"Jumping" FJR

[Esa]

I have an ongoing problem with the front of FJR 1300 model 2015. The front and rear tyres are brand new, front chockabsorbers have been tested and oil & oil seals changed, front and rear tyre bearings have been changed, front tyre rim is also brand new. However, despite all these actions taken the bike is "jumping" and especially this phenomen appears when driving with 50-90 km/h on tarmac road. Any idea what might be the reason for this???

 

[RossKean]

Not sure what you mean by "jumping". Are you talking about "headshake" (handlebars oscillating, especially while decelerating)?
If so, a front tire is often to blame (even a new one can be bad). It is worth checking the torque on the steering head bearings. Some people have found that replacing the original bearings with a set of tapered bearings and races eliminated this problem.
Also, loosening the pinch clamps and axle and compressing the suspension a few times by pushing down on the handlebars and bouncing the front wheel can help align the front end. Tighten with correct torque afterward.

Edit: If it is something other than "headshake", I would need to know more. Does your bike have the regular suspension or the electronic suspension?

 

[Whooshka]

By "jumping" do you mean "bouncing"? Start with 3 easy things...

1) Set tire pressures to 41/42
2) Make sure the front wheel and tire are balanced correctly. Take it to a shop if you don't have a balancer.
3) Set your suspension. Start in front with 3 lines of preload showing, 8 clicks out from full in on rebound and compression damping. These settings work well for a 200 pound rider, I don't know your weight. On the rear shock set preload on soft and rebound 8 clicks out also.

If all of these things have no effect I'd say you have front tire that isn't mounted correctly (check the rim/bead all around on both sides) or you have an out of round tire.

Worse case is when hey changed out the fork seals and bits they didn't reassemble the forks correctly.

 

[BigOgre]

Only one question just so there's no confusion: Did you have all that work done in order to solve the "jumping" problem or did the problem come about after the work was done?

 

[sapest]

4th easy thing - are both tires mounted directionally correct?
-Steve

 

[Martin Quigley]

Have you had both wheels ballanced sounds like when you reach a certain speed the problem starts if your wheels or tyres are out of ballance this would cause a vibration wheels would start to shudder and give the bike that jump type feeling,what make and brand of tyre have u fitted best tyres are michelin or Dunlop,,

 

[graytaz]

best tyres are michelin or Dunlop

Them's fighting words. We should be able to start another never ending thread based on that comment.........

 

[vzhq16]

@Esa Why was the front wheel replaced? I'm not certain what you mean by "jumping". My best guess would be an out of balance or out of round condition. Either is easily verifiable by removing the front wheel from the bike and re-checking both. Make sure when you re-install the front wheel that you follow the manual's instructions to the letter. It can/will make a huge difference if done incorrectly.

 

[RossKean]

I had initially assumed he was referring to headshake. Oscillation, especially during deceleration. Not actually jumping, but instability.

If the wheel is really "jumping" or bouncing up and down, I would be looking at a bad tire or one where the bead didn't seat correctly. Try breaking the bead on both sides, lubing the bead and resetting it.

Consider increasing damping and decreasing rebound if everything else is OK.

 

[Esa]

Not sure what you mean by "jumping". Are you talking about "headshake" (handlebars oscillating, especially while decelerating)?
If so, a front tire is often to blame (even a new one can be bad). It is worth checking the torque on the steering head bearings. Some people have found that replacing the original bearings with a set of tapered bearings and races eliminated this problem.
Also, loosening the pinch clamps and axle and compressing the suspension a few times by pushing down on the handlebars and bouncing the front wheel can help align the front end. Tighten with correct torque afterward.

Edit: If it is something other than "headshake", I would need to know more. Does your bike have the regular suspension or the electronic suspension?

Thank you for your most valuable response. I´ll convey your info to the persons in charge of the maintenance. "Jumping" feels like there is a stone stuck in the front tyre and the more I accelerate and drive more than 100 km/h the problem is not that prominent but still exists. The front tyre (Metzeler) has been changed three times anticipating that the tyre lining or the Metzeler model is not ok but this did not make any difference. The front rim was changed because the maintenance person believed / tested that it is not 100 % round. I doubted this seriously since I have not driven the bike on gravel roads at all, the bike has never had any collision or fallen down or anything like that and has only 31000 km "carefuL driving". Finally the Metzeler was changed to Pirelli and this alleviated the feeling but did not abolish it. The rear tyre is Metzeler and both the front and rear bearings are brand new. The bike has regular suspension and cartan shaft. The torque on the steering head bearings ha salso been checked.

 

[Esa]

By "jumping" do you mean "bouncing"? Start with 3 easy things...

1) Set tire pressures to 41/42
2) Make sure the front wheel and tire are balanced correctly. Take it to a shop if you don't have a balancer.
3) Set your suspension. Start in front with 3 lines of preload showing, 8 clicks out from full in on rebound and compression damping. These settings work well for a 200 pound rider, I don't know your weight. On the rear shock set preload on soft and rebound 8 clicks out also.

If all of these things have no effect I'd say you have front tire that isn't mounted correctly (check the rim/bead all around on both sides) or you have an out of round tire.

Worse case is when hey changed out the fork seals and bits they didn't reassemble the forks correctly.

Thanks for your prompt reply. See also what I replied to Ross Kean. Next week I´ll have the tyres balanced once again with another service person and raise your reply with them also.

 

[Esa]

Only one question just so there's no confusion: Did you have all that work done in order to solve the "jumping" problem or did the problem come about after the work was done?

Thanks for your comment. The problem appeared before the work was done. Originally I thought that it was due to the outworn front tyre which was the main reason I took the bike for service.

 

[Esa]

4th easy thing - are both tires mounted directionally correct?
-Steve

Will check next week by another service person.

 

[Esa]

Have you had both wheels ballanced sounds like when you reach a certain speed the problem starts if your wheels or tyres are out of ballance this would cause a vibration wheels would start to shudder and give the bike that jump type feeling,what make and brand of tyre have u fitted best tyres are michelin or Dunlop,,

Thank you for your comment. WIll check again next week. Pirelli is in front and Metzeler in the rear.

 

[Esa]

Them's fighting words. We should be able to start another never ending thread based on that comment.........

OK

 

[Esa]

@Esa Why was the front wheel replaced? I'm not certain what you mean by "jumping". My best guess would be an out of balance or out of round condition. Either is easily verifiable by removing the front wheel from the bike and re-checking both. Make sure when you re-install the front wheel that you follow the manual's instructions to the letter. It can/will make a huge difference if done incorrectly.

Thank your for your response. See what I´ve commented to Ross Kean and others.

 

[Esa]

I had initially assumed he was referring to headshake. Oscillation, especially during deceleration. Not actually jumping, but instability.

If the wheel is really "jumping" or bouncing up and down, I would be looking at a bad tire or one where the bead didn't seat correctly. Try breaking the bead on both sides, lubing the bead and resetting it.

Consider increasing damping and decreasing rebound if everything else is OK.

OK. The "jumping" feels like "bouncing up an down" without really shaking the handlebars like it would do if the tyres are not in balance.

 

[sapest]

Will check next week by another service person.

You can do this, there will be an arrow molded on the tire sidewall. Make sure its pointed in the correct direction, ‘forward’. Something like this :

-Steve

 

[Lost]

Assuming it's not an out of round tire, then I think the problem is 2 different brands of tires. Different tire construction or aspect ratios can cause interesting handling problems.

 

[VAcracker]

Not sure if I fully understand a jumping tire. But I have felt excess vibration or excessive jarring through bars when the steering stem was little loose.