of the sidewall rating. You can always lower the pressure.
- Agree with FF911 about gripping the handlebar too tight.
- FF911 set my stock rear shock at full tight -2 clicks. You can always reduce the compression.
- Have you checked your front suspension? If not, check the settings for being equal side to side. FF911 set my stock forks up and they work much better than factory settings.
- Check sag for sure.
- Properly lube and adjust your steering head.
- Make sure your load is balanced side to side and as far forward as possible.

If none of these correct the problem at least you have completed some needed service. Don't forget to check ALL of your nuts & bolts.

 

[avc8130]

Some interesting suggestions there.

I would start with air pressure at the factory suggested settings. Air pressure required is a function of load.

You CANNOT reduce the "compression" on the rear shock. It simply isn't adjustable on the stock shock.

Did you know...some bikes have 1 fork leg that controls rebound and the other controls compression? Identical settings side to side are not required...but of course that would be desired. It is tough to suggest what adjustments to make over the internet. Definitely at least baseline with the suggestions in the manual. If tomatocity wants to share his settings, you could try them.

With regards to positioning your load...you should adjust your sag AFTER loaded. This will make sure front/rear load and geometry are balanced/maintained.

I FIRMLY believe what the OP is experiencing is the affect of the under-damped rear shock. At loads as he describes (400 lbs) he is just flat out beyond what the stock shock can control.

I am going to assume he has the preload set to max "hard/stiff" as the manual calls it (this is so wrong it isn't funny). IF that is the case, I would try increasing rebound damping (bottom of the shock, turn to "hard/stiff") until the issue gets better. Always go at least 2 clicks. That way, as you approach "good" you always have the option to go back one. You need to go 2 so you get a difference big enough to feel. I have a feeling you will be very close to "max" before you are "satisfied". I would be very surprised if the OP can attain "happy".

ac

 

[Tremor38]

Some interesting suggestions there.

I would start with air pressure at the factory suggested settings. Air pressure required is a function of load.

You CANNOT reduce the "compression" on the rear shock. It simply isn't adjustable on the stock shock.

Did you know...some bikes have 1 fork leg that controls rebound and the other controls compression? Identical settings side to side are not required...but of course that would be desired. It is tough to suggest what adjustments to make over the internet. Definitely at least baseline with the suggestions in the manual. If tomatocity wants to share his settings, you could try them.

With regards to positioning your load...you should adjust your sag AFTER loaded. This will make sure front/rear load and geometry are balanced/maintained.

I FIRMLY believe what the OP is experiencing is the affect of the under-damped rear shock. At loads as he describes (400 lbs) he is just flat out beyond what the stock shock can control.

I am going to assume he has the preload set to max "hard/stiff" as the manual calls it (this is so wrong it isn't funny). IF that is the case, I would try increasing rebound damping (bottom of the shock, turn to "hard/stiff") until the issue gets better. Always go at least 2 clicks. That way, as you approach "good" you always have the option to go back one. You need to go 2 so you get a difference big enough to feel. I have a feeling you will be very close to "max" before you are "satisfied". I would be very surprised if the OP can attain "happy".

ac

For sure there are some big boys who ride this bike. Myself + wife + luggage would be probably be about 375lbs. Everytime I hear you rag on the stock suspension, I get the urge to check your exaggerations, but then I remember what I wrote earlier...there are some big boys that ride this bike. I will have to say that I've owned bikes that had much worse factory suspension than this though. Maybe if I weighed 200+lbs I would be using such seemingly hyperbolic adjectives as 'hot mess' and 'terrible/horrible' etc I dunno..as I said, I've experienced much worse.

 

[mcbrien]

[.







I am going to assume he has the preload set to max "hard/stiff" as the manual calls it (this is so wrong it isn't funny).

ac

What does this mean ?
I weigh 190+ and had to set rear shock to nearly full hard and preload on front forks to full
soft to even come close to get proper sag ?



[/quote]

 

[avc8130]

[.







I am going to assume he has the preload set to max "hard/stiff" as the manual calls it (this is so wrong it isn't funny).

ac

What does this mean ?
I weigh 190+ and had to set rear shock to nearly full hard and preload on front forks to full
soft to even come close to get proper sag ?

I find it funny that the manual refers to preload settings as "hard" and "soft". The spring rate CANNOT change with preload setting. Really the actual "setting" doesn't matter. What matters is getting the numbers and geometry correct. Shoot for ~55mm front and rear rider sag. Then check the static sag. That will let you know how close the stock spring rates are for you.

On the front it is a bit different with the 2-rate springs. The concept remains the same, but the performance will have 2 distinct feelings depending on where in the travel you are.

ac

 

[avc8130]

For sure there are some big boys who ride this bike. Myself + wife + luggage would be probably be about 375lbs. Everytime I hear you rag on the stock suspension, I get the urge to check your exaggerations, but then I remember what I wrote earlier...there are some big boys that ride this bike. I will have to say that I've owned bikes that had much worse factory suspension than this though. Maybe if I weighed 200+lbs I would be using such seemingly hyperbolic adjectives as 'hot mess' and 'terrible/horrible' etc I dunno..as I said, I've experienced much worse.

It all depends HOW you ride the bike.

I experienced the exact same nuances the OP did. The bike would be "decent" untill I pushed it. Then any bump in the corner would make the rear a hot mess. Once the rear started bouncing there was no settling. I tried adjusting the rebound, but without the ability to dial in the compression I couldn't take control. Stiff rebound damping resulted in a slightly more controlled ride, but then the shock was subject to packing over washboards. The stock spring was actually CLOSE in rate for me, but I was unable to get enough preload on it with the stock hydraulic adjuster. I wound up with the forks raised 10mm in the triples to maintain a geometry that steered neutral.

Adding my wife made it very scary. The geometry went to heck pretty quickly as we were unable to get proper front wheel loading since rear sag was so high.

I agree I have owned bikes with worse suspension than this. My SV650 comes to mind. However, that bike was ~$8k...not ~$14.5k. My ~$13k Buells had EXCELLENT factory suspensions. Just because "worse" exists doesn't mean we have to settle for what we have.

I still mainain, the aftermarket suspension has been the absolute best farkle for my S10 to date. The hyperbolic adjectives only started coming out once I EXPERIENCED the aftermarket suspension. The level of composure and confidence the aftermarket suspension provides is impossible to relay effectively.

The best you know is the best you've ridden.

ac

 

[Firefight911]

Well said AC!


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[Twisties]

Just to respond, first, thanks for the suggestions. Second glad to hear I am not the only one.

I have the rear preload set to maxmium ("Hard") and the rear rebound damping set to maximum as well. The first time it happened rebound was not set properly. Now the bike is typically fine, until it just breaks loose.... a hot mess, as was said. Yep, stay loose on the bars... for sure... I also chopped the throttle until it settled, FBOW. Tires are set to 36 psi front and rear. 36 is the max inflation for the K60's.

Whoever said it affects your confidence on the bike it right.

I guess what I found different about this is that other bikes I have had just got sloppy when the suspension was out of whack. They didn't act all fine and dandy for days and then suddenly turn whacko...

I will check the static sag, but the bike is not bottoming out or topping out, so I think the sag is somewhat reasonable. Most likely inadequate damping.

 

[pluric]

It's happened 3 times now... In a curve at speed... the suspension is set and the chassis is stable. At least two of the times I was accelerating. Then a bump, dip, whoop-dee-doo or such in the road induces a wobble, tank slapper, or pogoing effect. Bike has been loaded at approximately 400 lbs including accessories, me, luggage, etc. So far I have survived.

Is it the Heidenaus K60's? The suspension (lack of damping, incorrect adjustment)? The geometry/suspension... a harmonic?

The first time I had my new K60s at speed it scared me bad. Front end felt floaty, very little stability at the triple digit range.
The stock tires never did that. I was loaded for a trip. I was quite surprised at how different the bike felt. It did get better with
miles. Never has felt as stable as it did with the stock tires. I'm staying with the K60s because they sure wear well.

 

[avc8130]

Just to respond, first, thanks for the suggestions. Second glad to hear I am not the only one.

I have the rear preload set to maxmium ("Hard") and the rear rebound damping set to maximum as well. The first time it happened rebound was not set properly. Now the bike is typically fine, until it just breaks loose.... a hot mess, as was said. Yep, stay loose on the bars... for sure... I also chopped the throttle until it settled, FBOW. Tires are set to 36 psi front and rear. 36 is the max inflation for the K60's.

Whoever said it affects your confidence on the bike it right.

I guess what I found different about this is that other bikes I have had just got sloppy when the suspension was out of whack. They didn't act all fine and dandy for days and then suddenly turn whacko...

I will check the static sag, but the bike is not bottoming out or topping out, so I think the sag is somewhat reasonable. Most likely inadequate damping.

Check your sag, both rider and static front and rear. Report back the numbers.

I have no experience with the K60s, but I have experienced what you described with the stock B-Wings. Faith. I never had an "issue", but there certainly was a lack of confidence.

I am not sure what FBOW means, but chopping the throttle generally doesn't help the situation. When you do that you instantly unload the rear tire and this is generally a bad thing. Smooth on the throttle. The stock suspension needs all the help it can get to be smooth. You whacking/chopping on the throttle doesn't help it.

Slow is smooth, smooth is fast.

ac