Author Topic: 08 handling issues (Read 26137 times) Tweet

gjp1300 · « **on:** September 13, 2008, 03:06:37 PM »

I've owned three Gen1 busas 2000,01,05,stone stock to piped,between the 3 bikes put about 75,000 miles on them and never had to make any drastic suspension changes to go fast through corners,especially high speed sweepers,the Gen1 was stone stable,I could flat out fly on the Gen1 and had total confidence knowing the bike would do what I wanted it to.My 08 handles like shit at high speeds,I hit a high speed sweeper at 130 to 140 and the front end starts to weeve back and forth almost like a wollow,scares the shit out of me and it pisses me off at the same time,I ran the stock settings it was terrible,I drove the front preloads down to the second line and bumped the compression up 2 clicks harder,the rear I went 1 click harder on the compression,seems to have improved a bit but it still has the same issue,it just doesnt handle like my Gen1.I'm chasing my tail on this one,the 08 has stiffer springs up front,they didn't change anything else but body work,is it an aerodynamics issue,is it just my bike or has anybody else experianced this also.I jump back on my buds Gen1 and I'm right at home,I get on the highway and fly and don't have to worry about the bike weeving or wollowing when I hit a sweeper at 140 hangin off the bike,it's depressing cause I bought a new busa thats faster in a straight line,it's piped and it flat out flies,but I can't drive it the way I want through corners,it sucks.I'm starting to think it's a aerodynamics issue cause at lower speeds it pretty much feels like my Gen1 but at high speeds it's all over the place up front,is anybody else having this issue or is it just my bandle like.Need some input from poeple that really push thier 08 busa through corners at high speeds and rode thier Gen1 the same way,thanks.

Quijinn · « **Reply #1 on:** September 13, 2008, 08:22:00 PM »

Sounds like you are used the softer suspention settings, might want to take some preload out of it and see how it does. Also setting the rear sag will help alot, you might be getting some rocking horse going on causeing you to over correct.

My buddy has a 08 and says his is rock stable at high speeds. He is like 230 so if you weight less then u might have to much preload for your likeing.

whtrthanu · « **Reply #2 on:** September 14, 2008, 11:11:34 AM »

I can tell you that i felt more stable in the corners with my 02 busa, for some reason the newer bike cant get into the corners the same way, i think its the weight, both bikes set up the same, i have already been in the grass with the new bike because I couldnt get it to come down fast enough...Also on the newer bike it feels smoother, but at high speeds, on a breezy day, the wind seems to get under the new bike causing it to feel unstable.....I had a few times were it felt like was going to go into a tank slapper, just not rock solid like the older bikes......i have to agree with you on it.......but when its calm outside, the new bike is pretty good, in a straight line

gjp1300 · « **Reply #3 on:** September 15, 2008, 05:24:53 AM »

That is exactly what I'm talking about at high speeds in a sweeper the bike doesn't perform like the Gen1 and seems to turn in slower,I think I'm going to lower the front an inch to try and keep the air from getting under the front of the bike cause to me it seems like an aerodynamics issue at high speeds and see how the bike reacts.They changed something on this 08 as far as the amount of pressure on your hands,on long rides on the Gen1 my hands would hurt,not on the 08 for some reason,so what did they change to accomplish that,and your right on calm days it's not nearly as bad that's why I think the air gets under the front at high speeds making the front move around,it has me baffled but I will get this bike to handle like my gen1,I can't have dudes on 600's staying with me on the highway cause I have to back out in the corner because the front end won't stay planted.Well I'll keep you posted I'm going to raise the back an 1" or lower the front an 1"to see if it keeps the front more planted,leaning more toward lowering the front to keep the air from getting under the fairing as much,it just feels like the bike doesn't have enough down force on the front tire.What do you guys think about that?

Quijinn · « **Reply #4 on:** September 15, 2008, 08:49:29 PM »

I would not lower the front a inch you will lose alot of ground clerance. Have you set your rear sag and softend up the front preload? I just cant belive the new front end would cause lift, seems something they would have been looking for when they wind tunnel tested the new bike. I know my 05 felt like crap to me till I redid the front forks, and set all my preloads and sags, then it was a whole new bike.

gjp1300 · « **Reply #5 on:** September 16, 2008, 07:56:31 PM »

These bikes comes set up for 160 to 170 lb riders,I really shouldn't have screw with rear sag and front preload that much,never did it on my GEN1's.The front springs are slightly stiffer big deal if anything it should make the bike better handling not worse at high speed,I probably have 80,000 miles on a GEN1 from canyons to 140 to 150 mph sweepers,so I know what I'm capable of on a busa,this 08 has me scratching my head,I'm raising the rear end an 1'' to see if it gives me more down force on the front tire,keep you posted.They didn't change rake or trail on this bike so what is different about it that could effect turn in and high speed cornering stability.My friend is making the links for me now and they will be installed after I go to the dragstrip on friday,it's a track rental so I will get alot of passes,hopefully run a 9.30 to 9.20 on pump gas,then switching to oxegenated fuel which gives you 8 to 10hp and hopefully go faster,the weather will be 65 sunny and dry,perfect conditions to go fast.

Quijinn · « **Reply #6 on:** September 16, 2008, 08:47:10 PM »

well sounds like you got it all figured out.

gjp1300 · « **Reply #7 on:** September 17, 2008, 03:10:43 AM »

I wouldn't say that but I will eventually figure it out,lol I'm going to give Lee Skierts a call to he's an ex roadracer for some input.

glenn71 · « **Reply #8 on:** October 03, 2008, 07:52:23 AM »

the 08 has a steeper head angle and less trail.This makes it steer easier at low speed but the reduced trail gives it less stability at high speed.raising the rear will make it worse.If you drop the rear, the rake and trail settings will more closely imitate a gen1,s settings.I also questioned the front wheels gyroscopic stability with the rotors sitting 5mm further apart to fit into radial calipers with the wide busa triple clamps.They should have just fitted gixxer triples with longer handle bars.

pr111 · « **Reply #9 on:** November 02, 2008, 03:21:44 PM »

Quote from: glenn71 on October 03, 2008, 07:52:23 AM

the 08 has a steeper head angle and less trail.This makes it steer easier at low speed but the reduced trail gives it less stability at high speed.raising the rear will make it worse.If you drop the rear, the rake and trail settings will more closely imitate a gen1,s settings.I also questioned the front wheels gyroscopic stability with the rotors sitting 5mm further apart to fit into radial calipers with the wide busa triple clamps.They should have just fitted gixxer triples with longer handle bars.

I remember reading some place that the chassis geometry was identical to the Gen 1 (rake, trail, ...).

Assuming it wasn't gale-force winds out there, I would think weave is caused by insufficient damping (rebound and compression). Try going stiffer at both ends, 2-clicks at a time. Also, are you absolutely sure about your throttle, that it was steady or smoothly increasing?

Busacharger · « **Reply #10 on:** May 20, 2009, 10:16:36 PM »

I just got my 08' and I'd have to agree with Glen71. what ever you do don't lower the front that far you'll eat up a lot of ground clearance. About a 1/4 " is all I'd do that should help the turn-in and mine was set up very firm for me (170lb) soften up that comp. a little at a time if you make drastic changes it's much harder to gage the tendencies of the suspension. Ground clearance is your friend, with it I could have made that 25MPH curve at 90MPH !!

Lowered I" front and rear.

gjp1300 · « **Reply #11 on:** June 09, 2009, 08:34:45 AM »

I havent been back to this post in a while,havent been on here much,my problem with my high speed handling has been solved.I have a friend that used to road race and has a pretty good understanding of how suspensions work so I described my problem to him and he told me put the front end back to stock,leave it alone so I said to him, why? He said the front end isnt your problem,I said really,so proceeds to explain to me that I obviously don't have enough down force on the front end so dial up the rebound in the rear 1 click at a time,which will keep the front end more planted,and if you notice the Gen2 does seem to squat more in the rear when you excellerate,maybe cause of more power or just the new suspension settings.Well
I did what he told me and by going up one click in the rear on the rebound made my front end stop weaving around,I was amazed but at the same time it made sense,maybe guys that are heavier dont have this issue,so anyone that has this problem with high speed stability give it a try and let me know if you get the same result.I feel at home on my busa again,Drive Safe.

COLDSTONE1300 · « **Reply #12 on:** June 10, 2009, 03:55:10 AM »

Glad you got it figured out! Thanks for passing info on to us

CADDYWOMPUS · « **Reply #13 on:** June 15, 2009, 09:20:10 PM »

Quote from: gjp1300 on June 09, 2009, 08:34:45 AM

,and if you notice the Gen2 does seem to squat more in the rear when you excellerate,

a sportbike suspension extends (rises) in the rear when you gas it . Unless you've lowered it and changed the geometry.

gjp1300 · « **Reply #14 on:** June 21, 2009, 09:32:41 PM »

A motorcycle squats when you accellerate,thats why if tour suspension is to stiff and you don't get any wieght transfer to the rear your bike will lite up the rear tire.The only way it would lift is if you had a shaft drive,like the Yamaha VMax,thats why they always have traction issues.I drag race and anybody else that does on this board I'm sure would agree with me,you need some wieght transfer to hook up.

CADDYWOMPUS · « **Reply #15 on:** June 21, 2009, 10:15:11 PM »

you're wrong gjp
I stand by my statement ,just dont feel like explaining it to you .

Quijinn · « **Reply #16 on:** June 21, 2009, 11:19:34 PM »

Sorry pete he is right, the sprockets try to pull together and cause the bike to compress the rear spring. If you sit still and throttle up the bike will extend however that is because the bike is not moving and trying to fold the swing arm in 2. This very subject was explained in the MC issue of the B king vs V max. Look at any drag bike leaving the line, they all squat.

gjp1300 · « **Reply #17 on:** June 22, 2009, 06:40:58 AM »

Quote from: zzr12pete on June 21, 2009, 10:15:11 PM

you're wrong gjp
I stand by my statement ,just dont feel like explaining it to you.

Please enlighten me pete,I'm always eger to learn,I defenitly dont know everything but I know one thing a rear suspension squats and then raises when you excellerate hard,thats why adjusting the rebound in the rear solved my problem,explained to me by a roadracer/dragracer who has a pretty good knowledge of how a suspension works.I'm interested to hear your explanation.

CADDYWOMPUS · « **Reply #18 on:** June 22, 2009, 06:43:48 AM »

Quote from: Quijinn on June 21, 2009, 11:19:34 PM

Sorry pete he is right, the sprockets try to pull together and cause the bike to compress the rear spring. If you sit still and throttle up the bike will extend however that is because the bike is not moving and trying to fold the swing arm in 2. This very subject was explained in the MC issue of the B king vs V max. Look at any drag bike leaving the line, they all squat.

They squat if they have been lowered . Stock sportbike swingarm geometry will push the tail up under acceleration.
Now go watch vid of a stocker leaving the line . Or watch a stocker on the dyno .Tail goes up.
It has to do with angle of swingarm . Forces transmited through swingarm are going uphill to push frame up and counter act the weightshift.You see it was designed this way for a good reason. Notice the swingarm pivot point is several inches higher than axel.
Now lower your bike and make the axel and S.A. pivot point the same hight you now have a wallowing pig that DOES squat when you gas it.
Roadracers know very well that being on the gas in a curve gives more ground clearance.
Being on back brake or downshifting will produce the opposite reaction and pulls the tail down. Some call it settling the rear

No degree in physics here but I do understand it .I just suck at explaining it.

gjp1300 · « **Reply #19 on:** June 22, 2009, 08:14:24 AM »

Your front end is in a chock on the dyno so I cant see that as a good comparson to real world driving down the road as to the way your overall suspension would behave,but maybe you are correct I wll have to do some research on the subject,I cant see a bike getting much traction with the rear lifting under acceleration,even a stocker leaving the line.I'm not a physics major either so who knows but I do know one thing my bike is stock hieght,the wallowing is gone and my front end is stable at high speeds,accomplished by stiffening up the rear dampening one click keeping the front end more planted,so I'm happy.

Quijinn · « **Reply #20 on:** June 22, 2009, 06:39:31 PM »

Yah after doing some reading and some thinking I know Pete is right. If the swing arm pivot is higher then the front and rear sprocket, and if and only if the weight transfere does not overcome the rear spring then the bike would lift. IF the rear spring compress's to much, as with most stock bikes with big guys then the rear end will sag from weight transfere and reduce the sprocket to pivot angle at which point the chain will further pull the bike down as its past the 0 point and no going negative.

The reason it would lift is the front sprocket it trying to pull the rear sprocket up to meet it. Since the sprocket is fixed to the swing arm and can not just pull straight forward, it will then try to pull the sprocket under the pivot point. If all 3 points are in a straight line then the chain would have to bend the swing arm in order to pull the sprocket forward. If the pivot point is lower then the 2 sprockets the front sprocket would pull the rear one over the pivot making the bike drop more.

Doing a burn out or even on a dyno cause's this lift. The reason is since there is no weight transfere, without the transfere to compress the rear spring then the front sprocket would simple pull the rear sprocket forward and the only way it can do that is to pull the swing arm down and make it shorter between the 2 points.

If the spring is to soft it will drop the rear end enough to allow the pivot point to drop lower then the sprockets and then the front would pull the rear forward over the pivot and pulling the swing arm up.

Another way to prove it, very simple. Look at any bike acceling in 2nd or 3rd gear where there front tire is planted and the rear chain will be sloppy on the bottom. The rearson is the swing arm is shorter and the chain on the top is shorter between the 2 sprockets and the slack is now on the bottom. If the bike really squated then the chain on the bottom would be tigher If you look at a drag bike in first gear it will squat and the chain gets really tight on the bottom, the longer it stays compressed the tighter the chain is.

If you put a 350lb guy on a stock spring and have him launch it then it would squat get traction and wheelie. A light weight person would cause the bike to lift cause there is not enough weight to overcome the spring and it would just spin.

Pete sorry bro you are right, I was just not looking at all the facts when I made my statement, it was just a assumption based on what I have seen over the years, but I did leave out some facts. I have seen many chains get sloopy on the bottom and its simply because ther rear end is lifting.

GSXRTURBO1 · « **Reply #21 on:** June 23, 2009, 01:32:53 PM »

Quote from: Quijinn on June 22, 2009, 06:39:31 PM

If you look at a drag bike in first gear it will squat and the chain gets really tight on the bottom, the longer it stays compressed the tighter the chain is.

I'm no expert on this, but I've seen a LOT of pictures of drag bikes leaving the line in 1st gear, and every one of them I can remember has the chain very tight on top and very, very loose on the bottom.

GSXRTURBO1 · « **Reply #22 on:** June 23, 2009, 02:37:07 PM »

gjp1300 · « **Reply #23 on:** June 23, 2009, 09:08:50 PM »

What pete is saying is once you lower your bike you change the angle of the swingarm,instead of the swingarm angle pitching down its more level,which lowers pivot point of the swingarm losing the scissor effect which would normaly be raising the rear end as you leave the line or accelerate hard,when your at stock hieght.Does that sound right Pete,lol.I just wonder how much the rear shock is compressing in the process when your at stock hieght accelerating hard,the rear shock does have more travel I would think than the amount the swingarm moves,or maybe it simultaneous and the bike stays at the same hieght,when I accelerate on my bike it doesn't seem like the rear end is lifting my ass up,definitly less tranfer now since I made that rebound adjustment in the rear.

Quijinn · « **Reply #24 on:** June 24, 2009, 01:18:34 AM »

Quote from: GSXRTURBO1 on June 23, 2009, 01:32:53 PM

Quote from: Quijinn on June 22, 2009, 06:39:31 PM
If you look at a drag bike in first gear it will squat and the chain gets really tight on the bottom, the longer it stays compressed the tighter the chain is.

I'm no expert on this, but I've seen a LOT of pictures of drag bikes leaving the line in 1st gear, and every one of them I can remember has the chain very tight on top and very, very loose on the bottom.

Yah I guess the wb is getting shorter either way, and that is why the chain gets lose on the bottom. Only place it can be tight in where the front sprocket, pivot point and rear sprocket are in line.

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Author Topic: 08 handling issues (Read 26137 times) Tweet