Took my bike back home from storage today and was surprised by a slight wobble at 110mph - so far only detected turning left
at a few very wide turns.
During winter I've gotten new suspension. The rear is a bit higher due to a much stiffer linear spring and the front is lowered about 5mm to make room for the SpeedyMoto top triple. I now have clip ons which lowered the grips about two inches from stock.
My tires are the same as last year.
The same turns could be taken at 130 last year, rock steady then.
I will discuss this with my suspension guru, but I would like your ideas first..... [thumbsup]
Tire pressures?
Was the bike sitting on the sidestand while it was in storage?
Quote from: Speeddog on April 07, 2009, 08:28:54 AM
Tire pressures?
Was the bike sitting on the sidestand while it was in storage?
I haven't checked the pressure, but my dealer told me that part of the preparation out of storage was to check it. They recommend f/r 36/38.
Not sure if they in fact did it. It was chilly today, 45F. I had been riding for an hour or so.
I'm guessing, but probably on the side stand since mid January.
FORGOT TO MENTION: new chain and sprockets too.
Just a suspicion, but the tires, and specifically the front, may have gotten a bit of a flat spot from sitting.
The flat spots should go away in a bit of time.
No FHE on this causing an issue, just seems connected due to the behavior in left turns...
I forgot, what springs do you have now?
+1
I would say flat spots on tires from sitting too long.
1) You raised the rear and lowered the front and now you're getting some wobble? Not surprising. At all. Talk to your suspension guy.
2) New chain and sprockets? Confirm rear wheel alignment is straight.
3) Also check your steering head nut is tight. I don't know why that would affect only left hand turns, but check it anyway.
4) Check your wheel weights are all still there. Again, it wouldn't affect just left hand turns, but check anyway.
5) Are your brakes rubbing on one side or another?
6) Front axle properly torqued?
7) Fork heights the same?
BTW, 36/38 seem pretty high.
Flat spots would appear on the left side of the tires - causing only left turn wobble. That's what you're saying, right?
This could make sense, since there is nothing straight forward and as far as I know nothing turning right. Checking this further will mean continuously doing 110-120 turns - nice excuse [leo]
If I got the conversion right, it's 9.3 front and 857 rear. Does that make any sense? (Besides the fact that the rear is unusually stiff)
SpeedDog - are you thinking that the front is too soft compared to the rear? The guru shop will redo the whole thing if I'm not happy with the way things work out - a continuing wobble situation would certainly be such an occasion.
you should be able to check for flat spots by putting it up on a rear stand and just manually rotating the tire while visually inspecting the left side or running one hand on it as you turn it with the other... if its enough to cause a wobble you'll be able to feel it. those pressures do seem pretty high. what kind of tires are you running?
Quote from: Spidey on April 07, 2009, 08:59:04 AM
1) You raised the rear and lowered the front and now you're getting some wobble? Not surprising. At all. Talk to your suspension guy.
2) New chain and sprockets? Confirm rear wheel alignment is straight.
3) Also check your steering head nut is tight. I don't know why that would affect only left hand turns, but check it anyway.
4) Check your wheel weights are all still there. Again, it wouldn't affect just left hand turns, but check anyway.
5) Are your brakes rubbing on one side or another?
6) Front axle properly torqued?
7) Fork heights the same?
BTW, 36/38 seem pretty high.
I will keep all of these in mind - good to have them all checked out anyway [thumbsup]
Quote from: DLSGAP on April 07, 2009, 09:06:06 AM
you should be able to check for flat spots by putting it up on a rear stand and just manually rotating the tire while visually inspecting the left side or running one hand on it as you turn it with the other... if its enough to cause a wobble you'll be able to feel it. those pressures do seem pretty high. what kind of tires are you running?
I have Metzeler Sportech M3.
+1 on checking Spidey's suggestions.
So the springs are .93 kg/mm front and 853 lb/in rear?
Yes, flats spots would be left of center on the tires, so it's possible that could be it.
+2 (?) on those pressures being a bit high.
Although, if you've run those pressures in those tires before without an issue, it may not be relevant to the situation.
Quote from: Speeddog on April 07, 2009, 09:13:29 AM
+1 on checking Spidey's suggestions.
So the springs are .93 kg/mm front and 853 lb/in rear?
Yes, flats spots would be left of center on the tires, so it's possible that could be it.
+2 (?) on those pressures being a bit high.
Although, if you've run those pressures in those tires before without an issue, it may not be relevant to the situation.
The numbers I got was 9.3N forks and 150N rear. Both linear. The brand is WP.
That rear spring is *really* stiff, IMO.
Quote from: Speeddog on April 07, 2009, 09:37:20 AM
That rear spring is *really* stiff, IMO.
I know, you brought it up when I asked for comments on my new suspension in January. As I understand it your know how is professional, so I asked my guru what he thought about your recommendations (650ish vs 850?). Of course he was sceptical (forum advice issues) - I told him to be open minded as yours was advice from a fellow professional - he said the different opinions was due to very rough road conditions, number of track days and my disregard for comfort. Still too stiff? What my mind can't understand is why the difference between your advice and his, doesn't also show itself at the fork spring rates. I will try to have some of the track experts in my local club test my bike to give me an impression of the balance between the front and rear.
From my ride today, only one this season, I'm not able to tell if any of the handling is at it's optimum.
I've resprung a few bikes for guys weighing 215-260#, with 11.6 and 12.5 (650 & 700 lb/in) rear springs.
No complaints back from them, and they know my phone number. ;)
But, SoCal roads are not your roads.
My customers are not you.
I respect that your tuner will have local knowledge of the roads you ride, and likely has talked at good length with you about what you want.
It is a concern when a suspension change results in an instability.
This wobble you experienced, was it a slow weave of the whole bike?
Or was it a faster wiggle, mostly in the bars?
This is not a tire problem -
You changed the geometry of the bike. By adding clip-ons, raising the rear, and lowering the front You increased the steering quickness and with that comes instability.
Every adjustment is a trade off - normally monsters respond well to raising the rear but I think in your case you went too far, you need to get your weight off the front end and get the front back up to stock.
Put you stock bars back on and raise the tripples back up and I'd bet money that your problem goes away.
The monster is so good at what it does its a shame to loose that by trying to make it into something it isn't, I guess for me personally I wouldn't put risers on my 1098 or clip-ons on my monster I think it sort of defeats the purpose of the two different bikes
dude after you made your monster a superbike did you add a steering damper?
I'm assuming you put the clip-ons above the triple? You could try putting them below the trip where they belong and raise the trips back up to stock. That may be enough to do the trick ???
Quote from: Speeddog on April 07, 2009, 12:39:25 PM
I've resprung a few bikes for guys weighing 215-260#, with 11.6 and 12.5 (650 & 700 lb/in) rear springs.
No complaints back from them, and they know my phone number. ;)
But, SoCal roads are not your roads.
My customers are not you.
I respect that your tuner will have local knowledge of the roads you ride, and likely has talked at good length with you about what you want.
It is a concern when a suspension change results in an instability.
This wobble you experienced, was it a slow weave of the whole bike?
Or was it a faster wiggle, mostly in the bars?
Time will tell if my guy has managed to make my bike as good as it can be for the money - and for me.
Can you tell from the new rates how they relate to stock - I mean, did my guy stiffen up the rear more than the front (percentages)?
How fast is "fast"? It was much slower than for example the vibration you would get from an unbalanced car tire.
At first I thought it was because I was on the small lines/dots dividing lanes - the frequency could be similar, +/- 5 per second?
It wasn't strong enough to move the bike around - I really couldn't say if I felt it through the bars or the seat/tank.
BTW: the rear is now almost an inch higher than stock at free sag (12mm) - riders sag 36mm
Quote from: Raux on April 07, 2009, 03:27:24 PM
dude after you made your monster a superbike did you add a steering damper?
Nope - I'll have to wait to know if the bike has become generally unstable or if it's something that can be done to
correct a mistake or careless work (like on Spidey's list). If it's a thing from his list, a damper would just cover up, not solve, a problem.
Your previous comment is backwards, isn't it? "Superbiking" me over the tank will add weight to the front, making the front more stable??
I know that an inch at the rear and lowered front (just 5mm or so) will make the bike more twitchy, but other than the wobble it felt very stable and far from too "easy".
My clip ons are mounted below the triple and have 3.5" risers on them - still the grips are two inches lower than stock.
It's the SpeedyMoto top triple that required the front to be lowered.
One of the intriguing parts of the puzzle is still why the wobble apparently only occurred in left turns.
one thing to look at is rider input. with the new clipons you may possibly be stiffarming on lefts (but not rights where your arm is bent more due to twisting the throttle). this can cause a weave. can you take your left hand off the bars once turned in? (please check that carefully).
Quote from: Statler on April 07, 2009, 04:15:16 PM
one thing to look at is rider input. with the new clipons you may possibly be stiffarming on lefts (but not rights where your arm is bent more due to twisting the throttle). this can cause a weave. can you take your left hand off the bars once turned in? (please check that carefully).
I'll even try both arms and legs, if you think it would help ;D
In fact I checked my arms regularly, most of the time I noticed better leg/core work and loose elbows - which was one of my goals with the clip ons mod.
I'm not 100% sure if that was maintained when the wobbles happened. I was tucked in at the time and couldn't have had straight arms, but going that fast I might have had stiff arms.
Tell me more about the "one hand off the bar" exercise - sounds educational....
sorry...wouldn't take my hand off the bar on a weaving bike.....just making sure you're not tightening up and transmitting more wobble. I was stunned at the end of my fourth track course when I was raising my left hand to signal I was slowing and pitting in while still cranked over with my knee on the ground. There were some areas on the track the bike felt unstable and it turns out it was me getting tense and gripping the bars hard....the bike's natural little corrections were being screwed up by me. I relaxed and the front moved a little but the bike overall was like a rock after that. (also s4rs with clipons and its ass in the air a bit...and BSTs..and steering damper which can't fix my input weave)
I like all the other suggestions here more.....just a thought in case nothing else pans out.
QuoteSuperbiking" me over the tank will add weight to the front, making the front more stable??
No - Wrong - You loose stability, you gain front traction and you gain steering quickness both at the cost of stability.
You've gone too far. I was just at a race suspension seminar, many of the riders raise the rear a little at a time untill the bike becomes unstable ( like yours)
Then they lower it back down till it settles in. Your scenario is very typical but if you want to chase geese feel free [bang]
Remember to change things in small increments, one at a time. I agree this is a geometry issue.
You say it's only in the left at that speed, is there an identical corner going right, with the same imperfections and bumps?
hmm raised an inch in the back.. that does seem high...
ducs are so finicky.. lol
Just to clarify...
He didn't raise the rear, per se.
It's been resprung, so it's more the case of the rear end being back to where it should be.
Quote from: Speeddog on April 08, 2009, 08:27:35 AM
Just to clarify...
He didn't raise the rear, per se.
It's been resprung, so it's more the case of the rear end being back to where it should be.
And According to the OP resulting in +1inch - so it is the chicken or the egg.
mitt
Quote from: mitt on April 08, 2009, 09:07:12 AM
And According to the OP resulting in +1inch - so it is the chicken or the egg.
mitt
Not a chicken, not an egg - I ride at the rear height the Monster is meant to be, and it's just a "little" lower up front. It's different from before, but before was too low. The geometry is not very different from that of many/most Monsters.
Quote from: Roscoe on April 08, 2009, 08:06:07 AM
Remember to change things in small increments, one at a time. I agree this is a geometry issue.
You say it's only in the left at that speed, is there an identical corner going right, with the same imperfections and bumps?
I will have to wait for a suitable opportunity to check if I experience any right hand wobbles. If I do, it might narrow the possible scenarios.
Quote from: stopintime on April 08, 2009, 11:38:26 AM
Not a chicken, not an egg - I ride at the rear height the Monster is meant to be, and it's just a "little" lower up front. It's different from before, but before was too low. The geometry is not very different from that of many/most Monsters.
I will have to wait for a suitable opportunity to check if I experience any right hand wobbles. If I do, it might narrow the possible scenarios.
Sounds like you have the bases covered from all the good input.
I have no FHE with your swingarm type, but is it possible that with the gear/chain swap you ended up with less swingarm length (shorter wheelbase) and/or more rear ride height than you expected?
I think you indicated 36mm rear rider sag. What is your front free/rider sag? Your static geometry might not be so different than most monsters out there, but with such a heavy rear spring you might not be loading it up much in a gentle sweeper, so the attitude of the bike through the turn could remain too aggressive. Just speculating out loud here.
BK
5 mm drop is *very* aggressive.
I took mine down 2 mm, and anymore was totally unstable. Without raising the rear.
Quote from: TiAvenger on April 08, 2009, 01:40:04 PM
5 mm drop is *very* aggressive.
I took mine down 2 mm, and anymore was totally unstable. Without raising the rear.
I guess it depends on what you like or what you are used to.
My hoop style Monster is raised as far as possible with the heim joints.
I weigh about 175-180 in street clothes and run a 10.0 rear spring
There is 25 mm of fork tubes sticking above the top triple.and I have .85 springs and racetech valves with a modified stack
The thing turns like a 250
and is stable in turns and in a straight line at speed.
Can I say that someone else would like it...I know some do.
YMMV.
I'm with Statler on the rider input theory...
as soon as the OP checks his steering head bearings.
Quote from: BK_856er on April 08, 2009, 12:40:16 PM
Sounds like you have the bases covered from all the good input.
I have no FHE with your swingarm type, but is it possible that with the gear/chain swap you ended up with less swingarm length (shorter wheelbase) and/or more rear ride height than you expected?
I think you indicated 36mm rear rider sag. What is your front free/rider sag? Your static geometry might not be so different than most monsters out there, but with such a heavy rear spring you might not be loading it up much in a gentle sweeper, so the attitude of the bike through the turn could remain too aggressive. Just speculating out loud here.
BK
Good points - there is some height differences through a chain life - it changes a little for each adjustment. I don't know where it is at the moment though.
The rear of my bike would certainly sink in much more through a turn than it's doing now.
Quote from: TiAvenger on April 08, 2009, 01:40:04 PM
5 mm drop is *very* aggressive.
I took mine down 2 mm, and anymore was totally unstable. Without raising the rear.
Some people say "won't notice" - others say "very aggressive" about a 5mm drop. The only thing I know is that other than the high speed wobble, my bike felt very stable and not at all twitchy.
Thanks for all the input guys - keep it coming. I didn't spend all that cash without expecting everything to work well. I WILL make it work as planned [thumbsup]
Quote from: ducpainter on April 08, 2009, 02:22:20 PM
..........................................
I'm with Statler on the rider input theory...
as soon as the OP checks his steering head bearings.
Yeah - blame the noob [bang] ;) Actually, at least in theory, it's more likely that I did something wrong than the shop guys - they probably know their stuff - I don't.
How can I check steering head bearings? I got a new DP steering head bling nut. Wouldn't you expect the shop to to check the bearings while changing the nut?
Quote from: stopintime on April 08, 2009, 02:50:31 PM
Yeah - blame the noob [bang] ;) Actually, at least in theory, it's more likely that I did something wrong than the shop guys - they probably know their stuff - I don't.
How can I check steering head bearings? I got a new DP steering head bling nut. Wouldn't you expect the shop to to check the bearings while changing the nut?
I'd expect that they checked it as part of a suspension rebuild/set-up.
The guy that does my work checks them every time he gets his hands on the bike.
It's common for the wear or detenting (the technical term is brinelling from shock loads while not rotating) to occur right at the center.
I had a vicious wobble develop on my bike. The bearings had a wear spot very near center. You'd enter a high speed turn and the steering would need a little more so you adjust and because it took more effort to get past the detent I'd over correct...then correct again...and again...and again...each time in the opposite direction. At 100 mph that translates into some serious pucker factor.
It wouldn't hurt to ask them if they checked. It's not hard to do your self.
Quote from: stopintime on April 08, 2009, 02:50:31 PM
How can I check steering head bearings? I got a new DP steering head bling nut. Wouldn't you expect the shop to to check the bearings while changing the nut?
Suspend the front (I used an A-frame ladder and tie-downs to the bike frame) and shake the forks front/back. Clunking or clicking indicates excessive head bearing slop. Also check for smoothness of operation. With the bike on the ground it would be a good idea to loosen and then torque the special nut to spec to remove all doubt, but that requires a special tool and suitable torque wrench. The first check is easy and will alert you to any gross issues.
BK
I need to fire up the geometry squad here.....
(Think I know how)
The front is probably lowered as much as 10mm :o
The stock triple is "curved" - it falls down from the steering head area towards the fork pinch part - by about 10mm. The SpeedyMoto triple is flat.
Comparing the two will show a difference of about 10mm.
But I still think my bike felt stable to ride ;)
Bit of a long shot, but I'm wondering whether your rebound damping might not be coping with the much stiffer rear spring. I imagine your guru must have revalved the shock, but valving or adjustment might not be quite right first-up.
It is possible (if again a long shot) that the problem appears only in left turns because only those few high-speed lefts where you've tried it have the sort of bumps that upset the suspension.
A little bit of oscillation at the rear can easily feed into the front through rider and handlebars.
Quote from: Moronic on April 08, 2009, 06:26:05 PM
It is possible (if again a long shot) that the problem appears only in left turns because only those few high-speed lefts where you've tried it have the sort of bumps that upset the suspension.
This is what I was wondering. Maybe find some right handers that might induce the wobble. Remove one piece to the puzzle at a time.
I went for short and not so fast ride today - very conscious about what was going on.....
First, the bike is very stable on the highway, but it's obvious that it steers much quicker now - much more sensitive. I was cruising through a village, kind of upright with almost straight arms - hit a small pothole that surely wouldn't have upset the bike before, but today it did. I went back, leaned forward and relaxed my grip - ran into the same pothole and had no reaction (other than the compression).
I found that I do the thing with the left arm straighter than the right (Statler's advice). I really have to work to get into the forward position / clip on / loose grip thing - I thought I was being ok with that, but there's some work that needs to be done before it gets all natural.
I'm very close to accepting the changed geometry + faulty rider input as the main reasons for the wobble, but I will check everything to have the best understanding and to make sure everything is working to my advantage.
Talk to you soon [thumbsup]
Good that you're getting it sorted. [beer]
So the problem was the nut that holds the handle bars then. ;D
Quote from: silentbob on April 09, 2009, 09:57:00 PM
So the problem was the nut that holds the handle bars then. ;D
"it's hard to be humble when you're as great as I am" :D
Quote from: stopintime on April 09, 2009, 11:19:29 PM
"it's hard to be humble when you're as great as I am" :D
I think there's song with the lyric, "Lord it's hard to humble when you're perfect in every way!"
Glad to hear that you're adjusting to your new riding position. [moto] It'll take a bit, especially since I think you've mentioned that you're well over 6 feet tall.
Guys, just a little update after the first 600 miles.....
I had the suspension shop go through the list of suggestions today - including the "too stiff rear spring" issue.
The changes are quite radical and they are new to me, but I'm starting to understand what is happening and what I need to do.
I need to be very aware and to work hard on my technique. Before the changes I could get away with a lot of lazy attitude - now I get a clear message from my bike every time I forget to watch my rider input, forget to look through turns, forget to position my body properly a.s.o.
If I follow Lee Parks' book and everything I learned from DML/DMF it works great. If I don't, the bike tells me to sharpen my actions.
I wanted to take my skills to the next level and that's what's happening now.
The first track day is only a couple of weeks from now - I guess I'll know a lot more then.
If I decide to back up a bit - my options are: lowering the rear, adjusting the rear suspension (preload/rebound), add a steering damper, play more with tire pressure - anything missing?
Thanks again for helping me understand what this riding thing is all about - your help is valuable and inspiring [thumbsup]
Even if you have the suspension well sorted, a Monster, especially one driven an enthusiastic person, with the ride height adjusted the way yours is, needs a good steering damper. I put an Ohlins on mine and it made a noticeable difference, especially when cranked over on bumpy pavement.
Over the years I found that very light on the controls is paramount too.
Mines down about 8mm in the front and up 25mm in the rear too.
LA
Quote from: LA on April 26, 2009, 05:28:04 PM
Even if you have the suspension well sorted, a Monster, especially one driven an enthusiastic person, with the ride height adjusted the way yours is, needs a good steering damper. I put an Ohlins on mine and it made a noticeable difference, especially when cranked over on bumpy pavement.
Over the years I found that very light on the controls is paramount too.
Mines down about 8mm in the front and up 25mm in the rear too.
LA
Not everyone feels the need for a damper on a raised ride height monster.
I won't say you shouldn't if you don't say I should. ;)
Quote from: ducpainter on April 26, 2009, 06:01:19 PM
Not everyone feels the need for a damper on a raised ride height monster.
I won't say you shouldn't if you don't say I should. ;)
But.....you're old and used to wobbly. ;D
Quote from: trouble on April 26, 2009, 06:38:47 PM
But.....you're old and used to wobbly. ;D
just like you're used to slow.... [evil]
;)
[laugh]
Quote from: ducpainter on April 08, 2009, 02:22:20 PM
I guess it depends on what you like or what you are used to.
My hoop style Monster is raised as far as possible with the heim joints.
Same here, no adverse effects. Also, to whoever put that putting clipons on a Monster changed the bike, blah blah blah. that's neither here nor there, and doesn't alter the suspension geometry unless the installation moved the forks up or down in the triples (which isn't necessary but is sometimes done on request or mistakenly thought it was needed).
I've got my rear jacked up, top end rear shock put on, clipons, forks revalved and resprung and its still a Monster, not a superbike. It steers quicker, sure, but its far from a SBK. I've put a steering damper on awhile back as insurance, and I like the feel, but wasn't compelled to do so because the bike 'needed it'. The OP and several others have done the same thing. Folks that cry foul when somebody changes their bike should log-off the computer and go sit in the comfort of their own garage where no other opinions will interfere with their belief about how the world should work. [roll]