Lowering and Fork Wobble

[05calibusa]

I found a lot of threads related to this issue and it makes me wonder if changing the geometry of the setup has something to do with fork "wobble". This weekend I installed lowering links and dropped the rear using the middle hole on the dog bones. I already had handlebar risers on the bike, so I loosened the triple clamps and dropped the clamps down approx 3/4" on the forks. I also took some of the pre-load out of the rear spring. I took the bike out for a test run after getting everything tightened back up and noticed that I have fork wobble on deceleration. It is not bad, but I can tell when I let go of the bars. I did not have this problem before changing the setup. Any suggestions?

 

[H2447INTX]

take the bike to a good shop and have them set up your suspention , for you ,, that is why they are tuneable ,, it will make a day and night diff !


have had two busa lowered and i had no problem with woble of any kind !

also you can do the damper mod if you like ,, take your damper off drain the oil and refill with a heaver oil , some do 70-90 wt gear oil but realy you can play with it , add something a little heaver and see if it helps as well ,,, dont go to stiff couse then you get in to sow speed turning problems

any how hope this helps

 

[sixpack577]

take the bike to a good shop and have them set up your suspention , for you ,, that is why they are tuneable ,, it will make a day and night diff !


have had two busa lowered and i had no problem with woble of any kind !

also you can do the damper mod if you like ,, take your damper off drain the oil and refill with a heaver oil , some do 70-90 wt gear oil but realy you can play with it , add something a little heaver and see if it helps as well ,,, dont go to stiff couse then you get in to sow speed turning problems

any how hope this helps

+1, but the dampner will only mask the problem, correct the suspension first.

 

[05calibusa]

I would like to adjust the suspension myself. I am thinking that it's one of two issues:
1. I did not get equal height on the fork tubes
2. My preload adjustment is no good
Does anyone have know the correct settings on the rear shock for 1" drop and a 200lb rider?

 

[sixpack577]

I would like to adjust the suspension myself. I am thinking that it's one of two issues:
1. I did not get equal height on the fork tubes
2. My preload adjustment is no good
Does anyone have know the correct settings on the rear shock for 1" drop and a 200lb rider?

I do not, but remember, front and rear suspension work together. If one is perfect and the other is off, it will effect both. Go back to stock settings or completely counter clockwise, start over completely. If you don't have a service manual you can download one from this site.

 

[05calibusa]

I do not, but remember, front and rear suspension work together. If one is perfect and the other is off, it will effect both. Go back to stock settings or completely counter clockwise, start over completely. If you don't have a service manual you can download one from this site.

That makes sense, but I need to know if I did the right thing by loosening the pre-load on the spring because of the drop or if I should have just kept it at the original setting.

 

[sixpack577]

That makes sense, but I need to know if I did the right thing by loosening the pre-load on the spring because of the drop or if I should have just kept it at the original setting.

You have made a stock fork softer and are 200lbs. Most folks your weight have upgraded to stiffer springs anyway. Putting it back to where it was will be a good starting point.

 

[05calibusa]

You have made a stock fork softer and are 200lbs. Most folks your weight have upgraded to stiffer springs anyway. Putting it back to where it was will be a good starting point.

Thanks for your advice. I will try to go back to the original settings and start from there.

 

[sixpack577]

Thanks for your advice. I will try to go back to the original settings and start from there.

Sure, even though I really didn't answer your questions. PM Tufbusa, he's a trackcoach and can point you in the right direction with suspension.

 

[H2447INTX]

im not a bike tuner or suspention guy but when you lower the bike with dog bones your cangeing the geomitry of the suspention putting it at a diff angle with the longer dog bone so in turn that will aff it,,,,, but i had no problems even after lowering ,, i would not let off the pre load, i would leave it factory ,

back to my point you dont know how to set your suspention that is why i sugested you go to the shop

most will do it for next to nothign

we have a shop that will do it for 20 bucks

they tune it to fit you and your body weight !

i too am a tall 6' at a wopping 204 and i have no problem with the factory springs ,, you just need to set it up for you,,,,,,,,,,,,,,,,,,and gain this is the kicker


if you say you do not have your tubes even in the front that is the first and for most thing i would fix ,, and yeah it may fix your problem all together

basicly you have one side loaded more thean the other couse when you are rideing you have the bike up right ,and if they are not even in the tree then you are putting more presure on on side than the other

eather way i say shop you say DIYS well thats on you

ride safe !

 

[Tufbusa]

Geometry is most likely the culprit that creates the wobble but not necessarily.

You have changed your geometry and it can be a real beotch sometimes to work it out. I comes down to trial and error. I'm not a stretched and slammed suspension guru but there are a few things I can point out.

If your forks are uneven, that is not your problem. Your forks work as a single unit. If they are set at slightly different heights it simply means one spring is compressed a tad more than the other. Not a serious problem.

If you are going to lower your bike, lower it the same on both ends. This way you keep your stock geometry somewhat stable. The swingarm angle will be fookered up forever and there is no way to make it right but that's not a huge problem as long as you don't demand good handling characteristics.

Preload on either end does not stiffen or soften the suspension. Look at preload more as a ride height adjustment and you'll be better served. Back off the preload and it lowers the bike. Add preload and it raises the bike. Preload is a great adjustment for fine tuning if you know what you are doing.

When you decellerate your forks compress shortening the trail which is usually the culprit but if I read your post correctly you have lowered the rear more than the forks so this should not be a problem?

There is a great book on suspension tuning by Andrew Trevitt called "Sport Bike Suspension Tuning"! Buy it and read it from cover to cover multiple times and you'll have a much better handle on how to adjust your suspension. Sadly, it doesn't cover stretched and slammed units. I have never seen anything on how to set up a stretched and slammed suspension. But there could be something in print? If anyone knows of anything in print or video on setup for lowered bikes, please share.

Good Luck with your project! If the suspension was stock, I could give you some pointers but I have no experience in your particular situation!

 

[05calibusa]

Hey Tuf...thanks for chiming in on this issue. I read your other posts on suspension tuning and searched a few others, but a didn't find anything for lowered bikes. I am going to try adjusting one thing at a time to see if I can isolate the issue. The reason I didn't drop the front as much as the rear is that I am at the length limit on my brake line in front. I am going to get some longer lines, so I can get the same drop on the front and back. I will keep you all posted on what I find. There seems to be quite a few owners with lowered bikes, so maybe this will help someone else out.

 

[H2447INTX]

^^^^^^^^^^^^^^^^^^^^^^

seams like i have to post this in every "loweing bike" thread ,,,,,

if you have a gen2 busa the fork tubes get smaller under the bottome tree! ,, after 3/4 of an inch you will start to loose clamping surface ,, so i see all thes guys with the bke dropped like 1.5 in ,, to me that is sacrificeing looks for safety and not recamended in my op !

so if you have gen2 busa look at your fork tubes and you will see what i am saying is tru , then you can deside if loweing is what you really want to do !

 

[riccoh]

use a machinist ruler to make sure boths forks are at the same hight.. that is a normal problem when lowering the front suspension.