New vmax owner headshake

[jfeagins]

^ and yet over inflation causes the exact problem you describe.
If you run your front tire at 39-40 psi you can expect to experience cupping which wil cause the high speed wobble you describe.
The Owners maunual was printed by Yamaha for a reason.

I run 40psi in my OEM Dunlops. Have for 27 years now. I've never had a front tire cup on me on this Vmax. I've never heard of cupping causing a high speed weave either. I can see it causing a bunch of vibrations at speed, handlebar shake, but not wobbling. I've always thought that underinflation was the most likely cause of cupping. :ummm:

Learn something new every day.

 

[Saint]

It is definitely better now but i still felt it starting at higher accelerating speeds while changing lanes, and a quick back and forth 4-6 times when I let off... so I guess as long as I go straight and never slow down Ill be good

I think Ill find a spanner wrench and try the head steering bearing again...

 

[DMAN999]

I run 40psi in my OEM Dunlops. Have for 27 years now. I've never had a front tire cup on me on this Vmax. I've never heard of cupping causing a high speed weave either. I can see it causing a bunch of vibrations at speed, handlebar shake, but not wobbling. I've always thought that underinflation was the most likely cause of cupping. :ummm:

Learn something new every day.

While Under-Inflation certainly seems to be one cause of Cupping,
IMO, Over-inflation can also cause it.

"Can Overinflation Cause Cupping ?

Yes, it can but cupping can also have other causes. Over inflated tires can tend to bouce more, especially when combined with weak/worn shocks or struts. When tires bounce cupping can occur when the tires strike the road.
Cupping can also be caused by the tire/wheel assembly being out of balance (which can also cause the tires to bounce).Cupping is just one of several types unusual wear on tires."

I'm just stating what I learned through experience.
I had one Front Tire, a Michelin Macadam M50E that I ran at 39-40 PSI and it defintiley suffered from cupping, it gave me a high speed and low speed headshake/wobble.
I replaced the Bad Tire with a New M50E and instead ran 33 PSI as stated in the Manual and it Never occurred again,
so I would say that the Over-Inflation was the cause of that cupping since Nothing else was changed.
I have since stuck to the 33 PSI front - 36 PSI rear inflaltion levels and I have used a variety of tries and I have never suffered from High or Low Speed Wobble again.

 

[Saint]

I appreciate the insight Dman, i'll lower the pressure tonight to see if that helps. I bought the bike in hopes of doing some 1/4 mile track days for fun. really hoping I won't have to spend tons just to go fast, straight.

 

[Saint]

Ok, so I have good tire pressure, new front and rear tires on and balanced, did the bounce test, and have 12psi in the forks. For the last week everything felt great except for one time shifting from 4th to 5th caused a wobble to start. But this morning doing about 130kph in a bend the bike wobbled worse than I have ever experienced. does this mean it was just the speed and road conditions or did the tires and tightening of my head steering bearing not really fix my problem? Is the next step here progressive springs? I feel lucky to be alive right now

 

[donnelly317]

Wow that's not safe!! Try lowering the forks 2" in ur triple tree see if that helps. If ut does u might want to get lowering springs!

 

[Saint]

Sure I'll give it a shot tonight, I just dont understand how a 2007 with 6000 km could be this bad. It had one owner before me and a clear title, no signs of being dropped and I took every bolt I adjusted's virginity. I really like the bike otherwise I wouldnt be on here trying to fix this still. Anyways thanks again. It is worth noting that the bike felt better the day I ran no pressure in the forks, 12 psi feels real touchy even before a wobble starts. Lastly, when I washed the bike I noticed an excess amount of grease below the rings nuts that you tighten for the head steering bearing, could this mean the bearing lost its grease or is it normal for grease to build up there?

 

[DMAN999]

^ I wouldn't recommend raising the Forks up more than 1" in the Triple Tree.
The front fender might rub the Radiator if you raise them up 2".

I personally have mine raised 1/2" and I'm very happy with it's stabilty at Speed and while cornering.

I would definintely recommend you check out the Stearing Head Bearing, you might need to repack it.
I think there is some problem with your bike causing that wobble and you need to find it and correct it reather than mask it with alternative fixes.

As I stated before I have never had a problem with headshake/wobble on my Stock VMax (except once when I had a cupped front tire).
I only recently installed Progressive fork Springs and I'm even happier with the cornering ability now than I was with the mushy stock fork springs.

 

[donnelly317]

That's a good point and yea maybe check the bearing by removing the triple tree because just tightening it ain't gonna fix it if there bearing is fudged

 

[jfeagins]

Cornering. Wobble. Check your new tires for side-to-side run-out, especially the rear. Swing arm bearings properly tightened? ...thinking out loud...

 

[Saint]

Well the pinch bolt for the front axle and the front axle were both loose. Now I feel really lucky to be here. Tightend them up with blue locktite and pop goes the pinch bolt. 5 days til the dealer gets one in and I still gotta get the broken bolt out. not having a great day.

 

[donnelly317]

Torque man torque! Not to german specs ( goot n tight) lol can't u get one from hardware store be alot quicker if its just the pinch bolt! In not and u take front rim offight as well go tackle visually inspecting that head bearing if u got 5 days

 

[Saint]

yeah good idea, I went home at lunch to drop the forks 1" , which I did, thats when I noticed the pinch bolt was loose (and axle). I'll try the hardware store just not sure how long the bolt should be. And the hard part will be getting half the broken bolt out, im going to buy an EZ out drill kit after work and try that. I think I'll be asking for a torque wrench for my birthday lol

 

[donnelly317]

Hahahaha. Yea ill measure mine quick! Mines 56mm long or 2.23" and diameter is 7.8mm or. 310" threads I don't know because I don't have a metric thread gauge. Find the bolts that at 8mm diameter coarse thread and im sure ull get the right one! Remember don't get mixed up with lowering forks. U actually want to RAISE the forks in the triple tree to make the front lower putting more weight on front tire

 

[sdt354]

I got into a high sppeed wobbler 2 days ago at 120mph. I came out of it at about 75mph. A very unpleasant experience.It doesn't shake. I can let go of the bars and no issues.
My bearings are adjusted right. But, I feel a notch dead center in the head bearings, with the forks jacked up. I have the seal bearing set and am getting ready to tear into it .To be continued.
Steve

 

[donnelly317]

Dam!!!! Glad u rode it out!!! Good luck Steve!!

 

[Saint]

Yep the forks now stick up an inch over the top on both sides in effect lowering the bike a bit. Ill try to find the bolt before the dealer. I had my front wheel off for the tire swap and didnt feel anything strange other than a bit of pull on one side due to cables in the way. I hope those EZ out bolt removers work or else Im in big trouble. At least I figured out why they call it headshake... they arent talking about the bike.

 

[[email protected]]

That bolt should come out pretty easy.
I dont have the oe forks anymore but im pretty sure that bolt is 8mmx1.25. Shouldnt be too hard to find.

 

[donnelly317]

That bolt should come out pretty easy.
I dont have the oe forks anymore but im pretty sure that bolt is 8mmx1.25. Shouldnt be too hard to find.

yea metric doesnt usually come in many different thread pitches.. i know its 8mm and coarse thread so at the most there might be different thread pitches at the hardware store.. Just make sure you get stainless

 

[sdt354]

Dam!!!! Glad u rode it out!!! Good luck Steve!!

Thanks Bro, me too. I pulled her apart last night and the bottom race was all grooved up. Like I guesses, I was riding in a groove dead center. The berings still are together but worn and a little rusty. Todays project, swap the races and bearings out. The nothiness was really felt once I removed everything from the trees.