front fork springs ? & recomendations
11-13-2007 | 12:21 AM
#1
Thread Starter
Senior Member
Superstock
Joined: Jul 2007
Posts: 433
From: Los Angeles & Winston Salem
front fork springs ? & recomendations
Hi All
Ok I have slowly been setting up by hawk....just been so busy it's taken a while...
I have my front brake upgrade ready to go...ss/lines and ebc hh pads.
And now want to upgrade the front forks....After spending a couple of hours reading all the posts on fork springs,oil weight and oil height I'm just more confused?
I have done the springs and oil thing before on an sv650 and it took me three attempts to get it right? I would like to do it just the once this time.
So here go's I weight 160lbs mostly ride street but managed to do at least four track days a year.
So far I'm thinking 85's for the springs from racetech...5wt oil silkolene and 125mm air gap?
I just would like a nice allround balance if possilbe.
Hawkrider if you are reading this? I regard your advice highly anyone else who weighs around the same as me? ....not interested in doing any gold valves...just springs and oil for now..thanks all....ps I just installed some pilot powers....if I install the springs will I have to lower the forks any?...if so where doing I measure from on the fork leg?....ie: is it from the underside of the fork cap?...thanks all for any replies
Ok I have slowly been setting up by hawk....just been so busy it's taken a while...
I have my front brake upgrade ready to go...ss/lines and ebc hh pads.
And now want to upgrade the front forks....After spending a couple of hours reading all the posts on fork springs,oil weight and oil height I'm just more confused?
I have done the springs and oil thing before on an sv650 and it took me three attempts to get it right? I would like to do it just the once this time.
So here go's I weight 160lbs mostly ride street but managed to do at least four track days a year.
So far I'm thinking 85's for the springs from racetech...5wt oil silkolene and 125mm air gap?
I just would like a nice allround balance if possilbe.
Hawkrider if you are reading this? I regard your advice highly anyone else who weighs around the same as me? ....not interested in doing any gold valves...just springs and oil for now..thanks all....ps I just installed some pilot powers....if I install the springs will I have to lower the forks any?...if so where doing I measure from on the fork leg?....ie: is it from the underside of the fork cap?...thanks all for any replies
11-13-2007 | 04:41 AM
#2
Out of my mind, back in 5
MotoGP
Joined: Nov 2006
Posts: 6,109
From: Skurup, Sweden
The basic numbers you gave sounds about rigth with your weight... If you only go for springs, not valves, the difference in airgap should only compensate for the difference in mass of the new spring...
Tho I'd recommend considering the main Goldvalve... Doing it all in one go saves you the trouble of disassembling it all twice... and with new springs, the need for a new valve goes from "might need" to "need valve now!"...
Skip the rebound valve as the stock one is good enough there... but the main valve is a BIG bottleneck on the VTR's stock forks... The holes in the stock valve is about a 1/3'rd of the GW...
Changing the springs shouldn't have anything to do with changing the position of the fork legs... the reason for that is to increase steering response (less ground clearence, if you are tall like me, raise the back instead...)
On the fork leg there is a little notch for a locking ring in standard position... use this as a reference point when measuring is my advice...
Tho I'd recommend considering the main Goldvalve... Doing it all in one go saves you the trouble of disassembling it all twice... and with new springs, the need for a new valve goes from "might need" to "need valve now!"...
Skip the rebound valve as the stock one is good enough there... but the main valve is a BIG bottleneck on the VTR's stock forks... The holes in the stock valve is about a 1/3'rd of the GW...
Changing the springs shouldn't have anything to do with changing the position of the fork legs... the reason for that is to increase steering response (less ground clearence, if you are tall like me, raise the back instead...)
On the fork leg there is a little notch for a locking ring in standard position... use this as a reference point when measuring is my advice...
12-02-2007 | 02:49 AM
#3
Thread Starter
Senior Member
Superstock
Joined: Jul 2007
Posts: 433
From: Los Angeles & Winston Salem
done
ok I finally got round to messing with my forks......just installed .85 racetech springs.....7wt bel-ray fork oil all the bike store next to me had.....set fork oil air gap @ 145mm...(springs out)..
Not ridden it yet but just from pushing up & down in the garage it feels a lot different..
The thing I can see now with the stock springs is all the sag is used up by the soft part of the stock progressive spring.
Well I ride it a little tomorrow see how it all feels....
Also I lowered the forks 7mm..in the triples...
Not ridden it yet but just from pushing up & down in the garage it feels a lot different..
The thing I can see now with the stock springs is all the sag is used up by the soft part of the stock progressive spring.
Well I ride it a little tomorrow see how it all feels....
Also I lowered the forks 7mm..in the triples...
12-02-2007 | 04:05 PM
#5
Junior Member
Squid
Joined: Dec 2007
Posts: 2
New guy, here. I had Dan Kyle set up my front forks and rear shock. Pure magic. If you don't want to do the work yourself send them off to him.
Anything you do to the front forks will be a huge improvement to the stock set-up. I think the stock forks are set-up for someone in the 130-145lbs range, very soft.
As mentioned, don't lower the fork tubes until you get a baseline set with the mods you did already. Only change one thing at atime. Try the new set-up and work off that. I put a 5mm shim in the rear shock instead of lowering the front fork tubes. Helped with turn in, put still was stable at speed. Lowering the forks may give you some unwanted head shake???
Good luck.
Anything you do to the front forks will be a huge improvement to the stock set-up. I think the stock forks are set-up for someone in the 130-145lbs range, very soft.
As mentioned, don't lower the fork tubes until you get a baseline set with the mods you did already. Only change one thing at atime. Try the new set-up and work off that. I put a 5mm shim in the rear shock instead of lowering the front fork tubes. Helped with turn in, put still was stable at speed. Lowering the forks may give you some unwanted head shake???
Good luck.
12-02-2007 | 04:31 PM
#6
Out of my mind, back in 5
MotoGP
Joined: Nov 2006
Posts: 6,109
From: Skurup, Sweden
Shim in the back and lowering tubes have the same effect, you get quicker steering and if you take it too far you get headshake in both cases... The only difference is that you loose/gain ground clearence and ride height depending on what you choose, and that's basicly it, tall riders shim, short riders drop the forks...
12-02-2007 | 07:15 PM
#7
Senior Member
SuperBike
Joined: Jul 2005
Posts: 1,548
From: MN
Was your question about changing the fork/height and new pilot powers to cpmpensate for differences in OD of the new tire vs. stock?
tweety, I thought rear ride height much more directly affected squat/antisquat, but a much smaller proportional change in steering angle, and that fork height was much more direct way of changing turn in alone?
tweety, I thought rear ride height much more directly affected squat/antisquat, but a much smaller proportional change in steering angle, and that fork height was much more direct way of changing turn in alone?
12-02-2007 | 07:31 PM
#8
Out of my mind, back in 5
MotoGP
Joined: Nov 2006
Posts: 6,109
From: Skurup, Sweden
cliby, changing the height of the tail end with a shim doesn't really effect the damper or spring characteristics, it just tilts the bike up and forward, changing the steering angle, same as changing the fork height, think about it... It's just basic geometric calculations...
But true you are also effectively lenghtening the back shock by a few mm, which probably effects squating, as it also changes the geometry of the back suspension...
Wichever is most effective is just a matter of measuring... biggest change in angle per mm is probably the front fork, but only slightly... and the downside is that you rather soon starts to grind stuff in the turns...
But true you are also effectively lenghtening the back shock by a few mm, which probably effects squating, as it also changes the geometry of the back suspension...
Wichever is most effective is just a matter of measuring... biggest change in angle per mm is probably the front fork, but only slightly... and the downside is that you rather soon starts to grind stuff in the turns...
12-03-2007 | 02:01 AM
#9
Thread Starter
Senior Member
Superstock
Joined: Jul 2007
Posts: 433
From: Los Angeles & Winston Salem
changes
Wow...well this thread came back to life!
Ok....1st off I purchased my hawk used with 1400 miles on it...the original owner had already stiffened up the front preload of the forks to max and lowered it about 4mm in the triples...being that I am on the lighter side I reduced the preload to 3 rings showing for street riding and on my recent trackday day 1 line showing with only half a turn out from max on the rebound.
This was ok for a super smooth racetrack...but we all know that the front fork springs are too weak for most people...also with them being progressive instead of straight rate,can cause other issue's.
I'm not a suspension expert.....so with my limited knowledge of rebuilding front forks...I installed .85 springs about right for my weight...7wt oil and lowered the air gap by 10mm...(AIR GAP>>this i did because my stock forks would bottom out really harshly over square edged bumps).
The 7mm figure I came up with for lowering the front forks seemed like a safe bet on from what I have read on this forum and others.....also when changing the front plush-o-matic progressive spring for some straight rate springs...the front end sits a little higher..from the bike not sagging on the weak springs...(I imagine you would have to lower the front quite a bit to compensate for this?).
I rode the bike today and all seems ok ...the front is better matched to the rear...no more soft front and stiff rear......I still have a compliant front end feel...a little less brake dive...but overall...the front does feel better.....also I would say that I could lower the front even more?....I think my next change will be a small shim on the rear shock...maybe 3mm or so..I think I would rather make small changes than huge drastic ones.
I'm really enjoying my ownership of this hawk.....so far the few changes I have made...have improved the bike...brake lines and ebc pads....pilot power tires....and removing all the smog and pair valve for some reason stopped my bike from running lean?....my bike never stalls now...and runs perfect fueling wise.
One question I do have is how much preload on the spacer is normal to run on this bike as my racetech springs were purchased used from a fellow superhawker (thanks again)....I have not set up the front end sag yet...but is feels like I may have just a little to much preload on the spring for street riding....I did not measure it when I installed them (duh I know) but my guessing is about 15-20mm (with preload adjusters backed out all the way).....the spacers I installed were 70mm long. The spring came with 2 sets of spacers one set 70mm the other 75mm, I think I may cut down the second set to 60 or 65mm and give that a try.....but will ride it the way it is for a few weeks 1st...just from my short 70 mile ride today it feels light the front sits ever so slightly higher and rebounds slightly faster?.....I know just fitting the springs and changing the oil is not the perfect cure for our superhawk but is a good improvement overall from the soft front progressive springs.
I have a another trackday planned for Jan 6th @ fontana speedway ama course... looking forward to trying out my new front end.
Ok....1st off I purchased my hawk used with 1400 miles on it...the original owner had already stiffened up the front preload of the forks to max and lowered it about 4mm in the triples...being that I am on the lighter side I reduced the preload to 3 rings showing for street riding and on my recent trackday day 1 line showing with only half a turn out from max on the rebound.
This was ok for a super smooth racetrack...but we all know that the front fork springs are too weak for most people...also with them being progressive instead of straight rate,can cause other issue's.
I'm not a suspension expert.....so with my limited knowledge of rebuilding front forks...I installed .85 springs about right for my weight...7wt oil and lowered the air gap by 10mm...(AIR GAP>>this i did because my stock forks would bottom out really harshly over square edged bumps).
The 7mm figure I came up with for lowering the front forks seemed like a safe bet on from what I have read on this forum and others.....also when changing the front plush-o-matic progressive spring for some straight rate springs...the front end sits a little higher..from the bike not sagging on the weak springs...(I imagine you would have to lower the front quite a bit to compensate for this?).
I rode the bike today and all seems ok ...the front is better matched to the rear...no more soft front and stiff rear......I still have a compliant front end feel...a little less brake dive...but overall...the front does feel better.....also I would say that I could lower the front even more?....I think my next change will be a small shim on the rear shock...maybe 3mm or so..I think I would rather make small changes than huge drastic ones.
I'm really enjoying my ownership of this hawk.....so far the few changes I have made...have improved the bike...brake lines and ebc pads....pilot power tires....and removing all the smog and pair valve for some reason stopped my bike from running lean?....my bike never stalls now...and runs perfect fueling wise.
One question I do have is how much preload on the spacer is normal to run on this bike as my racetech springs were purchased used from a fellow superhawker (thanks again)....I have not set up the front end sag yet...but is feels like I may have just a little to much preload on the spring for street riding....I did not measure it when I installed them (duh I know) but my guessing is about 15-20mm (with preload adjusters backed out all the way).....the spacers I installed were 70mm long. The spring came with 2 sets of spacers one set 70mm the other 75mm, I think I may cut down the second set to 60 or 65mm and give that a try.....but will ride it the way it is for a few weeks 1st...just from my short 70 mile ride today it feels light the front sits ever so slightly higher and rebounds slightly faster?.....I know just fitting the springs and changing the oil is not the perfect cure for our superhawk but is a good improvement overall from the soft front progressive springs.
I have a another trackday planned for Jan 6th @ fontana speedway ama course... looking forward to trying out my new front end.
12-03-2007 | 06:22 AM
#10
Out of my mind, back in 5
MotoGP
Joined: Nov 2006
Posts: 6,109
From: Skurup, Sweden
Then all seems good!!!
Well don't compensate for the sag of the soft spring... that's looking at it the wrong way...
With the correct spring set a correct static/rider sag, there are guides here somewhere... I guess you have done this already?
One thing to note is that the few mm you change in the front doesn't seem like much, but even small changes has enough impact for you to start grinding the header in full lean... And also to quick steering makes the bike very nervous in the front... If you have already dropped the front some 10mm I'd try the shim in the back first, as the changes kind of stack together...
Well don't compensate for the sag of the soft spring... that's looking at it the wrong way...
With the correct spring set a correct static/rider sag, there are guides here somewhere... I guess you have done this already?
One thing to note is that the few mm you change in the front doesn't seem like much, but even small changes has enough impact for you to start grinding the header in full lean... And also to quick steering makes the bike very nervous in the front... If you have already dropped the front some 10mm I'd try the shim in the back first, as the changes kind of stack together...
12-03-2007 | 08:07 AM
#11
Senior Member
SuperSport
Joined: Aug 2007
Posts: 599
From: Eagle, ID.
Speedkelly read this, https://www.superhawkforum.com/forum...ad.php?t=10021
to help you get your sag right, then adjust dampening.
Good Luck
to help you get your sag right, then adjust dampening.
Good Luck
12-10-2007 | 07:29 PM
#12
Administrator
World Champion
Joined: Dec 2004
Posts: 105,287
From: Fulton, MO
Internal preload should be 15mm. That means that:
- with the preload adjuster set in the middle of the range
- the spacer should be cut
- the fork all assembled except that the fork cap is loose and sitting atop the spacer
- fork fully extended (against the top-out spring but not compressing it)
You should have a distance of 15mm between the top of the fork tube and the lip of the fork cap.
- with the preload adjuster set in the middle of the range
- the spacer should be cut
- the fork all assembled except that the fork cap is loose and sitting atop the spacer
- fork fully extended (against the top-out spring but not compressing it)
You should have a distance of 15mm between the top of the fork tube and the lip of the fork cap.
12-11-2007 | 11:15 AM
#13
Thread Starter
Senior Member
Superstock
Joined: Jul 2007
Posts: 433
From: Los Angeles & Winston Salem
thanks
Yep...thats what I have...I took of the front end to check everything again....this is what I have 15mm of pre-load on spring via spacer....7wt fork oil (bel-ray)...85 springs.
After riding the bike for abit now I very happy with the springs....I ended up not dropping the forks so much put them back to just 3mm of drop....so almost to stock......at the moment I am just running with the pre-load on the spacer....fork pre-load adjusters backed all the way out.
This give me a pretty good ride.....I actually think after riding the bike for a bit that I could have gone even stiffer on the springs?....but this will propably be a good balance for track and street for me.
I think with the upgrade on the brakes and some springs my bike is really riding great right now....such a fun bike to ride....
Other than a rear shock (when one comes up) I think I will leave my bike alone and just ride it.
I really like it that my bike looks all stock, but can rock when needed to ...a little bit of street sleeper....so easy to ride in the twistys....and make a great track bike too....
Now if I had just not sat on that 2008 CBR1000RR at the bike show on friday.....???????????......thing fit me perfect....they even made the tank narrow.
After riding the bike for abit now I very happy with the springs....I ended up not dropping the forks so much put them back to just 3mm of drop....so almost to stock......at the moment I am just running with the pre-load on the spacer....fork pre-load adjusters backed all the way out.
This give me a pretty good ride.....I actually think after riding the bike for a bit that I could have gone even stiffer on the springs?....but this will propably be a good balance for track and street for me.
I think with the upgrade on the brakes and some springs my bike is really riding great right now....such a fun bike to ride....
Other than a rear shock (when one comes up) I think I will leave my bike alone and just ride it.
I really like it that my bike looks all stock, but can rock when needed to ...a little bit of street sleeper....so easy to ride in the twistys....and make a great track bike too....
Now if I had just not sat on that 2008 CBR1000RR at the bike show on friday.....???????????......thing fit me perfect....they even made the tank narrow.
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