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Breva 1100 with skittish steering

KerryBlue

KerryBlue

Just got it firing!
Joined
Jun 12, 2010
Messages
21
Location
Lismore, Co. Waterford, Ireland.
Don't know if ''skittish'' is a technical term but it describes the way my front wheel is behaving recently.
It's not too bad on good roads - it feels very light and unplanted, but on bad road surfaces it seem to have a mind of it's own. After a 150 mile run yesterday it was particularly bad - it almost felt unsafe.
I've searched here and other forums but none of the usual causes for this sort of behaviour seem to apply.
Tire pressure, which I checked after yesterday's run [ when the tires had cooled down], was within 0.5 psi of the recommended pressure. The tires themselves, Dunlop Roadsmarts, have less than 3,000 miles. My last set of Roadsmarts were behaving perfectly after more than 6,000 miles.
Steering head bearings were replaced about 12,000 miles ago and appear to be fine - no play or notching.
Fork oil was changed at the same time.
I've changed nothing on either front or rear suspension.
My riding style hasn't changed in the last few weeks. I've tried holding the bars tightly and very lightly but it makes no difference. The bike has done just over 25,000 miles.
I can't think of anything else.
Any ideas?
 
Front wheel bearings?
By "skittish" do you mean the handlebars shake back and forth violently?
At times a front end shake, wobble or oscillation can be caused entirely by a rear end problem.
Rear tyre pressure? Swingarm bearings? Shock oil gone off? Internal shim stack breakage?
All the suspension linkage bearings would be dry if they haven't been re-greased since new. They could be seized or just very sloppy.
 
Front wheel bearings seem fine.
No violent shaking of bars. It's just that the front wheel seems to want to follow any imperfections in the road surface. The whole front of the bike seems be to lighter than before and less stable.
It reminds me a bit of the way the bike behaved when I had well worn BT 23s on it.
As I said, it has always been very stable and solid with the Roadsmarts.
 
Front can often be rear bearing related as ghezzi hints to. There's no shim stacks in the B11 forks.

On rare occasion, you can get a faulty tire. I've seen it a handful of times. Perhaps have a critical eye put on it for round-ness, balance, etc.
 
You may also want to check the tire pressures with a second, known correct, gauge. I have seen gauges take a hit and start reading wrong. Too high air pressure can make a bike feel nervous. Make sure when you check the wheel bearings you check rear as well as front. There are only so many things that could cause this sort of behavior, be methodical and go through the bike.
 
B11 is CARC, = no rear wheel bearings, hate to think what would have happened if the diff bearings were that worn to cause the wheel to wobble. Check wheel nuts torque.

While Todd said no shim stack in the forks, I presume the rear shock has a shim stack, I've seen shims snap before and this then causes a deteriation in the ride quality.

But as you alluded to similar experiences before with worn tyres, I suggest you look at them very closely. Even if you can't find fault buy a new pair and try them. Its better to be safe than sorry.

I've been at a mate for 12 months to fix the suspension on his SC1000 Ducati as it tank slaps on bumpy straight roads. Too late! He totalled the bike on the weekend after being spat off at 120kph.
 
I have an '06 B11. I had similar sounding issues a few years ago. I set my tyre pressures at 38 & 40, and wound up my rear preload and rebound to match the manual for two up riding with luggage. For me the problem went away.

I'm not an overly fast rider and back then I had Pilot Road 2's.

cheers

Robert
 
Ah ha! Just came to mind. Was told recently that supposedly the same tyre, at least to eye and by name can be totally different.

Why would they make a 180/55 or 120/70 tyre exactly the same for small light bike as well as a fat heavy bike. They don't. Often a bike manufacturer will request a special construction of a tyre, to suit an individual model.

ie. For a light 600cc sports bike the tyre can be made softer in the sidewall with a thinner overall carcass and therefore a tyre which is lighter in weight. That same tyre on a 225kg bike may have excessive sidewall flex, unless inflated to higher than normal pressures.

How do we tell the difference?
Any tyre guru care to chime in?
 
My money is on the tyres.

Ghezzi mentions the different weights, I've seen this on Continental tyres for tourers, they have a heavier tyre for 2 up loaded with luggage, there is an identifier in the size / rating marks on the side wall. I don't think the roadsmarts are available in this option, but best check their web site with what is on your side wall.

Check that the pressure is correct on dunlop's web site for the type of tyre on your bike, not what's recommended in the Guzzi book, they will differ.
 
KerryBlue. I had the same symptoms, found if I reduced the tyre pressures to 34/36 and reduced the compression
damping to lowest setting it handles a lot better.
 
Thanks for the comments so far guys.

I've just had a look at the Dunlop website. They actually recommend Sportmax Roadsmarts for the Breva 1100, which is what I have on my bike - recommended size as well. Their recommended pressure front and back is the same as the Guzzi recommendation.
I've also checked my pressures with a second guage just to be sure, and my pressure is fine.

So, it's not a tire choice problem or a pressure problem.
The front tire looks ok as far as I can see - but of course that doesn't mean there isn't a problem there.
I'm a bit reluctant to replace tires which have done less than 3,000 miles on the off chance that this is where the problem lies. Of course if I have to I will.

Any other ideas?
 
Try with more and less air in the tyres just to eliminate the theory. I have a higher psi than is recommended. Don't forget your body weight along with other factors may not be the same as was tested when the tyres are designed.

Robert
 
As suggested earlier, a problem at the front can be caused by a component at the back. Place the bike on the center stand, or get it supported in a similar manner with the rear wheel off the ground. Check for side to side play by pushing and pulling on the back end of the rear wheel to check for lateral play. If there is play, then start looking for the culprit. It could be swing arm bearings, shock linkage and hopefully not the CARC bearings.
 
I'm a bit reluctant to replace tires which have done less than 3,000 miles on the off chance that this is where the problem lies. Of course if I have to I will.

Don't throw the old tyres away, just try brand new tyres and see if there is a difference in handling.

A. Check the manufacture date of the tyres, make sure your new tyres are very recent and not from the same batch.
There have been instances before of bad batches of tyres, they will never advertise that fact.

I've seen exploding Metzelers, bulging Bridgestones, deformed Dunlops etc. Man made products aren't guaranteed to be perfect, everytime. They all have a percentage of products that fail prematurely.
 
Best thing you can do with a CARC bike is check every bearing and bush. They assemble the buggers dry. My handling woes started at 32,000km with a dodgy feeling front end. Steering head bearings were dry and rusty! The rear shock linkages go dry quickly too. I replaced the head bearings, stripped and greased the shock and swing arm pivots, new fork oil and the thing handles sweet as! Now done 37,000kms and love it.
 
Well, I've checked the rear wheel for play - everything is fine there. Also took the rear suspension linkages apart. The bearings actually had grease! I must be one of the lucky ones. I packed in a bit extra anyway.
But I think I may have found the problem. Or at least the guy who runs a local Honda dealership did. He's a Guzzi fan and did some work on mine when I first got it. I was passing so I dropped in and asked him to take a look. After a spin, he reckons that there actually is a problem with the steering head bearings. They seemed perfect when I checked them but he said he could feel some notching at low speed.
So I have new bearings on order.
If that doesen't work, I'll fit new tires.
Thanks for all the advice - I'll let you know how I get on.
Tom.
 
Have you tried checking the front suspension settings? I have tried playing around with pre-load, oil weight and quantity. Some of the results were on the scary side of interesting! Set the front forks as the book and see if that helps. It has got to be cheaper than tyres.
 
Everything's back to normal! :D
It turned out that the head bearings were knackered after all.
Still can't understand it - they were changed 14,000 miles ago with tapered bearings. Totally rusted up. The bike is kept in a shed. I never power wash it and generally don't ride in the rain. Except, that is, for a week last June when I took it to Scotland. It p***sed rain all day long every day. So I'm blaming Scotland!
Anyway, many thanks for all the advice.
Tom.
 
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