Article [13] ST1300 - fork seal replacement and sonic spring installation

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My right fork seal began leaking during our most recent trip. Attempts at cleaning out any debris with a Risk Racing Seal Doctor, while a nice tool, was unsuccessful.


Time to replace the seals after only 110,000 miles on the original OEM seals. There is lots of information here on ST suspension, really an overwhelming amount, and after lots of research and a call to Mellow I finally decided to replace the OEM springs with a set of Sonic springs while I had the forks apart. The Sonic springs come with lots of positive reports and for $79.95 plus $13 shipping I thought they were worth a try. I did have a sense that the front end was a little soft.

There are lots of good tips on seal replacement and the service manual is actually very good. I just wanted to add a few pictures, a few suggestions and and my Sonic springs installation numbers.

There are excellent pictures here.
https://picasaweb.google.com/116177976159614867888/ForkSeals?authkey=Gv1sRgCN6t6cbsmrTogwE#

My contributions:

Here is the problem when risers are installed as many of us have, you cannot remove the caps or get to the caps to remove them without either removing the risers or dropping the forks down lower.




Here are the lower fork clamp bolts, easy to see and loosen with the Tupperware off.



Now with the fork down and reclamped with the lower bolts tightened you can easily get to the cap. The cap definitely needs to be loosened while in the fork clamps as it may be very tight.




Here is the 17 mm Allen socket in the cap.



Now you can get a 17mm wrench on the socket and even a cheater bar if needed, the Tupperware will need to be off for this technique. Alternatively an extension on the 17mm socket may give adequate access from above.



Here is the fork removed.



Now to get the fork apart.




Following the book at this point is really very good.

A few other tips, the 1 1/2 PVC coupler needs to have the center stop/ridge removed so that it slides easily on the fork. A drimel tool works well for this.



Here is the modified driver( the 1 1/2" coupler ) and the hammer, a 16" piece of 2" PVC. These allow setting the new seal without any problem.
Put some fork oil on all sides of the new seal and it will slide right in.



Here is the Saran Wrap trick to get the new seal on without damage.



Now for my Sonic springs numbers. I weigh about 175# so I choose a 1.1 spring. The Sonic suggestions were for a spacer of 130 mm and fork oil of 125-130mm. I have apparently lost my metric tape measure so I used 5 1/16" spacer (about 129mm). I used one of the washers that came with the springs between the spring and the spacer and choose no washer on top with the spacer resting against the cap itself.



Here is my tool for measuring my oil level, I choose 130mm, the little circle at the bottom allows you to see when the wire just reaches the oil.



Hopefully these pictures along with all the info on this site will help the next owner get it done.
 
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OP
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Re: ST1300 another fork seal replacement and sonic spring installation thread.

Thanks Jim, pictures always help me.

Oh, I forgot to mention the results. I haven't ridden enough to give a detailed report but here is what I have noticed so far. As I told Mellow I really didn't have much complaint about the OEM springs just a sense that they were a little too soft, but I didn't want a drastic change. These current springs and oil resulted in exactly what I wanted, just a little stiffer than OEM. The best part is with hard braking, very little dive. I had done some work on the brakes at the same time so on the test ride I wanted to test both. On the first hard stop I thought there was something wrong with the brakes, maybe air in the lines. After multiple hard stops I finally realized that the brakes were stopping just fine but what I was missing was the hard dive that I had gotten use to with the ST. It was now gone...Wow, that is really nice. I really think it is a safety issue as I am sure the bike is now much more controllable in a hard stopping situation. This would be very noticeable two-up. I would strongly suggest the new springs to anyone that is going to the trouble of replacing the fork seals or oil....
 

Mellow

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Re: ST1300 another fork seal replacement and sonic spring installation thread.

Great write-up Jeff, I moved to the Article section.
 

okckeith

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Re: ST1300 another fork seal replacement and sonic spring installation thread.

Thanks for the write up Jeff. I just ordered Sonic springs yesterday. I have a seal leak on the left side. Now If I can get some time off to do the job.
 
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Nice job, fellow sonic spring user. :) my results were the same; less dive, much better front end feel... Great improvement for such a relatively cheap modification. I gave up on breaking the top 17mm hex with the fork on the bike, I removed the forks and hit them with my 1/2 drive air impact hammer. http://jasonfj.blogspot.com/2013/08/stick-fork-in-me_9654.html

Sent from my SPH-L710 using Tapatalk
 

okckeith

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Is this the right seal # for my 2007 ST1300? (51490-MCA-003) seal set FR. Fork? And is this a set of two? And do I need two of (91356-MWO-003) O-Ring 37.2 X 2.4?
My springs showed up today. They got here in less than 48 hours. Now if I can get some time off.
Thanks for your help.
 

Throttlejockey

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You don't need to replace the o-rings if you're referring to the fork cap.
Each seal comes with the wiper as a set so you'll need 2 seals.
 

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I just discovered my seals are leaking, thanks for the tips.
 

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I had the same problem with the risers Jeff. I removed the fork completely and used an electric impact holding the fork by hand and the caps backed right out.
 
OP
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Glad that worked for you. I just recently changed one of Lynne's seal and used the drop down and re clamp method without problem. As long as they come off that's all that maters.
 
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Ok. Ok. Ok. Ive seached and searched and have a very good grip on doing this fork change. Thanx to all the wise people. Can someone please explain the "saran wrap trick"? Im not quite understanding how much wrap to apply and Im assuming you pull it out as you drive the seal in. Thanx in advance.
 

Throttlejockey

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The saran wrap just protects the seal when you slide it over the tube.
 
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Exactly. Just need enough to cover the end and stay on. The seal should slide past it then you take it off.
 
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Thanx guys. I think Im ready for the rebuild. Sonic springs, seals, butchings, 7.5 oil, wheel bearings while Im at it and should fix the "washboard" affect. Great write up very helpfull. Oh btw the odometer only goes to 200k then starts over, so I have a new old bike with about 2k on it. I know its wrong but it looks/feels nice. ; )
 
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My fork seal was leaking and I wasn't real happy about the front end dive the ST1300 has. Sorry I was busy so I took it to the STealer to have the seals changed and change out the factory springs with Sonic Spring 1.1 rating. I am a big boy at 250lbs. I am happy with the stiffer front end but would recommend if you are lighter using a lower spring rate. I feel the expansion joints more now but the front doesn't travel up and down with the throttle being applied or let off. They are also stiffer in braking. I don't ride hard always have chicken strips love the better handling that I now have.
 
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The seals on my 06 were leaking so I ordered replacements and a set of Race tech 1.0 which were recommended for my weight. I got the seals in ok but I'm not sure how to finish the rebuild with the extra washers Race Tech provided. What is the order to reassemble the spacer, spring and washers? The new springs are about an inch and a half longer than the stock Hondas. I was hoping to use the stock spacer rather than cutting pvc.
 
OP
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Not sure about the washers. I would follow the manual as much as possible. With the longer spring you will need the PVC spacer. It works just fine.
 
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I don't have a manual but I think it came apart as spring, washer, and then spacer. I was wondering what would be the problem using the stock spacer.
 
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