Fork spring replacement without removing the forks??

CruSTy

CruSTy

My Perception is my reality.
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Joined
Jun 30, 2013
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502
Age
72
Location
Paola, Kansas
Bike
2007 ST1300A
Anyone tried this. I have some new springs and shop manual. No reference to replacing the springs without removing the forks. Looks like it could be done. Seals and bushings are good and only 16k miles so I see no need to replace the oil and seals unnecessarily. There is room to remove the cap (no riser issue) without removing the fork from the bike. Has anyone tried this??
 
couplers said:
Anyone tried this. I have some new springs and shop manual. No reference to replacing the springs without removing the forks. Looks like it could be done. Seals and bushings are good and only 16k miles so I see no need to replace the oil and seals unnecessarily. There is room to remove the cap (no riser issue) without removing the fork from the bike. Has anyone tried this??
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The cartridge fork is much easier to work on when its off the bike. You'll need to compress the spring a bit to remove a retaining clip before you can get the spring out, its easier to do that with the fork vertical and in front of you at floor level.
 
You can change the springs spring without removing the forks. You can also pull the cartridge and change the oil by removing the socket head bolt under the front axle.
 
zooker13 said:
You can change the springs spring without removing the forks. You can also pull the cartridge and change the oil by removing the socket head bolt under the front axle.
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Thanks,
That's the answer I was looking for. That's what it looked like in the exploded view in the manual. I will give it a shot.
 
dwalby said:
The cartridge fork is much easier to work on when its off the bike. You'll need to compress the spring a bit to remove a retaining clip before you can get the spring out, its easier to do that with the fork vertical and in front of you at floor level.
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Sorry forgot to mention it is a 2007 1300. No clip.
 
Yes it can be done. I did it several time while trying to figure out which spring to go with. The one thing to keep in mind though is that with a stiffer spring in there the oil level does not need to be as high. The factory setting runs a higher oil level, thus smaller air pocket to help with the light weight springs. I believe the stock oil level is 65mm from top of the fork when totally compressed. Most of the aftermarket spring companies recommend 135mm. The higher stock oil level will give you a harder ride. The trapped air pocket acts as a secondary spring. The smaller the high pocket the faster it compresses and raises the air pressure.
 
mlheck said:
Yes it can be done. I did it several time while trying to figure out which spring to go with. The one thing to keep in mind though is that with a stiffer spring in there the oil level does not need to be as high. The factory setting runs a higher oil level, thus smaller air pocket to help with the light weight springs. I believe the stock oil level is 65mm from top of the fork when totally compressed. Most of the aftermarket spring companies recommend 135mm. The higher stock oil level will give you a harder ride. The trapped air pocket acts as a secondary spring. The smaller the high pocket the faster it compresses and raises the air pressure.
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Thanks,

Excellent point. Ill definitely be checking the relative oil level. Though it Might be hard to measure accurately with the forks installed. I can get close though and can make both sides the same.
 
It's not that hard to remove the forks....at most an hour or two...I don't think you will end up saving much time unless you've done a fork oil change a few times and know what you are doing. The handlebars overhang the fork caps, it's going to be tight getting the caps off the damping rods, old oil new springs.
 
dduelin said:
The handlebars overhang the fork caps
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I believe some of the bikes with aftermarket risers have a clearance issue. Mine appear to be clear of the caps and don't overlap.
fork cap.jpg
 
couplers said:
I believe some of the bikes with aftermarket risers have a clearance issue. Mine appear to be clear of the caps and don't overlap.
fork cap.jpg
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I don't have risers I guess that's only an issue [caps clearing the bars] with stock set ups. I'd still drop the forks to clean out the cartridges and replace the old oil but I do it every 15 or 20,000 miles. At 16k it needs to be done to fully understand what the new springs provide. Just my 2 cents.
 
Previous bike I had to "pump" out the oil while holding the fork upside down...compress the forks several times.....just draining it wasn't enough. This the case with the ST forks?
 
jonjonboo said:
16,000 miles---- I would remove the fork assembly for ease of flush and fill of fork oil. New after market springs will have directions on how much oil---good idea to watch a few instructional videos on replacing fork oil and why that is so important
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dduelin said:
It's not that hard to remove the forks....at most an hour or two...I don't think you will end up saving much time unless you've done a fork oil change a few times and know what you are doing. The handlebars overhang the fork caps, it's going to be tight getting the caps off the damping rods, old oil new springs.
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Looks like at the very lease I will be replacing the oil along with the springs. May still try to remove the cartridges with the forks in the bike and while I can still drain all the oil is doesn't look like I will be able to accurately check the oil level on refill. Looking more and more like fork removal time.
 
You have to remove the front tire to get to the bolt to remove the cartridges. At that point you might as well spend a half hour more to do it right.
 
Thanks all!! Forks have been removed. New Sonic 1.2 springs installed and new 7wt oil filled to 125mm. Climbing on the bike I noticed immediately the static sag was less. I estimate it was nearly 48-50m with the old springs. Now it is around 32mm. After bouncing the front end a couple of times I immediately noticed less suspension travel. I was getting concerned initially that the 1.2 springs might be too stiff. I rode to an area near by that had some pretty rough bumps. I cringed as I approached the first big one expecting to get my teeth rattled. Man was I surprised. No thump no whump no jolt. Even with single rider (usually 2up) and only 2 gallons of fuel it took the bump like a champ. Next I tested for nose dive under braking. I think previously the stock springs were allowing the front end to bottom out. Nose dive was significantly reduced and much more important under very hard braking the suspension didn't seem to bottom out. The are just my initial impressions. I ll report back after a bit and let you know how I like this setup after riding for a couple of weeks.
 
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How does 7wt. fork oil compare to whatever fish oil ships with the bike? Is it a heavier oil?
 
Not sure what your weight is, but I found the 1.2 to be a little to stiff. I weigh 170. I started with the 1.2 and ended up with .90. Thus my earlier post about changing out fork springs many times.
 
mlheck said:
Not sure what your weight is, but I found the 1.2 to be a little to stiff. I weigh 170. I started with the 1.2 and ended up with .90. Thus my earlier post about changing out fork springs many times.
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6'3 225# without gear and 80% 2 up riding. I think I could use some more damping but this is definitely a + improvement.
 
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