MK3 wobble

Joined
Mar 4, 2014
Messages
25
Country flag
My Mk3 on California freeways wobbles around more than I care for. The rain grooves always made my Nortons walk around some but this is like a GP bike on the pipe coming out of a corner. I replaced the Isos and the rear wheel bearings, tires are new and balanced, the swingarm pivot appears tight. No apparent movement in the steering head. I put Dunlops on (was Avons) and it didn't help. Suggestions?
 
Joined
Dec 28, 2009
Messages
3,710
Country flag
Resurfacing grooves on the highway are terrifying at best. Oddly enough the better your tires the worse it all gets. We wrote a letter to our Ontario Ministry of Transportation head about this motorcycle issue and he said we post signage saying : Resurfacing Ahead . Did the 401 several terrifying times this year to leave/return to Toronto . No signage , no warning , sudden terror followed by survival slowdown with big trucks blasting horns. Fun.
 

baz

VIP MEMBER
Joined
May 26, 2010
Messages
2,519
Country flag
My Mk3 on California freeways wobbles around more than I care for. The rain grooves always made my Nortons walk around some but this is like a GP bike on the pipe coming out of a corner. I replaced the Isos and the rear wheel bearings, tires are new and balanced, the swingarm pivot appears tight. No apparent movement in the steering head. I put Dunlops on (was Avons) and it didn't help. Suggestions?
Are you still on standard 19" rim's?
What Avon's did you remove IE roadrunners or roadriders etc
One thing that made a difference on my bike was going from an 18" back to a 19" rim on the back
And fitting roadriders front and rear
Has your bike always been bad? What's the history?
Cheers
 

HRD

Joined
Mar 21, 2011
Messages
85
Country flag
My Mk3 on California freeways wobbles around more than I care for. The rain grooves always made my Nortons walk around some but this is like a GP bike on the pipe coming out of a corner. I replaced the Isos and the rear wheel bearings, tires are new and balanced, the swingarm pivot appears tight. No apparent movement in the steering head. I put Dunlops on (was Avons) and it didn't help. Suggestions?
Have you checked the front wheel spoke tension and rim run out. Also the condition of the head steady rubber bobbins, has one or both of the rubber bobbins separated from the stud area , can be difficult to see without removal of the side plates .
 
Joined
Mar 4, 2014
Messages
25
Country flag
Are you still on standard 19" rim's?
What Avon's did you remove IE roadrunners or roadriders etc
One thing that made a difference on my bike was going from an 18" back to a 19" rim on the back
And fitting roadriders front and rear
Has your bike always been bad? What's the history?
Cheers
It had roadriders 18" rear 19" front. I bought it last year, it had a low speed shimmy when I let go of the bars but that went away with the new tires.
 
Joined
Mar 4, 2014
Messages
25
Country flag
Have you checked the front wheel spoke tension and rim run out. Also the condition of the head steady rubber bobbins, has one or both of the rubber bobbins separated from the stud area , can be difficult to see without removal of the side plates .
The front spoke tension seems good but I have not looked at the head steady. I'll do that.
 
Joined
Mar 4, 2014
Messages
25
Country flag
Resurfacing grooves on the highway are terrifying at best. Oddly enough the better your tires the worse it all gets. We wrote a letter to our Ontario Ministry of Transportation head about this motorcycle issue and he said we post signage saying : Resurfacing Ahead . Did the 401 several terrifying times this year to leave/return to Toronto . No signage , no warning , sudden terror followed by survival slowdown with big trucks blasting horns. Fun.
Here in Ca, they cut rain grooves but it's more than that.
 
Joined
Mar 4, 2014
Messages
25
Country flag
Are you still on standard 19" rim's?
What Avon's did you remove IE roadrunners or roadriders etc
One thing that made a difference on my bike was going from an 18" back to a 19" rim on the back
And fitting roadriders front and rear
Has your bike always been bad? What's the history?
Cheers
The front spoke tension seems good but I have not looked at the head steady. I'll do that.
Looked at the head steady the rubbers seem ok but I had new ones on the shelf so I installed them. I don't think that was it.
 
Joined
Mar 4, 2014
Messages
25
Country flag
I have no idea what the history of this bike is other than it was owned by the pres. of the Norton club in So.Cal. or so they told me. I bought it last year and it was not very stable. I had a near new 750 back in 72 and I could surf it going down the road, same model tires. I don't know, maybe because he put an 18" rear wheel on it and it upset the geometry. I can't see any unauthorized movement in the swingarm or clunking or clicking but I guess that's next.
 

baz

VIP MEMBER
Joined
May 26, 2010
Messages
2,519
Country flag
I have no idea what the history of this bike is other than it was owned by the pres. of the Norton club in So.Cal. or so they told me. I bought it last year and it was not very stable. I had a near new 750 back in 72 and I could surf it going down the road, same model tires. I don't know, maybe because he put an 18" rear wheel on it and it upset the geometry. I can't see any unauthorized movement in the swingarm or clunking or clicking but I guess that's next.
What size tyre is on the back?
Sometimes people go too wide when they go down to 18" rims
 

gortnipper

VIP MEMBER
Joined
Nov 11, 2013
Messages
3,329
Country flag
Have you checked/changed the fork oil?

How are the rear shocks? Tight and set up correctly?

Is your rear tire centered correctly and running inline with the frame?

And as a real wildcard, look at rhe frame tubes above the z-plate gussets. I bought my bike with rhe frame cracked there from the PO over tightening the ISOs. It walked all over the place.
 
Joined
Nov 10, 2006
Messages
1,308
Country flag
A Mk3 850? Check the two s/a spindle cotter pins are tight.
Dave
 
Joined
Jan 4, 2014
Messages
484
Country flag
Resurfacing grooves on the highway are terrifying at best. Oddly enough the better your tires the worse it all gets. We wrote a letter to our Ontario Ministry of Transportation head about this motorcycle issue and he said we post signage saying : Resurfacing Ahead . Did the 401 several terrifying times this year to leave/return to Toronto . No signage , no warning , sudden terror followed by survival slowdown with big trucks blasting horns. Fun.

Surprisingly those groves don't seem to bother my MKIII much unlike my Suzuki 750, which hated them. Back when many of the local bridges were steel grate they were a terrible ride but they've all been replaced. CA rain grooves aren't all that deep so I'm surprised they cause much trouble. They certainly don't slow down the lane splitters who go through the traffic at warp 7 or so.
 
  • Like
Reactions: baz
Joined
Mar 4, 2014
Messages
25
Country flag
Surprisingly those groves don't seem to bother my MKIII much unlike my Suzuki 750, which hated them. Back when many of the local bridges were steel grate they were a terrible ride but they've all been replaced. CA rain grooves aren't all that deep so I'm surprised they cause much trouble. They certainly don't slow down the lane splitters who go through the traffic at warp 7 or so.
They never bothered my 72 much either.
 

baz

VIP MEMBER
Joined
May 26, 2010
Messages
2,519
Country flag
Plenty of people will disagree with me here but I had a 4.70 x17 in the back of my commando but had bad weaving then a 4.25 X 18 roadrunner still bad weaving especially above 80mph or so
Then I fitted a 19" rear wheel actually a CMA mag that I had laying around with a knackered tt100 fitted
The difference was night and day
I had the hub rear laced up yet again (actually an apprillia hub not that it makes any difference) to a 19" wm3 rim and now I use a 90/90 19 roadrider on the front and a 100/80 19 on the back
No tracking on lines no weaving no steering damper needed at any speed
I think fullauto's wider rims would be worth looking into imo
 

baz

VIP MEMBER
Joined
May 26, 2010
Messages
2,519
Country flag
Maybe try a narrower tyre on the back if everything else checks out
 

baz

VIP MEMBER
Joined
May 26, 2010
Messages
2,519
Country flag
Forgot to ask, do you have just one mirror by any chance?
 
Joined
Dec 14, 2010
Messages
14
Country flag
Hello

I had also problems when the road was not plane, I replaced the original shocks with new Hagons and it improved.

BTW, I have also a MK3 with 18" rear and 19" front wheel, the 18 rear wheel with modern Tyres was an improvement over
the old narrow tyre.
At the moment I have a Michelin Pilot Activ 4.00 x 18 on a MT2.5 Akront rim, the overall diameter of the tyre is the same
as with the original Avon AM9.

Marcel
 
Top