Why does my bike suddenly wobble?

[stopintime]

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.....   

[Speeddog]

Tire pressures?

Was the bike sitting on the sidestand while it was in storage?

[stopintime]

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.

[Speeddog]

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?

[OverCaffeinated]

+1
I would say flat spots on tires from sitting too long.

[Spidey]

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. 

[stopintime]

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  

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.

[DLSGAP]

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?

[stopintime]

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

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.

[Speeddog]

+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.

[stopintime]

+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.

[Speeddog]

That rear spring is *really* stiff, IMO.

[stopintime]

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.

[Speeddog]

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?

[flynbulldog]

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