Technical Discussion Topics related to Technical Issues

Front Forks - Need advice.

Old 09-21-2006, 02:26 PM
  #1  
Member
Squid
Thread Starter
 
Join Date: Aug 2006
Location: Horley (Near Gatwick Airport) UK
Posts: 63
Tempest is on a distinguished road
Front Forks - Need advice.

I'm not really very happy with the way the front forks on my VTR1000 are performing.
To the point of not actually enjoying cornering at all.

(not good for a bike eh?)

I think 2 people owned it prior to the owner I bought it from, and I guess I have a sneeky feeling (total guess) that perhaps someone in the past has perhaps tweaked the springs. The previous owner had not done anything to the forks, (even change the oil) and I've not either.

Let me run over a few things (hope you can be bothered reading!)

When reading about the Firestorm, you keep hearing about soft front ends, and how you really need to turn up the settings to make it harder at the front end.
I mentioned this to previous owner (when buying the bike from him) and he told me, he never found this, and found it best on SOFT setting.

I actually turned it up (to recommended settings on this forum) and it was like a block of concrete, so I backed them back down to soft/default settings again.

Let me TRY to describe what it feels like (as I'm no fork expert) and am quite a biking novice still really.

When you go round a corner, with even tiny lumps and bumps in the tarmac, it really feels to me like the front end is going to break away.
It may be my imagination, but it feels like the front wheel is bouncing off the road imperfections, rather than the forks soaking up the road.

I feel MUCH more secure cornering with my TDM850 Yamaha than on the Firestorm.

Yet, there is a LOT of movement when breaking.
The fork dive I guess you could say.

It's just (as I say) round round corners, it feels like the front tyre is bouncing up and down as you are leaning over and feels VERY disconcerting. To the point I'm actually worried about leaning it.

The front tyre still have molding stalks on it (not been over far enough to wear them off)

But (as I say) when you break in a straight line, the front end does dip down quite a bit.

Does this sound normal, or very odd?

This is on quite a soft setting as when I made it harder, if felt even worse

So as far as I know we have the springs (which may or may not have been changed by a previous owner)
The oil which may or may not have been changed.
and the two adjusters on each fork leg.

I need to nail something down here, but bit unsure quite where to start.

would appreciate some advice.

I could for example unscrew the top of the forks and take a look at the springs, but I have no idea what I'd be looking for anyway.

Thanks for reading

Oh yes, tyres on the bike are currenty Metzler ME Z4 which I'm not sure are really a cornering tyre as such (if that makes any difference?)
Tempest is offline  
Old 09-21-2006, 05:46 PM
  #2  
Senior Member
SuperBike
 
L8RGYZ's Avatar
 
Join Date: Nov 2004
Location: Richmond, Virginia
Posts: 1,315
L8RGYZ is an unknown quantity at this point
I have stock forks & rarely have any problems cornering them. I set the front preload right at 2 rings showing & set the rebound 1 turn counter clock-wise from full stiff. I run the rear preload at the stock setting (on the second step) and the rebound 1 turn out from full stiff.
Seems to work fine for all day rides on the backroads & in the mountains. I did stiffen things up a little on the front for a track day and it seemed to work great... then again, i'm not that fast.
L8RGYZ is offline  
Old 09-21-2006, 07:34 PM
  #3  
Senior Member
SuperBike
 
JamieDaugherty's Avatar
 
Join Date: Aug 2005
Location: Fort Wayne, IN
Posts: 1,836
JamieDaugherty is an unknown quantity at this point
It sounds to me like your springs are too soft. The bouncing around part is what clued me in. Mine bounce and have a tendency to allow the front to wander through hard turns. Maybe the damping and/or oil weight is all wrong too, you might be blaming the springs for something they have no fault in. Try this: turn the adjustment screws all the way out. Ride a familiar stretch of road. Then turn them all the way in and ride the same stretch again. Note the differences. Whichever way felt better start there. Turn the screws 1/2 turn away from the full (either hard or soft) setting until either the handling gets worse or you can't tell the difference. Go back to the previous setting and try it for a while. Do the same for the rear, I think you'll find it makes a huge difference. I gained 15mph of corner speed in my favorite corner after following this procedure.
JamieDaugherty is offline  
Old 09-22-2006, 05:20 AM
  #4  
Member
Squid
Thread Starter
 
Join Date: Aug 2006
Location: Horley (Near Gatwick Airport) UK
Posts: 63
Tempest is on a distinguished road
Thanks.

I am tempted to take the fork tops off and pull the springs out to check their dimensions etc (take some photo's)

Then perhaps someone will be able to confirm at least the springs are original.

I kinda need to know what I'm dealing with.

All I know right now is, going round corners, the front wheel feels like it's bouncing up and down, and could at any time slip away from me.
Hence I'm scared to corner too hard just in case.
Tempest is offline  
Old 09-22-2006, 06:50 AM
  #5  
Sprung
World Champion
 
Hawkrider's Avatar
 
Join Date: Dec 2004
Location: Fulton, MO
Posts: 105,285
Hawkrider will become famous soon enoughHawkrider will become famous soon enough
Well, a little bit more information would be helpful in this case. What's your weight (in US pounds, please)? What are your current settings - turns from full in on rebound and lines showing on preload? Are you having any problems with the rear? Even knowing this information will make it a little more difficult to troubleshoot without knowing what you've got in the forks, but we can try.

Preload will not make the bike "stiffer". It will change the ride height, hence the term "sag". It changes where in the stroke of the forks or shock that the suspension operates.

Compression damping is not adjustable on this bike. That can only be changed with oil weight and/or revalving the forks.

My gut feeling tells me you are too heavy for the bike and you need to change springs to get proper sag, and have the forks revalved to your liking and to match the springs.
Hawkrider is offline  
Old 09-22-2006, 07:03 AM
  #6  
Senior Member
Back Marker
 
Join Date: Jun 2004
Location: East Tennessee
Posts: 208
99Hawk
Yes, you need to pull a spring to see if you're dealing with a stock spring first. The stock springs have more coils at one end, aftermarket springs like RaceTech will have uniform coils (bottom example here):



Where is your rebound set?

After you pull one spring to take a look also check the oil level while you're at it. You'll loose some oil on the spring as you pull it but some reference is helpful. The oil level specs are for an extended tube without the spring, with the tube verticle BUT you can take the measurement while the fork is still mounted 'at the back of the tube' and add 10mm. This will be very close to the oil level when verticle so it makes things easier to get a starting number and later adjust.

How does your front tire look? Many miles? Scalloped at all??

How many miles on the bike? Bushings may be an issue.

Having the correct springs and correct rebound setting will normally make the front work well enough assuming there isn't a tire or bushing problem. You may want to consider compression mods like Gold valves afterwards.

===== EDIT =====
Greg - we're hitting the keyboard at the same time
99Hawk is offline  
Old 09-22-2006, 07:36 AM
  #7  
Senior Member
SuperSport
 
Join Date: Mar 2005
Location: Laurel, MD
Posts: 758
jschmidt
And keep in mind that soft springing combined with stiff rebound damping can lead to plenty of hard landings when going over bumps.
jschmidt is offline  
Old 09-22-2006, 07:54 AM
  #8  
Sprung
World Champion
 
Hawkrider's Avatar
 
Join Date: Dec 2004
Location: Fulton, MO
Posts: 105,285
Hawkrider will become famous soon enoughHawkrider will become famous soon enough
Originally Posted by 99Hawk
The oil level specs are for an extended tube without the spring...
Actually the spec is with spring out fork fully compressed. That's the "spec" but if you want to adjust the level to YOU then the oil level should be high enough that it covers the bottom of the cartridge and low enough that you *almost* bottom the forks during very hard braking with bumps. If you bottom out add 10ml of oil to each fork at a time and try again.
Hawkrider is offline  
Old 09-22-2006, 08:52 AM
  #9  
Senior Member
Back Marker
 
Join Date: Jun 2004
Location: East Tennessee
Posts: 208
99Hawk
Originally Posted by Hawkrider
Actually the spec is with spring out fork fully compressed. That's the "spec" but if you want to adjust the level to YOU then the oil level should be high enough that it covers the bottom of the cartridge and low enough that you *almost* bottom the forks during very hard braking with bumps. If you bottom out add 10ml of oil to each fork at a time and try again.
Wooops - what was I thinking - -
99Hawk is offline  
Old 09-22-2006, 11:30 AM
  #10  
Member
Squid
Thread Starter
 
Join Date: Aug 2006
Location: Horley (Near Gatwick Airport) UK
Posts: 63
Tempest is on a distinguished road
Originally Posted by JamieDaugherty
It sounds to me like your springs are too soft. The bouncing around part is what clued me in. Mine bounce and have a tendency to allow the front to wander through hard turns. Maybe the damping and/or oil weight is all wrong too, you might be blaming the springs for something they have no fault in. Try this: turn the adjustment screws all the way out. Ride a familiar stretch of road. Then turn them all the way in and ride the same stretch again. Note the differences. Whichever way felt better start there. Turn the screws 1/2 turn away from the full (either hard or soft) setting until either the handling gets worse or you can't tell the difference. Go back to the previous setting and try it for a while. Do the same for the rear, I think you'll find it makes a huge difference. I gained 15mph of corner speed in my favorite corner after following this procedure.
Thanks for the advice.

Which screws are you talking about here?

The large outer nut on top of the fork legs (with the groves around the outside) or the small inner screw?
Tempest is offline  
Old 09-22-2006, 11:33 AM
  #11  
Member
Squid
Thread Starter
 
Join Date: Aug 2006
Location: Horley (Near Gatwick Airport) UK
Posts: 63
Tempest is on a distinguished road
My Sizes are:

Height 6ft 5" Tall = Very tall!

Weight = 12 Stone (168lbs) or in metric 76.36kg.

To basically tall and slim (or skinny if you want to be rude)
Tempest is offline  
Old 09-22-2006, 02:37 PM
  #12  
Member
Squid
Thread Starter
 
Join Date: Aug 2006
Location: Horley (Near Gatwick Airport) UK
Posts: 63
Tempest is on a distinguished road
Following on from the 2 other questions above.

2 other VERY BASIC questions.

The two adjusters on the forks

The Preload Adjuster (large thing with the grooves on the outside)
And the small inner Rebound Damper screw.

In basic terms, what exactly are these 2 items actually adjusting? and what effect does changing these individual things do?

My guess (prob wrong) is that the Preload actually presses on the spring to make the ride harder and your loading the spring.
And the rebound is some kind of oil pathway thing that slows down the oil passing thru and changes how fast the spring can extend the forks back to full height again.

Am I right, or wrong?
Tempest is offline  
Old 09-26-2006, 02:33 PM
  #13  
Member
Squid
Thread Starter
 
Join Date: Aug 2006
Location: Horley (Near Gatwick Airport) UK
Posts: 63
Tempest is on a distinguished road
Just a little update here:

Put cable ties around my forks and went out for a run (did some heavy braking)

the cable ties moved up and when back home measured, and they showed the forks had moved 77mm (tiny fraction over 3") in total during my ride.

Perhaps I could have done some even higher speed braking, but 77mm does not sound much, as the manual is quoting the fork travel as 109mm.

A web site here:
http://www.gostar-racing.com/informa...ion_set-up.htm
About 1/3rd the way down the page, show some forks with cable ties on (as I copied) and says that after a heavy run they should be within 10mm of your total travel.

Well, as mine only travelled 77mm and according to the manual, total travel is 109mm, I've got a LOT to go yet.

About 20mm more travel (97mm) would be around the right figure.

And I have my preload adjuster on the 5th Groove!!!!!

Will have to do some heavier braking tomorow.

any thoughts on all of this?
Tempest is offline  
Old 09-26-2006, 07:46 PM
  #14  
evil man of nothing
MotoGP
 
captainchaos's Avatar
 
Join Date: Jan 2006
Location: Boynton Beach, FL
Posts: 4,200
captainchaos is on a distinguished road
I know this is going to sound stupid and too obvious but I can't remember how many times I've gotten on my friends bikes-ZX11's, Ducati 916's, etc and was scared to death the first turn I went around because they started weaving and were impossible to turn without feeling like I was going to crash. After asking them what the hell was up I asked when the last time was they checked the AIR in the tire and I remember both bikes being somewhere south of 10 lbs! I know it's kinda simple and obvious but haven't heard anyone at least mention it yet...
captainchaos is offline  
Old 09-26-2006, 10:15 PM
  #15  
Slacker
Superstock
 
BeerHunter's Avatar
 
Join Date: Jun 2005
Location: San Antonio, TX
Posts: 489
BeerHunter is an unknown quantity at this point
Tempest, make sure you are measuring fork travel from the cable ties to the top of the fork seal/dust boot with the forks FULLY extended(front wheel off the ground). You need total travel, not just movement from settled position to max compression.
BeerHunter is offline  
Old 09-26-2006, 11:26 PM
  #16  
Member
Squid
Thread Starter
 
Join Date: Aug 2006
Location: Horley (Near Gatwick Airport) UK
Posts: 63
Tempest is on a distinguished road
Originally Posted by captainchaos
I know this is going to sound stupid and too obvious but I can't remember how many times I've gotten on my friends bikes-ZX11's, Ducati 916's, etc and was scared to death the first turn I went around because they started weaving and were impossible to turn without feeling like I was going to crash. After asking them what the hell was up I asked when the last time was they checked the AIR in the tire and I remember both bikes being somewhere south of 10 lbs! I know it's kinda simple and obvious but haven't heard anyone at least mention it yet...
Thanks for that.
Actually I did just check the air last week in case it was out. (put a few more lbs in) but no difference.

I'm aware some of this may be tyres, but I'd like to get forks right(ish) THEN move onto tyres.
Tempest is offline  
Old 09-26-2006, 11:28 PM
  #17  
Member
Squid
Thread Starter
 
Join Date: Aug 2006
Location: Horley (Near Gatwick Airport) UK
Posts: 63
Tempest is on a distinguished road
Originally Posted by BeerHunter
Tempest, make sure you are measuring fork travel from the cable ties to the top of the fork seal/dust boot with the forks FULLY extended(front wheel off the ground). You need total travel, not just movement from settled position to max compression.
Funny you should say this, and you are 100% correct, and it's something I did not think about at first.

For some reason it never entered my head that the forks would be down at all with the bike on it's side stand. But yes, I guess they may already be a bit compressed just taking the weight of the front of the bike.

I need to jack up, under the engine to get the front wheel off the ground (as you say) to check the measurment again.

Thanks for pointing this out
Tempest is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
VTRsupersport
Modifications - Performance
2
02-29-2012 05:09 AM
lynchie
General Discussion
11
04-12-2011 01:10 PM
D VTR RIDER
Modifications - Performance
7
01-03-2011 07:34 PM
cagedruss
Classifieds
0
06-20-2008 06:19 PM
OldHawkNewB
Classifieds
4
03-19-2007 04:17 PM


Thread Tools
Search this Thread
Quick Reply: Front Forks - Need advice.


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.

All times are GMT -7. The time now is 10:08 PM.


© 2019 MH Sub I, LLC dba Internet Brands