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If only it had 6th gear..
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Discussion Starter #1 (Edited)
Hey guys. Got a new front tire put on a couple of weeks ago and just this weekend got to play a little on the highway. Somewhere between 95 and 100 I get an interment wobble, particularly after a strong cross wind or road surface change/blemish. I don't ride at those speeds all the time but I'm pretty sure I'd have remembered it doing this before with the old tire. The newbie balanced out fine and the rim is true, and other than this there isn't anything else going on other than the regular vibrations. I put the tire back on myself so I'm going to check the axle bolt, bearings, trees, side play, all the regulars but I'm putting it out here to see if anyone else has had this happen to them. Again, it isn't constant but comes unexpectedly, which is worse. Doesn't last long but just feels like the front end is sloppy. If I find anything that rears it's ugly head I'll update just so other's can have the info. Wasn't too happy when it first happened :wow:.

I know some of you run the Super Brace. Are you happy with it? I went to the site but couldn't find our model on there. Was probably me though :(

Also,what about air pressure in the forks? I've never messed with'em and I haven't seen evidence of leaking but uneven pressure? (Just thinking out loud....uh....well, on screen.)

Thanks to all,
dave
 

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I would re check the balance, and check the steering head bearings for play. Vulcans rake is generous enough that getting high speed wobbles is usually do to something worn, or loose. Occasionally you can lose a wheel weight, but checking the forks is a good idea too.

I had a Superbrace, and liked it.... But you need to find out what is wrong with the bike before installing one. They may have removed the VN750 off their list, but a call to them will find if they still make them.
 

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If only it had 6th gear..
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Discussion Starter #3
Thanks Knifemaker. Good advise, and I will look into the balancing as well as the other items, I was kidding myself that it was the wind but normally this bike is fairly stable, for what it is, at high speed. Then I was thinking maybe there's a problem with one of the fork springs but I would think that would show itself at lower speeds and cornering which still feel the same as always.
Dave
 

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If only it had 6th gear..
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Discussion Starter #5

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I put the tire back on myself ...
I guess you made sure the bead of the tire seated evenly around the rim on both sides?
You lined up the balance mark of the tire with the valve stem, right?
Checked directional mounting with rotation?

Might be worth a double check ...
 

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Thank you Gordon, that's great. Do you have one on yours?
No, I don`t have one yet. Southern Alberta praries have roads so straight and flat that I have to ride at least a hundred miles to find any decent twisties. I will decide if I need a superbrace after I rack up a few thousand miles on the bike. :smiley_th It needs lots of other stuff first.
 

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If only it had 6th gear..
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Discussion Starter #8
I guess you made sure the bead of the tire seated evenly around the rim on both sides?
You lined up the balance mark of the tire with the valve stem, right?
Checked directional mounting with rotation?

Might be worth a double check ...
sorry, I should have said put the wheel back on. I had a shop mount and balance the tire. The arrow is correct but I'll look at the bead to see if its even and the balance mark too. Thanks for the suggestions.

I know what you mean Gordon. There are other things that are more important on mine also. Probably look at one for next season since it's really not a necessity.
 

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I mounted and balanced (using Marc Parnes balancer) both tires and have had it up to 100 MPH w/no issues. I also have a Superbrace...no difference running straight, but decidedly firmer in the twists.
I agree w/others...prolly needs to be re-balanced. Suggest removing both front brakes...set up on center stand...have someone sit in seat..raising front wheel off ground. Front wheel should rotate freely and stay put (not rotate AT ALL) when you let go. Turn wheel 1/4 turn, try again and so on. Not the best test, but a good (cheap) starting point.
 

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Ride On or Dynabeads will fine tune the balance. I like Ride On as it helps prevent flats.
 

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If only it had 6th gear..
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Discussion Starter #11
Thanks guys, I appreciate the input. Voip Doc I'll try that test. Flitecontrol, I'm pretty sure I bought some of that ride on. Now to find it though.
 

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Check the bearings in the triple tree. Also check out the rear wheel bearings and swig arm bearings. Since you don't experience wobble until high speeds one would suspect the front end to be ok.
Bronson
 

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If only it had 6th gear..
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Discussion Starter #13
Thanks Bronson. Will do.
 

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If only it had 6th gear..
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Discussion Starter #14
Well, I checked out everything related to wheels/suspension and haven't found anything wrong except the dust seals on the forks. There may be some oil loss making the front tolerances uneven but it hasn't done that since thankfully. Maybe it was the wind hitting the shield a certain way that one time. The bike has a personality though. The other day at around 90 it jumps from 5th to 4th. Wasn't very nice to do that. I think maybe I just didn't have 5th fully meshed (I'm hoping) since I try not to slam on that shifter tie-rod. Anyone else have that happen. My Suz did it once in a while when you romped on it I think between 3rd and 4th but that was another life ago and much as I loved that bike it was a polished turd... and I polished it, lol.
 

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A balance issue will have a vibration, not so much a wobble. A wobble is usually indicative of loose bearings, axle bolts or forks. A balance issue will come on before 100 MPH.
How does it track when you are riding on an uneven road?
Mine was bad till I put on a new set of tires, and now it's gone.
Check to make sure your forks are even.
 

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GreatDays
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I was having a scary sloppiness in my front end (1993 Vulcan 750) and in the process of working on my front calipers -- the front axle bolt was finger-loose, ie. I unscrewed the front axle bolt the rest of the way off the axle with my fingers. I just bought my used Vulcan 750 couple weeks back and the prior owner did something upfront and forgot to re-torque the front axle nut -- my shop manual says 43 ft-lbs on the torque wrench and today after re-mounting my front calipers that's what I torqued the axle nut at.

I was riding around hitting 60mph the past few days with 2 problems -- a dragging front brake and a finger-loose front axle nut. I'm thinking the shimmy/looseness was being cause by the left side fork leg not being tight on the front wheel, under a turning load the left fork very slightly pulling away, sliding outward on the axle, away from the front wheel. I'm just happy there's a vertical axle retaining screw on the other fork leg or maybe the wobble would have led to loss of control.

If you put the bike on the main centerstand then lodge something under the front of the engine/frame to pick the front wheel off the ground -- then sit in front of the bike and facing the rear -- and hold the bottom of the 2 fork tubes in each hand -- try to push/pull/push etc. ie. 'rock' the forks backward and forward -- they shouldn't move.

The entire procedure for checking the front end for this kind of problem is in the factory shop manual.

Good luck, I know you were just working on the front wheel thought I'd throw in the axle nut -- it will cause a loose front end feeling.
 

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If only it had 6th gear..
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Discussion Starter #17
Thanks guys. Bill - It tracks really well on the crappy roads up here in Ma. I agree about the balance thing not really causing a wobble and that it would be evident before that high of a speed, and it seems that the mech did a good job balancing. The front donut is only a couple months old. I did check the bearings/axle when I had the tire done and they checked out good. No end play or axle grooving.

Carl - Good point about checking the forks that way. I have over the stuff I mentioned, but I didn't think of checking for play in the fork tubes themselves where the halves meet. Was looking looking higher and lower than that area :doh: at the wheel and axle, triple tree, rear shocks, swing arm etc. so thanks for calling that to my attention.
 

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Everything else has been discussed. I noticed you have a windshield. Take that off and see what happens. I had a windshield that caused SEVERE headshake at 75-80 mph. Balance will cause a shake, but not a wobble. I have always spin balanced my tires by hand until they were perfect, no matter how long it took. I have Ride-On in my tires too, but only to prevent flats, not for balance.

There may also simply be something wrong with the tire. The plies may be off a bit. Defective tires are becoming more and more common. If all else fails, replace the tire.
 
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