Unsettled FJ11

[Urban_Legend]

Hey all. Went on a little 500km jaunt around the block today and the old girl is not handling as I think she should.
She is really unsettled in the faster corners (80kph +) rear end feels loose and "slippery" and gives a bit of a shake crossing the white lines. She still has the standard 16" rims with Bridgestone Battleaxe tyres - 6000km old, still good tread. Pressers are 36psi front and 38psi rear. Has new (6 month old Hagon shock) and standard front shocks, anti dive, rebuilt 6 months ago. Runs great in a straight line though.

Any ideas??? 

Mark

[charleygofast]

Check swing arm bushing slop...put it up on center stand and see if there's any side to side play by grabbing rear wheel and pulling it left and right. Also might wanna check rear suspension linkage bushings, and steering head bearings while you're at it. All of these can cause a shakey or "hinged" feel on your bike. You have a decent rear shock...how are your forks, are they set up properly? Hope this helps.                                                                           Charley.

[Urban_Legend]

I am waiting to pick up a set of 89 forks withb17" rim. Will rebuild this with Rpm emulator. New swing arm bushes installed. It has a new head stem bearing, but was thinking it may not be tight enough. I have given the "shake" test to the swing arm and didn't notice any movement.but I have been known to be wrong before.

Mark

[Firehawk068]

You will almost always get a little "Wiggle" if you cross the paint lines while cornering.
This is normal, no matter how your suspension is set up. Same with those pesky "Tar-Snakes" 
Try to stay off the painted lines. 

[red]

Hey all. Went on a little 500km jaunt around the block today and the old girl is not handling as I think she should.
She is really unsettled in the faster corners (80kph +) rear end feels loose and "slippery" and gives a bit of a shake crossing the white lines. She still has the standard 16" rims with Bridgestone Battleaxe tyres - 6000km old, still good tread. Pressers are 36psi front and 38psi rear. Has new (6 month old Hagon shock) and standard front shocks, anti dive, rebuilt 6 months ago. Runs great in a straight line though.  Any ideas???
Mark

Mark,

What are you running, for tires?  Are they getting old (age-hardened, not necessarily worn)?
That heavy-duty sunlight which you have in OZ is rough on tires; is the bike kept in shaded areas?

Check the front axle pinch bolts and axle nut, for torque.

Cheers,
Red

[Bones]

Mark, did you have your gearsack rack fitted on the ride, if so check your indicator mounts where the rack bolts on to make sure their not broken. If one side is broken and you have a little bit of weight in the bag, it'll shake when riding and give the impression something's loose on the bike, especially when cornering.

[movenon]

Hopefully it is just tires, loose rear wheels bearings, wheel alignment etc, etc.. If it has the wobbles the only thing IMO is do a complete inspection and adjustments from front to rear. Take nothing for granted. 

Out of the normal I might mention because of the bikes age there has been a couple of reported frame fatigue cracks.  Inspect closely around all the welded areas of the frame, around the motor mounts, shock attachment areas etc..  I know it is a little remote but worth a mention while you are checking things out.
George

[Pat Conlon]

Yep, what George said...
Especially those (4) M8 bolts at the rear mounting points of the lower engine cradle frame.

I was surprised to find 3 of the 4 bolts sheared off on a recent resto. I did....alarming to say the least.

[Urban_Legend]

Hi All

Thanks for the advice. Over the next week or so will be going over the bike. I am hoping it is just the tyres. They are not old (new in January) I hope I have lined up a new to me GSX rear for the bike so will whilst fitting that might take the swing are off and check all of the bearings. My forks were out of alignment before this ride (one was 2mm higher in the triple clamps)

Could having one of the anti dives operational and one not affect the spring rate? The adjustment on one of mine seems to be seized.

Pat - I will check the mounting points, they were ok when I put the jigsaw puzzle together, but they were not new, and fatigue may have gotten to them.

George - the wheel bearings were new in January, and I check the rear alignment at the man shed day at Bones place in Brisbane. (will check the torque settings - I have a new torque wrench I am wanting to test out.)

Bones - I did have a gear sack on the bike (empty) and the mounting points seem ok. Mine is not mounted to the blinker mounts.

Red - I have standard spec Bridgestone Battlax (BT45) tyres that are only 6000km old (new in January) the bike is always garaged (no direct sunlight) when not in use. I am not a fan of these tyres as I have already had one low speed off (in the wet) that I am blaming on the tyres.

Thanks again

Mark

Mark

[Urban_Legend]

Ok. here is what I have learned.
1. the frame bolts are fine. not sheared off.
2. Did the wobbles test on the swing arm. Solid as a rock.
3. Did a visual inspection of the frame. Looks ok.
4. Head stem. I got about a 1/4 turn tighter. (does not seem to be over tight)
5. gear sack nice and firm.

Could having the rear shock too soft/hard cause the unsettled behaviour of the bike? Again, it is a New Hagon Shock, just bolted in unchanged out of the box.

Ta
Mark

[Pat Conlon]

Rear shock?
Sure, that could do it if you did not set the preload on the spring correctly or set the rebound.
Did you measure the rider sag?

[Urban_Legend]

Rear shock?
Sure, that could do it if you did not set the preload on the spring correctly or set the rebound.
Did you measure the rider sag?

Short answer is no. I have no idea about preload and rebound.

[Urban_Legend]

Rear shock?
Sure, that could do it if you did not set the preload on the spring correctly or set the rebound.
Did you measure the rider sag?

Short answer is no. I have no idea about preload and rebound.

Ok Pat. Have seen the YouTube (right up there with Dr Google) how too for shock adjustment. No this has not been done for my bike, and after the presenters description on how the bike reacts to different preloads, I am thinking mine is too soft.

Trial and error time. (next weekend maybe)

[Bones]

Is it something that's just started happening Mark, or been there all along. How was it before you had your low speed prang, maybe it bent something somewhere.  A front end wobble can be caused by something wrong with the rear end, and vice versa.

I've never touched the preload on my Hagon, only the damping, their set at the factory for a rider between 70/90 kg, and although I'm heavier than that, Its never bottomed out with me on it so I've left it.

[Urban_Legend]

Hey Bones

Have never felt really comfortable since I screwed it together. It has never really inspired confidence in the faster corners. The Brakes aren't brilliant (still the original callipers, part of the reason I really want to upgrade the front). My previous bike (Triumph Dayton 675) allowed me to ride far beyond my abilities and inspired confidence with every turn. I just don't feel comfortable with the current setup  and feel of the FJ, but still wouldn't trade it for anything. Unless the corner is race track smooth, it wriggles around like a cut snake. With each little change I do it does seem to improve.

Front shocks do feel really soft, compared to anything else I have ever ridden. I just don't know enough about shock (front and rear) set up to diagnose the issue.

Mark