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Discussion Starter #1
Ok here goes nothing..

I recently had a set of michelin pilots 110/70/17 front 150/60/17 rear.. they tires look great on the bike Had them mounted and balanced at a shop. I then bolted everything back up, then had a vibration-headshake-shimmy in handle bars from 40 to 55 then it would stop and be fine. I looked up about the string thing from FOG, but i don't think i did it right. I tried several times. I first off aligned the wheel in the marks on the swingarm then went from there. Vibration wasn't effected for crap.
So I took the bike back off and down to the shop, they rebalanced this time around they used less weight in a different spot. Remounted today and went for a ride. Now there is no noticable shake upon acceleration(if it is there u don't notice it) (nothing noticed just crusing either) the only notice it when u leg go of the bars and decelerate (not that this would be a normal practice) but bike didn't do it before mounting these tires.

Please help with suggestions..

My only other choice is to just take it to the shop and let them try to figure it out ( and don't feel like paying a shitton of money to have that done)

Josh
 

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Did you check the ballbearings in the tripple tree ?

put the bike on it's center stand, grab the bottom of the front forks and push/pull to see if it's loose or if it wobbles.
 

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then I am puzzled too.. ???
 

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You haven't aligned the rear wheel properly. Read my string thing again and do it right.

FOG
 

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Discussion Starter #6
FOG..

You are right I prolly haven't... but I am not quite getting it.. I don't know why I can't visualize what exactly I should be doing versus what I am doing

Josh
 

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Discussion Starter #7
Also to add FOG, why did having the wheel being rebalanced make it less of a shake if it just being out of align?
 

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It might have been a balance issue from the start and you created another problem by trying to 'fix' it.. :-\
 

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Discussion Starter #9
yea that was my initial thought... but it didn't get worse when doing to string thing.. It did get better, now each time I have something done it just keeps getting better.. so i dunno
 

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Discussion Starter #10
ok this is the part of the whole thing i am not understanding..

Now turn the handle bars to make the front tire parallel to the strings.

Now measure the space from the string to the front wheel rim on both sides. Both measurements should be the same w/in 1/16”

If they are you’re done.

i must be taking measurements at the wrong place
 

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OK you got to the easiest part. Turn the wheel till is parallel to the strings. now measure from a string to the wheel rim. then compare that measurement to the first.
Simple yes?

FOG
 

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Discussion Starter #12
so it doesn't matter where on the rim i take the measure ment.. as long as it is the same spot on both sides?
 

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Closest to the bottom is best
fog
 

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Discussion Starter #14
Ok I got the whole string thing now..

Bike is straight.. Both measurements are less then 1/16th different so that is all good. But after all this stuff I decided to spin my front and guess what. I think all and all it was just a balance issue.

The tire will spin freely then slow and stop then back up... crap it isn't supposed to do that right? It should just spin and slowly stop. And I can noticve a slight wobble maybe a 1/16th of an inch as it is spinning. So I went and got some weights and I am going to try to balance it myself, cuz I have had it down to the shop and they said it was all good this time.. last time I take it there..
 

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Is it possible that the front rim is bent ? <= getting this from the wobble you described ???
 

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Discussion Starter #16
I don't think the rim is bent unless they would have a way of bending it at the shop.. and i took the wheel into them.. because there was less then 1/2oz of weight on the rim with the factory tires and I have never hit anything or potholes anything..

so i think i am going to remove the front and try to balance it myself tomorrow morning.. and see what happens.. if that doesn't work I give up.. let a professional work on it
 

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We had a Plymouth van that had weird wobbles felt in the steering wheel.
Turned out a belt in the tire had broken & the tred has a sideways warp that caused it.

I do not know if anything similar can occur w/ motorcycle tires, radial or otherwise.
 

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With respect to the "string thing" method of aligning front with rear, I've been assuming that it is necessary to ensure that the width between the strings passing the front tire are exactly equal to the diameter of the outer edge of the rear tire. I cut a little piece of wood with slots to this dimension and put it between the strings, i.e. a spacer. I just don't trust my eyes to ensure that the strings are exactly aligned front to back. The first time I used this method I placed the spacer behind the front tire. Am I thinking about this the right way? Should the spacer be placed in front of the front tire so I'm assured that the space between the strings is exactly equal to the width of the outer edge of the rear tire as it passes the front tire?

Please no flaming. I'm just a frustrated rider with a vibration/wobble problem very similar to the one described in this thread. ;)

p.s. I've done the string thing setup three times and each time I think I have got cured based on measurements, the vibration/wobble persists. I understand that practice makes perfect.
 

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Toss the spacer bar as far as you can.
The whole point is that the strings pick up the rear and front edge of the rear tire and extent that line un encumbered to the front. Once the string is fixed to the tire and a movable stanchion get down on it's level and eyeball the string as you move the stanchion a bit side to side till you see the string just Kiss the front edge of the rear tire in a place Identical to where it's wrapped around the back edge (like not in a tread grove ).
DO this on both sides and be sure the strings touch nothing else.
Even if the strings are a tiny bit out of parallel( they shouldn't be) the Idea is to show where the back wheel is going.

And the whole point is to set the rear tire chain adjustments till the path of the rear wheel exactly co insides with the steering head bearings as defined by the front tire.

It should go without saying that if you need to move the rear wheel, the strings must be reset.

With some really shagged race tires where the edge was not even, I glued two identical blocks to the rim to move the string off the tire.

FOG
 

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Thanks Bill. I'll set it up again. Since changing the tires, it just bothers me that I haven't been able to get rid of the shakes during deceleration between 50 mph and 40 mph.

Mike
 
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