Tank-slapper at 40 mph

[coffee_brake]

Just picked up an '01 pretty well stock, full well knowing the handling issues of this bike. But I wasn't expecting the front end to wobble into a tank-slapper while decellerating at 42 mph! The front tire is some cheapie from the dealership but it is new. No cupping on it and it's inflated to spec.

I haven't done the Furbur thing yet because I wasn't sure where to source the washer, just got the bike last week.

Only on decelleration (i.e. the front suspension is loaded) and only at 42 mph, if I'm holding on with just the right hand and slightly relax my grip, the bars wobble, then oscillate further and faster until I have to grab on with both hands or lose control. Hit the throttle, though, (i.e. unload the front suspension) and it steps right back into line.

I've searched here and maybe I missed some glaringly obvious posts about this. I'll re-torque the steering stem this weekend, but my question: does the washer have to be aluminum? Is it readily available at the hardware store? Can I pull out my trusty Dremmel and modify a big steel washer? Are the dimensions specific?

Many thanks for any info, and again, if I missed obvious posts, sorry. Just learning my way around still!

 

[dannymax]

Jack the front end up and swing it to either side, see how hard it hits the stops. You want it to hit the stops with very little to no bounce.

Don't be too concerned about actual torque #'s, it varies due to different tolerances and wear.

I would try the above before doing any washer fix, there's many folks, me among them, who feel the alum washer does nothing at all. The issue is all in the bearings.

I had this exact problem, snugged up the steering head bearings, dropped the forks in the trees 3/4" and it handles like a new one.

Well...........a new one without a wobble!! :biglaugh:

Good luck!

 

[one2dmax]

Yep, the steering head bearings are too loose.

Sean

 

[coffee_brake]

Thanks folks, I really, really like the cheap easy fixes!

 

[KJShover]

Yup +2, loose bearings.

My '07 was solid as a rock until I brought up the front wheel a few times, I wasn't putting it back down in the kindest of fashon and loosend things up a bit.

re-torquing did the trick.

 

[naughtyG]

In my case (an '86 with 40k on the clock), tightening the bearings and doing the furbur fix made no difference at all (I had a real bad high speed wobble at 115+mph).

In the end replacing the bearings altogether was what fixed it, as they were totally shot. It's also impossible to feel how bad they really are until you take off the wheel and forks - all that weight gives you a false reading - making you believe they're fine when they're not.

Having said that, after a 1000 miles, when I let go of the bars at slow speed it all starts shaking as well so I thinking a little tightening's in order. I took the metal washer off and went back to the original rubber item btw - it seems the Furbur washer is nothing more than a band-aid for bearings on their way out!

Just my 2 cents..

 

[coffee_brake]

Noted, thank you again. I almost forgot it has a center stand, I can go re-torque it right now (and not use the lift at work).... if my husband will be so kind as to sit on the bitch seat for 5 minutes....:hihi:


Nah, he's a helluva rider, I gotta cut him some slack, even though I have the fastest bike in the stable now!


So first the fallaway test, and then if it hits the stops hard, re-torque it. I have my Clymers now, my dinosaur computer crashes when I try to open the shop manual online. So I have the torque value.

Many, many thanks everybody!

 

[naughtyG]

The torque value in the manual is on the really low side. I torqued mine slightly higher when I replaced the bearings, and it's still a little loose so I'm gonna tighten it again.

Also, those castle nuts have a weird shape, so if you want to actually use a torque wrench you'll have to make a tool by grinding a BIG socket down to fit into the castle nut's grooves.

The easier way, if you can get hubby on that bitch seat for long enough (lol) is as follows:

- remove the top nut on the triple tree (get hubby to help - even if only to hold the bike - this one is bloody tight)

- using a blunt tool and a hammer, tighten both castle nuts together (there's a washer holding them aligned) while repeating the bounce test.

- from straight up with the front wheel off the ground, just a little push on the bars should be enough to make them fall on either side, but they should just hit the stops without bouncing off.

- don't go too tight, or you'll develop a weave at low speeds where the bike won't wanna go in a straight line without constant correction.

My advice tho, as soon as you can, take the front wheel, brakes, fender and forks off to get a proper feel of the state of your head bearings. It's really not that hard to do, and the only way to positively tell if they need replacing yet or not. Any roughness can be easily felt once all the weight is off them..

Hope this helps - it drove me crazy long enough!

 

[coffee_brake]

Yes, that does help....after pulling the front end apart and finding I have no way to re-torque the nut. I don't have any disposable sockets, I will try adjusting to the fallaway standard.
The rubber ring between the washers was smooshed into an egg shape.
The steering head will sit in the middle with the wheel off the ground, but a nudge sends it crashing to the fork stops in either direction.

Hubby behaved admirably and even put it on the center stand for me, as I was wearing my fuzzy slippers and they don't have much for soles. :in love:


Anyway, the info here is great, thank you again.

 

[dannymax]

Coffee Break-How many miles on your '01?

 

[coffee_brake]

Oh, 31k miles, I suppose it might be due.

This morning I took off the wheel and fender and there is NOTHING impeding the front end except the forks still in the lower tree.

I have not done this fallaway test before and I'm not sure what I should be feeling/seeing.

There is no up/down play in the front end, but it was loose. It would sit in the middle but fall to either side very hard. So I tightened the nut (the tool that adjusts the shocks on my Honda actually moves this nut easily, but no way to torque). Every 1/4 turn I did the test again. Now it sticks in the middle and about halfway through each side's radius, it will stay where I put it. Then, in the second half of the radius, it will fall to the stops.

Is that too tight? At this setting, I CAN feel the bearing but ONLY at the last bit before the stops, no notching in the middle. That's the first place that it notches, isn't it? The middle? I don't feel notching in the middle, but if I tighten the nut pretty tight, I can feel something near the stops.
If it is adjusted looser, where it falls hard to the stops, I cannot feel any notching at all.

Too many words. Sorry. I know this is a technique best learned by doing, I just don't have a good way to describe what I see on this bike.

 

[dannymax]

It sounds like you might be due for new steering head bearings.

The swing should be smooth through the whole radius and simply swing slower as you tighten down the nuts.

Don't be too concerned about actual torque numbers, IMO there's just too many variables to set an absolute torque value for all v max's. It's a "how it feels" type of adjustment.

NaughtyG will chime in here soon I expect, he replaced just about all the bearings on his bike and will have some helpful tips.

 

[Noxx72]

My '01 has the same violent wobble at 40mph decel, especially under engine braking. I haven't done anything to fix it yet, because it seems like I'm always tearing apart something else, but I'll give re-torquing it a whack this weekend.

 

[gamorg02]

CB, maybe take a video of it and post it on youtube then post a link here... i bet if people could see what you are talking about it would help!

 

[naughtyG]

I can't recommend new bearings enough. At 31k miles you're pretty close to the 37k my '86 had when I got it, and my bearings were totally dead. I think it has a lot to do with the weight of the bike.
There are instructions here for replacing those bearings, but be warned - it's a real pain in the arse.. Popping the top bearing and race out is not so bad, but the bottom race is difficult unless you have arc welding equipment. If not, like here, the only way is to cut the old race out with a dremel tool or equivalent, and you have to be ultra-careful not to damage the frame. The same is true for popping the lower bearing off the lower triple tree.

But, having tightened them a bit, have you tried riding it yet?

 

[coffee_brake]

I didn't ride it yet because it took hours to pull it apart, and if the bearings are indeed bad, then I didn't want to put it all back together, then pull it back apart again. I was hoping folks here would have more knowledge, and they do. I work in a motorcycle service shop that is too busy right now for me to be bringing in my own bikes, so I'm yanking apart machines all day just to come home and yank apart my machine all night, except my tools at home are limited. (I'm just a bike breaker, not a mechanic!)

Meh, no complaints, I like my job.

OK I should get in new bearings early next week. I don't think my dinosaur camera will take a decent video, but if it does I'll try to post it.

Are AllBalls bearings decent? I've used their wheel bearings before with no problem, but never on the steering head.

I will have to cut out the old races with my Dremmel. Is it two cuts, 180 degrees apart? Do I need to buy a drift pin? I read the how-to, I'm going to try but I'm not sure if I can do it. But at least I'll try first....

 

[gamorg02]

whats the price difference vs oem?

 

[naughtyG]

I would go with OEM bearings - well worth it on such a high-wear item. I made the mistake to go for knock-offs cos they were cheaper, and ended up having to buy an OEM one at the high price just to finish the job. Duh! learned my lesson the expensive way.. :bang head:

Call Gary McCoy @ Mondak Motorsports on 406-433 6635 and mention this vmaxforum - he gives us 20% on all Yamaha parts, and that's the best deal anywhere. Both bearings is just about $50. :eusa_dance:

For the cut, it's debatable. The way it's shown in the how to is best IMO, even if it takes a while. You REALLY don't wanna damage your frame - just grind the bearing race until you can pop it off. I went for a cut perpendicular to the race using a thin cutting wheel, and ended up cutting a little into the frame :damn angry: - not good.

THE best way is most definitely a bead of welding on the race itself - as it cools down it should just fall out. Remember heat and cold are your allies when working on metal, it expands when hot and contracts when cold. So hot frame + cold race can be a great help.

But make sure to inspect your bearings beforehand - if they look like mine you most definitely wanna replace them!

See my old ones here..
http://www.vmaxforum.net/showthread.php?t=5550&highlight=head+bearings
Also, good instructions here..
http://www.vmaxforum.net/showthread.php?t=3314&highlight=head+bearings
and the ones I mostly followed here..
http://www.vmaxforum.net/showthread.php?t=5086&highlight=head+bearings

 

[coffee_brake]

Oh, wonderful, very good links! I'm as ready as I'm going to be.
I have replaced the head bearings on the Harley that I traded for this bike ('03 FXDX) and also on my project '82 KZ440 basket case (now a rolling chassis with fresh pistons and rings), and they seemed similar, especially the difficult parts! But on these other two machines, it was very clear that the bearings were gone, I could feel the notch at the center of the steering. This Max, however, doesn't have a notch in the middle, but maybe a little at each end.

Gamorg, the AllsBalls brand is about $30, I've already ordered them. I haven't run their head bearings (although I have installed two sets of them) but the wheel bearings have always been good. I'll give 'em a try.

I guess I can go try to get the old bearings and races out, while I wait on the new ones....I wanna ride my new bike!

 

[naughtyG]

When you order the new bearings, make sure the lower one is of the 'sealed bearing' kind.

If not (which was my problem with the Pyramid Parts ones I first got), the lower bearing will be open to the elements and self-destruct in a pretty short time.. :confused2: