New vmax owner headshake

[Saint]

Hey guys, great site here. My dad had a 98 and I really liked it so I traded my ninja for a 2007 vmax with 6000kms. Very comfy, very fast. the bike runs really well except at 100mph I start getting the front end wobble, so I let off the throttle and as she slows down she stabilizes. I checked tire psi, tightend head steering bearing as per bounce test, and drained all pressure from my forks so there wouldnt be an uneven amount. I still have the same wobble give or take 5mph, and it seems the harder I accelerate the sooner it shakes. I love the bike but I need to solve this. I'm wondering if the next step should be to replace my tires? (front laser ,rear 880??) or if I should replace the bearing first. Sorry for the wall of text, and would someone get this damn monkey off my back?:biglaugh:

 

[Rhoy Carter]

Im not sure it is a good idea to lose the air pressure with stock springs and you can also check and make sure the swing arm bearings are tourqed right. A bad front tire can also cause problems. I run 38 psi in front tire and 40 psi in the rear.

 

[Saint]

ok well I have a hand pump and tried about 5 psi in each fork and thought it made the wobble worse, maybe they were too uneven? the front tire is pretty worn down the middle, I dont think the last owner even made a turn. my tires are at 36 front 39 rear since the frame sticker recommends 35 39. I'll keep messing with my pressures and bearing tightness but 3 nights of different settings hasn't made any difference.

 

[srk468]

Hard to believe with that few miles that the head bearing would actually be shot, I'd definitely replace the fork springs with progressive ones though but make sure you get Yamaha seals because the aftermarket ones suck. I'd also at least have the balance checked on the front tire but a new tire isn't going to hurt either..

Sent from my ADR6400L using Tapatalk 2

 

[Saint]

do the progressives come with seals? playing with forks is new to me this is my second bike. If I decide to order new tires would I be better off with front and rear 880s? or laser front 880 rear?

 

[donnelly317]

http://vmaxforum.net/showthread.php?t=3827&highlight=stem+bearing

Do the tightening check. Should fix it. I think I read the torque from factory was wrong??

 

[donnelly317]

Maybe you already did this?? Haha didn't read the full post

 

[Rhoy Carter]

I have had good luck with 880 front and rear and try 12 to 14 psi in the forks.

 

[Rhoy Carter]

When installing progressive springs you do not need to replace the seals unless they are leaking and the progressove springs do not use air pressure.

 

[Saint]

I've tightend the head steering bearing about 5 times the last 3 nights with no improvement. The worst the bike felt was with 5 psi in the forks, 39 front and rear tires, it wobbled at about 80mph. so I put my tire psi to 36 and 39, drained the fork psi, and I'm back to where I started with the wobble at 100mph

 

[Saint]

ok I'll boost the forks tonight to 12 psi and if that doesnt work Im buying springs and tires.. will keep you posted. So many threads about this on goggle but hardly any resolutions

 

[ninjaneer]

So many threads about this on goggle but hardly any resolutions

The reason is because there isn't a definitive solution. What works for some may help others, but sometimes doesn't totally eliminate the issue. There are things that you can do to mitigate the problem, like proper head bearing torque, proper tire pressure, fork setup, etc. just like you have done and what others have suggested. No one can say for sure that the wobble exist because of a specific thing or item, because, for example, things like tightening down the bearing, although it may have been "it" for some, isn't always "it" for others (as you can now attest to)

Good luck!

 

[donnelly317]

With the hard you accelerated the sooner it happens makes it sound like you don't have enough weight on front tire.. crotch rockets have most of the weight on the front tire. What size tires are you running? Might be your front tire is bigger than rear tire. Stock the front slightly bigger than rear.

http://www.miata.net/cgi-bin/tirescgi

As you accelerated even more weight is removed from front tire.. id try raising your forks 2" and see if that helps.. should make your front lower putting more weight on front tire.. its not a permanent fix tho.. is it helps it id plan on doing 2" lowering springs in your forks.. just a thought

 

[donnelly317]

If you have 110/90-18 on front when you buy new tires go with 110/80-18 this is a smaller diameter will make the bike more front heavy I believe

http://www.miata.net/cgi-bin/tirescgi

 

[srk468]

Good idea about lowering it through the trees like that but only go 1" max because the fender can hit the radiator... Also isn't the 110/80-18 a radial? If your going to radials in the rear that's a great idea but don't mix and match radials and biasplys because it won't be good. Good luck bud!

Sent from my ADR6400L using Tapatalk 2

 

[donnelly317]

They do make bias in 110/80-18 Metzler me880 http://www.ebay.com/itm/221044761516?redirect=mobile

But if your buying new tires why wouldn't you go with radials?? Lol I do believe they make radials that fit the 15" rear tire don't they?

 

[jfeagins]

My money is on a bad back tire!​

IMO Tires/wheels cause wobbles. Everything else is just making sure the wobble will be minimized when/if it happens. Bad wheel bearing(s) and/or head bearings could also contribute to a slight wobble, or more likely some wandering around when hitting unevenness in the roadway.


I've had the dreaded wobble pop up a number of times on my 85 over all these years, and each and every time it's happened, all I needed to do was install a new, well balanced back tire to get rid of it. It's been my observation that biased ply tires are more prone to causing this issue, and I run the OEM biased ply Dunlop on mine. Way back when, I tried one of the OEM Bridgestone Exedra's, and as I recall, it too, started causing a slight wobble at high speeds before it's life span ran out.

If you over-tighten that head bearing, you can get rid of even the worst wobble caused by a tire, but you'll most likely have a low-speed weave, and then end up with a flat spot on the bearings.

Again, my money is on a bad BACK tire.​

my two cents. Please keep the change.

 

[donnelly317]

Did you read on this?

http://vmaxforum.net/showthread.php?t=167

 

[donnelly317]

My money is on a bad back tire!​

IMO Tires/wheels cause wobbles. Everything else is just making sure the wobble will be minimized when/if it happens. Bad wheel bearing(s) and/or head bearings could also contribute to a slight wobble, or more likely some wandering around when hitting unevenness in the roadway.


I've had the dreaded wobble pop up a number of times on my 85 over all these years, and each and every time it's happened, all I needed to do was install a new, well balanced back tire to get rid of it. It's been my observation that biased ply tires are more prone to causing this issue, and I run the OEM biased ply Dunlop on mine. Way back when, I tried one of the OEM Bridgestone Exedra's, and as I recall, it too, started causing a slight wobble at high speeds before it's life span ran out.

If you over-tighten that head bearing, you can get rid of even the worst wobble caused by a tire, but you'll most likely have a low-speed weave, and then end up with a flat spot on the bearings.

Again, my money is on a bad BACK tire.​

my two cents. Please keep the change.

Wait you may have solved my problem here too!! I order wrong size tires for my bike. I got me880 both front and rear. Rear is 210/40-18 and front 110/90-18. Making front bigger than rear. But my point here is that the shop couldn't balance my rear tire being a 18x6 kosman it was too wide.. so if my rear is off balance it will cause a wobble?? I only get a wobble around 45 mph if I take my hands off handle bars.. I guess I should get those balancing beads for my rear tire huh?

I just put the tires on my bike didn't feel like shipping them back because im getting 17" kosmanss in the fall :eusa_dance:

 

[one2dmax]

I was going to mention to not overlook the rear tire and settings since that is where a lot of the wobble can emanate from! Jim beat me to it!

Sean