lower fork shimmy

[gamorg02]

so i was riding the other day and noticed on bigger bumps i could see the lower part of my front axle near the forks shimmy back and forth. When i say back and forth i mean like the axle is moving toward the oil filter. not much, probably less than 1/8". i took the hawk out today to see if it acts similarly and only under engine bogging (like give it decent throttle at 1.5k rpms), it would really act similarly.

Is it an opitcal illusion or do you guys see the same thing?

NO clunking, head shakes or any feeling of the shimmy just if i watch it.

i'm going to jack the front end up at some point soon here to make sure it feels tight but i gotta imagine if it was actually something i'd feel that, ie that loose of bearings, or worn inner fork bushings.

its almost like whole front fork assembly, on compression are bending slightly.

thoughts? anyone else notice this or take a look?

 

[Traumahawk]

I wonder if its steering head bearings? The yamaha way of testing those is to pull and push forward and backward on the lower forks. and see if they are loose.

 

[tugla]

I've seen flex in mine.....little disconcerning .....I just don't look at it.think due to mass of wheel and design of front end its the way it is......both bikes do it....hope its normal lol

 

[gamorg02]

I wonder if its steering head bearings? The yamaha way of testing those is to pull and push forward and backward on the lower forks. and see if they are loose.

yea i'll check that i just think it would accompany a big headshake too. i have a damper but i can't even produce a headshake usually if i hit the handlebars.

I've seen flex in mine.....little disconcerning .....I just don't look at it.think due to mass of wheel and design of front end its the way it is......both bikes do it....hope its normal lol

so you've seen it too then. i think you're right. heavy bike, bigger rider, flex in the system.

part of the reason i think USD forks are better. i don't feel a loss of grip or breaking.

and i sure dont' notice it stopped if i grab the brake and push down. smooth as can be.

my suspension is pretty firmed up though. progressive and a bit of preload, lowered 1" internally.

 

[tugla]

ya man I see it...scary looking....also hard braking hitting slight bumbs on road....scary shit man.....

nice set of inverted forks and new style tripple tree I'm sure helps that a bit

 

[Traumahawk]

Let us know what you find...my front end is almost like yours...just no steering dampner.

 

[gamorg02]

jacked the front end up, hard to get the bike 100% secure but any movement i could find in the front end was the whole bike moving, so its pretty solid. i think its just a lot of bike and rider and forks that aren't quick up to the task at times. maybe why the stock springs are so weak?

 

[one2dmax]

I believe the small shaking and also movement front to back is pretty normal.

 

[gamorg02]

I believe the small shaking and also movement front to back is pretty normal.

what do you attribute it to?

 

[one2dmax]

Pure flex from the road stresses. Excessive amounts can be from work fork slides (on the steel tubes on the lower area and pressed into the fork legs on the upper).

 

[gamorg02]

Pure flex from the road stresses. Excessive amounts can be from work fork slides (on the steel tubes on the lower area and pressed into the fork legs on the upper).

makes sense. mine looked good when i did my seals a few years bakc.

i imagine stiffer springs don't help with some preload.


also if i'm thinking about it right the bushings are probably more secure than the seals, so it might also be slight flex in the seals eh?

 

[maxcruiser]

I noticed the same thing a few years ago on mine and figured that due to the fork design, all that weight (wheel, brakes, etc...) was causing stress to the fork tubes.

After alot of research on the subject, I worked with Jedi to create that fork brace that I have on my bike now. It does take away alot of that front/rear flex.

Mike

 

[gamorg02]

I noticed the same thing a few years ago on mine and figured that due to the fork design, all that weight (wheel, brakes, etc...) was causing stress to the fork tubes.

After alot of research on the subject, I worked with Jedi to create that fork brace that I have on my bike now. It does take away alot of that front/rear flex.

Mike

I could see the upper brace helping but not the fork brace that goes between the two lower forks, and bolts to the fender.

seems that wouldn't help those torsional forces. is that correct?

 

[donnelly317]

Like other said mine does the same

Sent from my SCH-I535 using Tapatalk 2

 

[maxcruiser]

I could see the upper brace helping but not the fork brace that goes between the two lower forks, and bolts to the fender.

seems that wouldn't help those torsional forces. is that correct?

Yes sir, the upper brace was the one that I was referring to.

Mike

 

[gamorg02]

Yes sir, the upper brace was the one that I was referring to.

Mike

we're on the same page, so did you notice any 'feel' with just the change to that brace or just no more shimmy, but felt the same?

 

[maxcruiser]

we're on the same page, so did you notice any 'feel' with just the change to that brace or just no more shimmy, but felt the same?

I did. The front end feels "stiffer" than without the brace. i wouldn't say that it is as stiff as inverted front forks, but definitely better than stock.

Mike

 

[maxcruiser]

Here's some articles that I looked at awhile back that gives a good explanation to frame, swing arm and front fork flex.

This is also the first time that I seen the "Carl's Clamp" set up. The brace that Jedi designed and produced is definitely a big improvement.

http://www.awol.co.za/WobblesWeavesShaking.htm

Mike

 

[gamorg02]

Here's some articles that I looked at awhile back that gives a good explanation to frame, swing arm and front fork flex.

This is also the first time that I seen the "Carl's Clamp" set up. The brace that Jedi designed and produced is definitely a big improvement.

http://www.awol.co.za/WobblesWeavesShaking.htm

Mike

very cool. i wonder if jedi would make more of his setup, or just those clamps this guy has.

 

[CaptainKyle]

All bikes have a little flex in the front you should stand back & watch some bikes on the dyno or when they put there front end up against a wall & do a burn out. You might be surprised what you see.