High Speed Front End Wobble and Gas Leak

[Redlinesd1]

As I've read this is very common to these bikes. With mine it can start as slow as 160km/h although usually starts around 180km/h. For my bike I find that if I push against the bars I can get around it happening. I must keep pressure on them whether accelerating or decelerating till I get below 180. Had it up to 230km/h today which I believe was pretty much all mine will do. No wobble as long as I did this. Wondering if anyone else has had the same experience and if it's the weight or because the forks are compressed or both? Needless to say it's hard to do at speed with no windshield.lol Got a Fork Brace coming from UFO. Anybody had any luck with these helping? I also have a pretty major leak from the carbs somewhere but I haven't ripped it apart. I took it in to Yamaha to get fixed. Thought it was but same thing kept happening. 460 bucks and a week without my bike at the end of my first season later it's going back and they better fix it this time. Hopefully it don't take a week this time. That's what I get for going to the dealer I guess.lol Anyone dealt with this kind of leak before? I appreciate all the help as I'm a newbie to this bike and just trying to learn all I can.:clapping:

 

[dannymax]

There are almost as many possible causes for a wobble as there are bikes....wheel balance, tire size, wheel bearings, swingarm bearings, stearing head bearings bad or maybe too loose, rear tire balance, pressure, size....it just goes on & on.

Generally, switching to radials will cure it, but not always.

Gas leak sounds like a stuck float....did the fuel pump keep clicking, or is it a constant leak, like a float chamber gasket of bad fuel line?

As I've read this is very common to these bikes. With mine it can start as slow as 160km/h although usually starts around 180km/h. For my bike I find that if I push against the bars I can get around it happening. I must keep pressure on them whether accelerating or decelerating till I get below 180. Had it up to 230km/h today which I believe was pretty much all mine will do. No wobble as long as I did this. Wondering if anyone else has had the same experience and if it's the weight or because the forks are compressed or both? Needless to say it's hard to do at speed with no windshield.lol Got a Fork Brace coming from UFO. Anybody had any luck with these helping? I also have a pretty major leak from the carbs somewhere but I haven't ripped it apart. I took it in to Yamaha to get fixed. Thought it was but same thing kept happening. 460 bucks and a week without my bike at the end of my first season later it's going back and they better fix it this time. Hopefully it don't take a week this time. That's what I get for going to the dealer I guess.lol Anyone dealt with this kind of leak before? I appreciate all the help as I'm a newbie to this bike and just trying to learn all I can.:clapping:

 

[RaWarrior]

For my bike I find that if I push against the bars I can get around it happening. I must keep pressure on them whether accelerating or decelerating till I get below 180. Had it up to 230km/h today which I believe was pretty much all mine will do. No wobble as long as I did this.

DO NOT DO NOT DO NOT do this. Pushing against the bars may temporarily seem to stabilize the bike, but you're fighting against a force that is much stronger than you. If you hit a bump, frost heave, tar strip, anything, that wobble you're suppressing can and will instantly come back as a full blown tank slapper. As in the handlebar will be ripped out of your hand(with the power to snap your wrists) and you will crash. Somebody here actually had this happen to them. I actually found the Vmax was more stable at speed by deliberately keeping a loose, easy grip on the bars at speed. Crouch out of the wind and let the seat hump take the wind force, loosen the instinctive death grip on the bars.

I kind of doubt a fork brace will help much. The problem can be any of the things Dan mentioned, but it has been found that these bikes had literally crooked frames from the factory...poor wheel alignment. People that have had their bikes aligned (with a system like compu-trak) report a huge improvement in overall handling and stability.

I had these same issues with my '97 and tried everything. New tires, new head bearings, dozens of suspension adjustments, fork brace, frame braces, lowered the forks, Progressive springs. All that stuff helped the problem, made it a little less prominent, but it was never cured. I rarely pushed the bike much past 120/200kph. Just too squirrely for comfort. Vmax was designed for stoplight-stoplight acceleration....the top speed was kind of a side effect Yamaha didn't really consider into the design. Mine would run to 140-145....so about 240ish kph. Some people have bone stock bikes and no wobbles whatsoever, but these people seem to be the exception rather than the norm.

A stuck float or bad needle/seat is most likely the gas leak. There's an excellent picture tutorial in the carbs section, if you're handy you can probably fix it yourself.

 

[85vmax]

I have a '85 progressive springs and shocks, UFO fork brace, and frame brace, tire pressure at 36/40.....I have no problems pegging the speedo on a good day, and 145 comes quickly....get a weave every now and then if real windy.

My buddy with a '02 could never get over 115 without the headshake.....he got the UFO brace....nothing else, and added 15 mph....just did the progressive up front and down 1 inch......now he hits 145 speedo with ease.

I think all the maxes are different also....good luck.

 

[dannymax]

That hi-speed wobble scares the shit outta me!! Sometimes you get lucky and come out the other side of it unharmed....sometimes not. As RA said, it can turn into a full blown tank slapper in the blink of an eye....and you're just along for the ride after that, you are no longer in control.

There's a reason it's referred to as the 'death wobble'!

 

[Fire-medic]

I have a '85 progressive springs and shocks, UFO fork brace, and frame brace, tire pressure at 36/40.....I have no problems pegging the speedo on a good day, and 145 comes quickly....get a weave every now and then if real windy.

My buddy with a '02 could never get over 115 without the headshake.....he got the UFO brace....nothing else, and added 15 mph....just did the progressive up front and down 1 inch......now he hits 145 speedo with ease.

I think all the maxes are different also....good luck.

I travel "the opposite way" every workday on I-595, to/from "Day'-vee," please inform me when you customarily are running 145 so I can watch-out for your body racing your riderless bike after some Weston BMW or Infiniti or AUDI cuts you-off, and you are punted out of the saddle! Not that I want that to happen, but I have more experience than most what happens on the streets around here...I was just speaking w/the Davie Fire-Rescue Medical Director, and those guys stay pretty-busy between I-595 and I-75.

Biggest change in handling I made, aside from replacing worn tires, was in recently going to radials, and I don't mean "the Dark Side," running a 15" car radial! Well-worth the investment to do it right.

 

[85vmax]

I travel "the opposite way" every workday on I-595, to/from "Day'-vee," please inform me when you customarily are running 145 so I can watch-out for your body racing your riderless bike after some Weston BMW or Infiniti or AUDI cuts you-off, and you are punted out of the saddle! Not that I want that to happen, but I have more experience than most what happens on the streets around here...I was just speaking w/the Davie Fire-Rescue Medical Director, and those guys stay pretty-busy between I-595 and I-75.

Hey Fire-Medic....do you teach at BC...or freelancing....I have a bunch of "fire-medic" aquantances.....

Anyways.....sorry...5-10 over only on I-95...turnpike....I-595...maybe 15-20 over on I-75 and the Alley..........no cars around where I go......plus you know you need some room fo the Max to get to 150:rofl_200:

Do you know where the 200mph club runs?....they outa Miami.