Bike Instability above 70mph on interstate

Sorry for the noob question...but I cannot find anyone with my specific issue.

I have read a lot of other issues with people with a "wobble" at certain speeds, but none at my speed.

I have 2003 FJR1300 with stock side cases and top case.

My issue is a "loose" feeling at the front end at speeds above 70mph. Especially 80mph and above. Mostly on the interstate around other cars and definitely 18 wheelers. I know that you will feel some turbulence from other cars, but this is worse than I am used too. I have ridden multiple other bikes (mostly cruisers) at these speeds and felt much more stable and confident in the same conditions.

The FJR being a more aerodynamic machine I would expect it to be even more stable and higher speeds...so I definitely feel there is something wrong. I feel like this bike should be able to go down the interstate on long trips, but I currently have no confidence in the handling at those speeds around cars. I feel like I have to fight the bike too much to keep it straight in the lane due to the feeling of wind pushing me around. The bike is buttery smooth in ALL conditions below these speeds, even around cars and trucks. Total confidence while riding. Bike has zero wobble at any other speed. I can ride with my hands off the bars with zero shake. I did this just to test. The feeling isn't really a wobble at all. The handle bars don't shake any. It just feels all over the road and will not track straight without steering input.

Rider: 275 lbs. Testing done with low to no extra weight besides me.

Bike Setup:

1.New tires. Dunlop RoadSmart 3's (installed the wheels back on the bike and torqued everything myself) Tire pressure at 36,38

2.national cycle vStream windshield. (wind effect feel almost the same up or down. All mounting bolt tight.)

3.Suspension all set equal on both sides (compression, pre load, and rebound). Fork tubes at equal height.

4. I do have both side and top case on the bike. I have tried removing the top case with some help, but the issue is still there. I also want to be able to use the top case on trips....

It almost feel like the front wheel axle is "loose" in the stated conditions. But it checks out with the torque wrench. I can see this causing high fatigue on the highway at these speeds, so I really need to get this hammered out before Spring

Makes me kinda sick because I have put almost 500 miles on the bike since I have gotten it and never experienced it until I set out on a longer trip that included some highway driving.

Any help is greatly appreciated!

Properly set up, the fjr is very stable at speeds north of 100 mph, damhik. Many of us run our tires at 40 front and 42 rear which may help. You might want to check the triple tree bearings for proper wear and torque.

Up your tire pressure to 40 F and 42 R as a start. Stiffen up your suspension as well. It will feel like a new bike.

The big windshield and the top box may contribute to some instability, especially in turbulent air around trucks or in crosswinds. Should be manageable.

Make sure the tires are mounted in the correct rotation!!

Ditto on tire pressures..I run 39/40, my bike is stable to 255km/hr ( indicated)

What you did last is generally a good place to start when chasing a problem; New Tires. You could have a bad tire, a bead not properly seated or, as suggested above, a tire mounted in the wrong rotational direction.

A large windshield will get buffeted around in the turbulent truck air-wash. If you’re not used to how that feels this could be what you are experiencing. Personally, I dislike riding a motorcycle on the interstate unless it is very light traffic. Just not that much fun, IMO.

Inflating both tyres to 42/42 made a world of difference to mine.

However, I remain somewhat unconvinced by the bike's stability in crosswinds and particularly with a taller screen, dreadful Limey heretic that I am.

Sounds like what happens with a car tire at about 110. Not a wobble in the handle bars but a weave affecting the whole bike, like a cross wind is pushing/stopping making you drift back & forth all the time.

Follow the others' advice- up the tire pressure, suspension, etc. Also, new tires, especially when the front & back are replaced at the same time, to me feels twitchy & often the slightest, almost imperceptible, input cause the bike to weave. This bike is to me especially susceptible to this so I NEVER replace both tires at the same time. Check the steering bearings. Loosen the front axle and bounce the front end, maybe there's a little misalignment there. I've found the larger windshield & top case causes a little wobble in high winds but nothing like described in normal riding.

Please come back and tell us what you find.

ThwartedEfforts said:

Inflating both tyres to 42/42 made a world of difference to mine.
However, I remain somewhat unconvinced by the bike's stability in crosswinds and particularly with a taller screen, dreadful Limey heretic that I am.

Click to expand...

As another limey heretic, I find my FJRs no worse than other bikes with windscreens that I've ridden at motorway+ speeds.
Best advice I have is (apart from the tyre pressures etc people have mentioned above) is try to relax more, guide the bike with loose arms, don't fight it. Yes, it will suffer in turbulence from other vehicles, but it will track true if you let it. Same with cross-winds. The old adage "look where you want to go" applies here as in all motorcycling.

You gave me a flash-back with this thread. In my first year or so with my '04 I typically chased the perfect windshield/helmet/seat height solution to ease the buffeting. Sometimes it was bad enough that, like you've described, the bike was being moved all over the lane. Then at some point I recall being alone on a ride somewhere off of Long Island and was amazed when seemingly all of a sudden the bike had become so quiet and stable. WOW! Did I finally succeed at finding the right combination of things I asked myself. No dumbass, you finally got away from all the stupid traffic congestion and found some real riding areas! After making that 'discovery' I pretty much accepted it for what it is and just learned to expect a bounced around ride whenever on the major roads around here. Well that and a continued appreciation for real "motorcycle roads". Best of luck with your bike.

You have "setup' your suspension, but are you still using the stock shock and fork springs? The Gen I is seriously under sprung for a 275 lb. rider. Tire pressure may help, but replacing that old shock with a new Gen III or aftermarket shock will transform the bike. The 2003 had the weakest suspension of all Gen I models. Yes, the Gen III shock is compatible...while you are at it, change the cam chain tensioner.

Thank you all so much!
I will try the higher tire pressures first. I did check when installed and just checked again for assurance, both are set up in the correct direction, as well as the wheels themselves ( not sure if you could even install them backwards).
The suspension pre-load is at maximum (no lines left, since I am heavy) but still has the weak stock springs (baddd nose dive on braking). I plan on rebuilding the front forks and installing HyperPro springs and also installing a HyperPro spring and shock in the back in January. All is original with 45,xxx miles so i figure it is a good time to replace it all.

If the tire pressure does not work, I will check the bearings mentioned above next.

I did take the bike out for some testing for over 2 hours last night after posting this and here is what I gathered.

all cases on the bike - same result as before
top case off- bike felt more stable at speed, slightly more stable passing a truck, but still not super confident at all.
All cases off - Mostly the same as just the top case off. Maybe slightly better but probably not any better, just in my head.
All cases on plus a pillion rider - Felt more balanced and more stable at speed. Still not super confident while passing a truck, but some better. (The bike handled a pillion a lot better than I am used to on a cruiser...Impressed)
In all situations above, I tried the windshield in multiple positions. All the way down was the most improvement, but still not really that good, plus I want to use the screen at least half way up to cancel buffeting.
In all situations I was cruising at ~80mph for testing. All on the same stretches of road just repeated over and over.

I will agree that on a back road with zero traffic...the bike handles 75% better at 80mph...but I feel like it should do better on the highway...

In no situation did I feel confident to go cross county on the bike just some were better than others.

rbentnail got it right. It drifts back and forth about 4 inches on the front while behind a big rig. Even 15 car lengths back it is still noticeable. My biggest issue is passing a big rig. It feels so sloppy that I don't think I would want to try passing one in a curve... Almost has the feeling of almost no weight on the front wheel.

I will do more testing and let you all know what I find! I really appreciate all of the help!

Brian.

Your final comment of Almost has the feeling no weight on the front wheel sounds like you may have the situation of so much sag in the back that the front end is extending at speed (all bikes get lighter in the front at speed) and the fork springs are so weak they are not pushing down hard enough to make good contact with the pavement.

You can test whether that is happening by lowering the front end (all lines showing on the preload), lowering the windshield, taking off the bags and trunk, and turning up the compression damping. I doubt this will totally fix your problem since you will still have a bike with excessive sag on both ends but if it is an improvement in straight line stability or if it pushes the instability to a higher speed then you will have a good idea of what you need to fix the problem....much heavier springs on both ends.

YES to what TomInPA said. At your weight, an OEM shock (even if it is in new condition) is going to be woefully undersprung. And YES to how sensitive an FJR is to underinflation of the tires F/R - should be between 42/42 and 40/40 for the sweet spot. I like 40/42; much under 40 on either can feel surprisingly wrong.

Having said that, here's one other discovery I made with suspension set-up back in 2007. I have a Muzzy 4-2-1 exhaust system that would scrape on compression in hard turns before I beefed up the spring rate at GP Suspension in 2010, even though I had a Wilbers aftermarket rear shock (which was heavier sprung than the OEM shock and had an adjustable height feature at the lower clevis). I'm 175 lbs, though I was 10 - 15 lbs heavier then.

In an effort to stop the header collector from scraping, I experimented with raising the rear using the aftermarket shock's adjuster, taking it out to test changes while I tried to get it right. Be damned if this bike (my '05 is a Gen.I like yours) isn't hella sensitive to messing even a little with the geometry of the suspension. On the interstate, above about 60 mph, the higher rear made the bike feel like it was hunting - too ready to change direction, even wander out of my lane if I didn't have an attentive hold on the bars, paying attention to that wander at all times. I spent a couple days at that before going back to stock geometry and living with hard turn compression occasionally causing the exhaust system to scrape.

Three years later, I did a ride-in to GP Suspension and was amazed at how undersprung my aftermarket shock that they rebuilt was from what they recommend for an FJR at my weight. They got the suspension right, left the geometry at stock and the thing has been a dream ever since, without header collector scraping.

My son, who is close to your weight, had a ST1300 that gave him this vague feeling at pretty much any speed. I (180 lbs. geared up) rode it and noticed no such problem. We cranked up the preload in the rear and his problem went away.

BGR , This concern was also big on the ST1300 and Honda said 'Don't ride fast w/ all 3 bags'.

Common sense says it's the wind / buffeting getting all confused and sideways with 3 bags. It should be best w/ no bags, lower (smaller) shield, and stiffen tires and suspension.

Short of the ideal... I ride w/ a trunk but no bags and it's smooth. Add a (light) bag to the back seat to aid in smoothing out the air flow.

Re - visit your sag and maybe adjust the front and rear suspension. I hate to say it, but you and a pillion are probably going over the GV Weight limit.

Still, there is always room for improvement.... keep adjusting and report back.

You've gotten more advice than you bargained for, I'll bet. I won't add to it -- mostly because my comment's about keeping tire pressure above 40 psi, too. What I will say is this:

1) MANY riders here, perhaps including me, have ridden MANY miles near, at, or above 100 mph without issues. Wouldn't surprise me at all if the collective "we" have ridden 100,000 miles at or above 100 mph or it's kmh equivalent, with hardcases, topboxes, tank/tail bags, and lots of other crap aboard. The FJR is a solid performer at that speed, even when heavily laden.

2) I commute almost every day, and almost every ride consists of 10 miles at or near 80 mph. The FJR is a solid platform at that speed, and I always have hardcases and a a topbox.

3) After a few thousand miles, you can tell when your front or rear tire is a little low on air.

a. Front: soft 'bumps' at cross-wise pavement seams, and bike follows longitudinal pavement seams. You have to wrestle it off those seamy suckers.

b. Rear: bike wallows in turns, fails to track well in a straight line, feels loose most of the time -- especially in windy conditions, and will get a little slippery when you lean it over.

FWIW, on my '13 with myself and wifey (total 290-300 lb.) and suspension set "Hard" no problems at any speed I've driven, so far about 95.