scuff

Ah but were you figures obtained at sea level, or at higher altitude. Perhaps those riders who enjoy ragging their bikes around the Himalayas would care to compare with me if the pressure build up at higher altitudes causes less weaving problems than those of us at lower altitudes. My pressure tests were done at a local wind tunnel, and I found in fact that due to the shape of the ducting around the tracers rad, it actually passed 43.742789% of the air through. Right I'm off to blast around on my bike and find some sports bike riders to embarrass, when we stop to chat, I will bore the feck off of them explaining aerodynamics, and how it allows me to ride around them on corners because of it. (rofl)

Most of the air hitting the rad thankfully passes through it to stop our engines overheating. As the rad is angled forward, the air will hit the fins and if anything will cause downforce. To be honest, all of this talk of aerodynamics may make a difference on a formula 1 car or an aircraft, but I don't think it makes any difference to bikes with their slab like aerodynamics. Anyway, we could get really technical and put our anoraks on and say that as the wheels move through the air, due to their rotation the air will cause a low pressure area below the wheel and a high pressure above it, thus the Magnus effect will force the wheel down. That's it, bored now.

Don't forget that the angled screen and had guards will cancel it out any perceived air bubble by pushing down :-D I use a steering damper to keep the bike from going completely out of control, not to hide a problem that I am aware exists. Most people won't ride it to the extremes that may cause the weaving, it's when you take it by the scruff of the neck and wring the nuts off of it, cranked over and braking with the rear wheel lifting off of the ground on our bumpy and broken up British back roads. I am happy to ride it within its envelope, it is still good fun and a very capable machine. Just be aware that it has limits which could surprise you one day when you are really trying. :-)

Same here Milton. I have resolved to keep the aggression down as much as possible. My steering damper just about keeps it under control, but I cannot ride the bike to its limits with confidence. Whilst it is frustrating, I still think that the bike is great for normal spirited riding. On a ride yesterday with some other bikers, I had just got past a fireblade around a left hander, and when returning to my side of the road I caught the white line while cranked over to the peg feelers. The resulting weave was very uncomfortable and difficult to get back under control. Many bikes that I have ridden will often get a wiggle when under the same circumstances, but they sort themselves out fairly quickly, this bike doesn't. If you try to slow down quickly whilst in a weave it will often make the problem worse. I have found the best way is to brake hard with the rear brake to help slow down without loading up the front.

So why hasn't everyone done it skip. On the contrary, taper bearings are prone to more wear and seizure if incorrectly adjusted, but if fitted properly will improve life over roller bearings as the tapering resists lateral movement better than ball bearings. And you still can't adjust them for the conditions etc.... I know I'm not going to convince you all, so I'll leave you make your own choices.

Unfortunately, incorrectly adjusted steering bearings would be a failure for an MOT test. And possibly an offence of using a vehicle in a dangerous condition, as it would be outside the specs of the design and manufacture. In order to get some resistance on the bearing, they would have to be over tight.

With respect, I really don't suggest that you tighten the head bearings. If you do, they will indent the bearing race and damage them, the steering will be jerky and notchy. A steering damper gives smooth resistance with no notchiness, and is adjustable for different riders and conditions.

Hi scuff, did this happen with your steering damper installed ?This was before the damper fitting. If I now adjust it to about click 11, I find it is a good compromise between being able to steer when riding slowly, and stopping the wobble from getting out of hand. if you are doing drag racing, wind it up to 20 and lose all ability to steer.

I have the 138mph footage, but have blurred the speedo for the edited video, just in case...

I have had an indicated 138, it was still pulling, but steering was getting seriously wobbly, although the track I was on was quite smooth.

Jodhpurs, ouch. Seems Old Bill has actually made progress over the years. Do you still wear a flip-up on your Tracer? I am considering one but don't know what the disadvantages would be, more noise I guess for one. But I sometimes get very hot and almost claustrophobic in my full face helmet in summer and it would be nice to flip it open at stand still.I've pretty much always used a flip front helmet Johan. I'm wearing a Caberg justissimo GT at present, it was fairly easy to strip out and install microphones for the comms. and one for the camera. I can also quickly chuck the lining in the wash. It is useful to be able to flip it up at traffic lights etc. and for when I need to chat to a student briefly. it is going to be heavier than a standard helmet, but I don't mind this. It's probably noisier, but I always wear earplugs. In fact I feel that it vibrates less than a light helmet due to the inertia required to move the heavier weight.

Do you get a choice of helmets? If not do they custom fit to individual's heads? I have a torrid time trying to get a helmet to fit and it seems I have to go with the Japanese makes as I don't have a Teutonic or Italian shaped head.I'm retired now, but of all of the types and makes of helmet that I was issued with, I had no choice about the make or model. Just had to accept the one which was being purchased over that period. Before the days of H&S, we wore fabric horse riding Jodhpurs and nylon jackets. Our helmets were half faced and we were issued with a pair of stadium split screen goggles (of which I still have an unused pair). Make me laugh and shudder at the same time. I finished up with a BMW full face hemet and made to measure BKS leathers with armour fitted!

Quite a few of us have clear visors, under which is a flip up shield. That's perfectly legal, it's just like wearing sunglasses. Interestingly, if you have your dark shield down, and then flip up the clear visor..........

Great stuff Pilgo. Mine generated a lot of interest today as well. The local IAM group run to Grafham water, I think at least one rider will be going to arrange a road test at a local Yamaha dealer.

Fairly quickly

Here is a short video of the steering wobble. Yamaha city side case were fitted and full of heavy cameras and lenses. [video src=https://youtu.be/JK_ICBQuh30]

However the wobble is set off, it needs to be controlled. The caster effect sets up an over correction to straight ahead (like a shopping trolley wheel), and the resulting oscillation can result in a very nasty tank slapper. You cannot stop it physically. It can often help by shifting forward and leaning over the tank. The steering damper is a safety net, if and when the oscillation starts, it is damped and controlled. The FJ is not unique, it can happen on virtually any bike.

Like this....

On this forum Here

But if you removed the hand guards, you are still left with mirrors, hands, arms and levers etc. stuck out in the airflow. I would suggest that ha guards are more aerodynamic than whatever is behind them. Ultimately, I am happy that normal and even spirited riding does not cause any issues. Having fitted a steering damper, my bike is now rock solid no matter how much I try to induce a wobble with harsh acceleration, cranked over riding over lumps bumps and cats eyes, bouncing off of the traction control etc. it still even steers very quickly, but without any nervousness. Even at really high speeds and with Yamaha hard city cases fitted.

Or put a steering damper on it. The suspension works fine, it's the super quick geometry and wheelie power that promotes the wibblies

I have found the steering wobbling, with and without the hard bags. It is less pronounced without the bags mounted. My riding conditions were a B road with a reasonable surface and high speed (110mph) bends. There were very gusty winds, and I was riding it very hard with the traction control cutting in on occasions. I checked tyre pressures, sag, and damping as well has steering head and swingarm play. The screen was set in the middle position. I would suggest that this wouldn't really be a problem when riding at a sensible touring pace. I have ordered a steering damper which should be here soon, which should help to alleviate the behaviour.

My hard case mounting stays arrived from the USA today (they are not available to order in the UK). It only took a couple of weeks to arrive via USPS. It didn't take long to fit them, and they are very strong and solid. My hard city cases fit on very securely and look really good on the bike. I couldn't be more pleased 8-)

Great mod, thanks everyone. I now have a disclock/screamer, puncture repair set including CO2 cartridges, toolkit, and visor cleaning sponge and fluid, and finally the USB adapter for the accessory socket all stashed under there. The mod took a couple of minutes to cut out and smooth down with my dremel.