ADVrider

Go Back   ADVrider > Bikes > Thumpers
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-05-2009, 05:21 PM   #31
mcftw
hxc n33b
 
mcftw's Avatar
 
Joined: Apr 2008
Location: Lost in Cali
Oddometer: 454
Quote:
Originally Posted by MTDewX8
I remember my test ride and was very surprised on its dive when braking.

Sounds like you're more of talking about the air shock causing you to rise when you hit the front brake?
__________________
"Open up your mind and think like me." Jason Mraz
mcftw is offline   Reply With Quote
Old 01-05-2009, 08:44 PM   #32
TDM Rider
Gnarly Adventurer
 
TDM Rider's Avatar
 
Joined: Apr 2006
Location: Franklin, TN
Oddometer: 154
Agree with the brake dive issue

I too feel the forks dive a bit too much under braking on the road, not only compared to my GS (which is obvious) but also compared to my KLX and an old XR that I have. I have played somewhat with the compression settings but I still feel the bike could use higher rate, perhaps progressive springs.

I weigh-in at 190 without riding gear so I may just be beyond what the stock set-up is rated for.

Cheers,
TDM Rider is offline   Reply With Quote
Old 01-05-2009, 09:35 PM   #33
ropedrag
Gnarly Adventurer
 
ropedrag's Avatar
 
Joined: Sep 2008
Location: Seattle
Oddometer: 312
I'm with mcftw, the air shock could very likely be causing what your blaming the forks on. If you have ABS try this out if your comfortable doing so. I would come up to a stop sign and grab a HANDFUL of front brake to the point of the ABS kicking in and was amazed at the dive/buck the bike produced. Then I stared playing with a touch of rear brake while performing the same maneuver and was again amazed on how little rear brake it takes to eliminate most of the dive/buck. I'm not to the point of replacing the air shock but it does seem to perform a bit different than a conventional shock for sure and I feel some of that "difference" shows up in how the forks react.
__________________
Do not mistake for wisdom the fantasies of your sick mind

ropedrag is offline   Reply With Quote
Old 01-05-2009, 11:58 PM   #34
Max Kool
Xtankteam™
 
Max Kool's Avatar
 
Joined: Jan 2004
Location: Los Angeles
Oddometer: 3,227
Quote:
Originally Posted by mcftw
Sounds like you're more of talking about the air shock causing you to rise when you hit the front brake?
Exactly! As soon as you apply a firm bront brake, the air shock will expand nearly completely. Which is felt as front end dive.
Max Kool is offline   Reply With Quote
Old 01-07-2009, 08:15 PM   #35
Skaife
--------------
 
Skaife's Avatar
 
Joined: Feb 2008
Location: Arizona
Oddometer: 191
So out of curiousity, what is everyone running for current fork settings and what's your riding style?
Skaife is offline   Reply With Quote
Old 01-07-2009, 08:27 PM   #36
mcftw
hxc n33b
 
mcftw's Avatar
 
Joined: Apr 2008
Location: Lost in Cali
Oddometer: 454
I ride it stock and when someone tells me I'm riding slow I blame it on the stock settings .
__________________
"Open up your mind and think like me." Jason Mraz
mcftw is offline   Reply With Quote
Old 01-08-2009, 08:46 AM   #37
johan
Gnarly Adventurer
 
johan's Avatar
 
Joined: Jul 2005
Location: Mjölby, Sweden
Oddometer: 249
Quote:
Originally Posted by Max Kool
Exactly! As soon as you apply a firm bront brake, the air shock will expand nearly completely. Which is felt as front end dive.
Can we have this confirmed by someone who experienced excessive diving, change the shock only, and found the diving behavior to disappear
__________________
08´KTM 250 EXC-R (Yes, it's getting silly...)
08´KTM 450 EXC-R (can't stop buying...)
07' BMW X-Challenge (For the longish trips)
03' KTM 640Adv (Passed on to other hooligan)
04' BMW 650 Dakar (Oops, totalled)
81' YAMAHA YZ 125 (Died in my arms of old age)
johan is offline   Reply With Quote
Old 01-08-2009, 12:10 PM   #38
Max Kool
Xtankteam™
 
Max Kool's Avatar
 
Joined: Jan 2004
Location: Los Angeles
Oddometer: 3,227
I replaced the rear shock with a conventional one (Hyperpro) and the bike feels way better balanced. Not only under braking, but under most all circumstances. Like for instance while accellerating (where with the airshock the rear would squat quite a bit).

Fact is, as soon as you unload the airshock a bit, it will extend nearly all the way. The way the front and the rear react to changes in load make the stock bike feel unbalanced between front and rear. Too much rear squat if you shift your weight a few inches to the rear, put one foot down and the shock completely extends, too little rebound damping.

With the airshock you have to adapt your riding style to the characteristics of the suspension. You can live with it, it's not bad, but the bike will always feel "strange" or "different". With a "normal" shock (that of course needs to be dialed in by an expert) you just ride and forget to adapt.

At least, that is my experience.
Max Kool is offline   Reply With Quote
Old 01-08-2009, 12:38 PM   #39
Luke
GPoET&P
 
Luke's Avatar
 
Joined: Aug 2004
Location: Idiotville, OR
Oddometer: 4,037
Quote:
Originally Posted by Max Kool
I replaced the rear shock with a conventional one (Hyperpro) and the bike feels way better balanced. Not only under braking, but under most all circumstances. Like for instance while accellerating (where with the airshock the rear would squat quite a bit).

Fact is, as soon as you unload the airshock a bit, it will extend nearly all the way. The way the front and the rear react to changes in load make the stock bike feel unbalanced between front and rear. Too much rear squat if you shift your weight a few inches to the rear, put one foot down and the shock completely extends, too little rebound damping.

With the airshock you have to adapt your riding style to the characteristics of the suspension. You can live with it, it's not bad, but the bike will always feel "strange" or "different". With a "normal" shock (that of course needs to be dialed in by an expert) you just ride and forget to adapt.

At least, that is my experience.

Sounds like a traditional shock that has too light a spring and too much preload. When setting up the air shock, does it match the dirtbike rule of 10% sag unladen/30% sag laden?
Luke is offline   Reply With Quote
Old 01-08-2009, 01:16 PM   #40
FlyingFinn
Beastly Adventurer
 
Joined: Jul 2005
Location: San Jose, CA
Oddometer: 1,029
Hi Luke. Big fat NO IT DOES NOT on that.

No matter how little (down to any practical value) air pressure you run in the shock it has ZERO sag unladen. And that makes it so annoying.

You unload your wight off the bike, even put one foot down, and the ass of the bike springs up sky high...

--
Mikko
FlyingFinn is offline   Reply With Quote
Old 01-08-2009, 02:30 PM   #41
mcftw
hxc n33b
 
mcftw's Avatar
 
Joined: Apr 2008
Location: Lost in Cali
Oddometer: 454
If it weren't for the way it popped back up I would actually like it. I like how easy it is to adjust when switching between on and offroad.
__________________
"Open up your mind and think like me." Jason Mraz
mcftw is offline   Reply With Quote
Old 01-08-2009, 03:01 PM   #42
Dagwood_55
Beastly Adventurer
 
Dagwood_55's Avatar
 
Joined: Jun 2007
Location: The Ozarks
Oddometer: 1,301
Anyone that has replaced the rear shock ride 2 up sometimes?? And how does the bike/shock compensate for 1up vs 2up??

Or if I call Teds Beemer (or whoever), do I buy a shock for my 185 lb wt or the 295b wt of me and passenger?? Will the shocks adjust that much??
__________________
Live long, love much, laugh often, and
Ride, Ride, Ride.....
Dagwood_55 is offline   Reply With Quote
Old 03-01-2009, 02:01 AM   #43
raw_saddle
Adventurer
 
raw_saddle's Avatar
 
Joined: Jan 2009
Location: Oz
Oddometer: 20
Sorry, this is back to the front end.
I found it not bad when going over big hits but when I had a run over a really long run of corrugation surfaces, the front end hammered and speed had to be reduced accordingly.
After running through all the posts regarding this, there didn't seem to be a non-expensive solution.
Some posts indicated that a lighter fork oil might aid things.
Anyway, finally got around to pulling the front end off thinking lighter oil may be a reasonable alternative.
After pulling the compression side off and removing the spring, started moving the damper rod up & down. There is an inner rod that links to the clickers, and with the stock oil, it was apparent that this only really controls the bottoming out, so any adjustments within the +top 5 clicks are effective.
Completely drained this and added 5W Motul fork oil (cause it was the only stuff as well as 10w that I had at the time). Noted that these were only 1litre bottles and after 500ml, the level did not come up to the 80mm std height, so added about 150ml of 10w Motul (extra bottle that was spare).
Set the oil level at 95mm from top of sliders without springs just to see whether this might soften the minor hits.
Did the same to the rebound side, but found draining the oil required more diligence. Seems that the rebound side actually controls compression and rebound as changing pressure on the adjustment rod provided uniform alterations (compression/rebound).
So filled this fork in the same manner (500ml 5w and ~150ml 10w) and 95mm from the top of compressed sliders, ensuring all air bubbles were purged.
Another thing to note. The std spring are straight wound (ie. not progressive). They also have a 40mm length plastic preload spacer, and the static sag is about 30mm.
Anyway, with the forks back together and taking it out for a test run trying to find as much variation in road surface, I can say that on std settings (11 clicks out on both), the result is much smoother and while minor bumps are noticeable, that are not harsh as before.
With some adjustments of the clickers, this may be improved, but the main finding is that the compression side only controls bottoming out and the rebound side controls most of the stroke.
BTW. The standard fork oil seems to be about 20-30w. Seems quite thick, but might explain the harshness over small corrugations.
Just a thought.
raw_saddle is offline   Reply With Quote
Old 03-01-2009, 05:53 AM   #44
RV8Pilot
Blue,Green,Blue,Gree.....
 
RV8Pilot's Avatar
 
Joined: Jun 2004
Oddometer: 215
Quote:
Originally Posted by raw_saddle
Sorry, this is back to the front end.
I found it not bad when going over big hits but when I had a run over a really long run of corrugation surfaces, the front end hammered and speed had to be reduced accordingly.
After running through all the posts regarding this, there didn't seem to be a non-expensive solution.
Some posts indicated that a lighter fork oil might aid things.
Anyway, finally got around to pulling the front end off thinking lighter oil may be a reasonable alternative.
After pulling the compression side off and removing the spring, started moving the damper rod up & down. There is an inner rod that links to the clickers, and with the stock oil, it was apparent that this only really controls the bottoming out, so any adjustments within the +top 5 clicks are effective.
Completely drained this and added 5W Motul fork oil (cause it was the only stuff as well as 10w that I had at the time). Noted that these were only 1litre bottles and after 500ml, the level did not come up to the 80mm std height, so added about 150ml of 10w Motul (extra bottle that was spare).
Set the oil level at 95mm from top of sliders without springs just to see whether this might soften the minor hits.
Did the same to the rebound side, but found draining the oil required more diligence. Seems that the rebound side actually controls compression and rebound as changing pressure on the adjustment rod provided uniform alterations (compression/rebound).
So filled this fork in the same manner (500ml 5w and ~150ml 10w) and 95mm from the top of compressed sliders, ensuring all air bubbles were purged.
Another thing to note. The std spring are straight wound (ie. not progressive). They also have a 40mm length plastic preload spacer, and the static sag is about 30mm.
Anyway, with the forks back together and taking it out for a test run trying to find as much variation in road surface, I can say that on std settings (11 clicks out on both), the result is much smoother and while minor bumps are noticeable, that are not harsh as before.
With some adjustments of the clickers, this may be improved, but the main finding is that the compression side only controls bottoming out and the rebound side controls most of the stroke.
BTW. The standard fork oil seems to be about 20-30w. Seems quite thick, but might explain the harshness over small corrugations.
Just a thought.
When I put my progressive springs in I changed to 5w and found that the front end felt a little better over the small stuff and still retained enough stiffness to not bottom out on large hits. Not sure if the improvement was the springs or the lighter fork oil though since i did both at the same time. Not much help, huh?
__________________
1200 GSA-DR650-1961 BSA Gold Star-Moto Guzzi 1100i Sport-Victory Vision Tour-CL77
Vans RV8
RV8Pilot is offline   Reply With Quote
Old 03-01-2009, 03:40 PM   #45
FlyingFinn
Beastly Adventurer
 
Joined: Jul 2005
Location: San Jose, CA
Oddometer: 1,029
Thanks for sharing Raw!
This kind of new, useful, information is highly appreciated and will help us collectively accumulate good knowledge base about these bikes.
I'll give the 5W oil a try when taking the forks off the bike, but probably will leave the oil level as-is. Especially since the springs are straight-rate, as you said.

--
Mikko

Quote:
Originally Posted by raw_saddle
....Seems that the rebound side actually controls compression and rebound as changing pressure on the adjustment rod provided uniform alterations (compression/rebound).

...the main finding is that the compression side only controls bottoming out and the rebound side controls most of the stroke.
FlyingFinn is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 03:17 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014