Article [13] ST1300 - Pre-load Fluid Replacement

Add my name to the list of people who have successfully performed this fix; all due to the time and patience of those who contributed their efforts.

Just finished the service. Super easy removing only the one bracket bolt. My adjuster knob was rather clean so I didn't bother removing it.

I used hydraulic jack fluid from the hardware store. It looked the same color and viscosity as the oil I drained out of the adjuster.

Thanks for the instructions!!

Did it yesterday. Did it on the left hand side of the bike. Lost the detent ball! Ace Hardware had one! Took the banjo bolt out and tucked the hose up high so it didn't drain out. Drained the cylinder and pushed the piston back. Refilled it and it took 10 ml of 5W Honda fork oil I had on the shelf. Resistance within the first 1/2 turn!
Thanks

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Thanks for such a helpful article and thread. Curious, can I use ATF or jack oil for the reservoir?

maverickfhs said:

Thanks for such a helpful article and thread. Curious, can I use ATF or jack oil for the reservoir?

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I don't think it matters much which you use. Over the years in this forum and in the Goldwing forums I am now following, people used both hydraulic jack oil and fork oils of various viscosities with good results. In my 1981 BMW ATF was a popular oil to use in forks so I guess it qualifies.

Igofar said:

I have found an even easier short cut! Instead of removing the knob, spring and detent ball, then removing the (2) 10mm bolts, unclipping the line from the fender, loosening the rear master cylinder bolt, and feeling the whole assembly over to the right side etc.....

New improved method:
1. Remove left side cover
2. Observe how the unit is bolted on
3. Instead of removing the 10mm bolts, follow the mounting bar upwards to where it bolts to the frame by the lift handle. You'll see (1) 10mm bolt. simply remove this one bolt, and gently pull the line free from the front of the rear fender. You can then simply turn the entire unit upside down on the left side of the bike without removing anything else. You now have a bar to hang onto while you loosen the banjo fitting. As far as having the line point in the correct position, I simply observe where it was before you loosen it, or mark it with a sharpie. I can now R&R one of these in about 10 minutes! Hope this helps.

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Thanks for the instructions. Just did this on my '05 and it made a big difference. Ride is much better. Is there anything we can do to make the front suspension a little more plush?

MNKid said:

Thanks for the instructions. Just did this on my '05 and it made a big difference. Ride is much better. Is there anything we can do to make the front suspension a little more plush?

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Did you have to remove the plastic panel for clutch side to access that single 10mm bolt? Thank you

maverickfhs said:

Did you have to remove the plastic panel for clutch side to access that single 10mm bolt? Thank you

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Not so much to take out the bolt but to get the preload adjuster and its support bar out you will need to remove the body panel.

MNKid said:

Not so much to take out the bolt but to get the preload adjuster and its support bar out you will need to remove the body panel.

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Finally getting to it, anyway you could share a pict of bolt(area) which needs to be removed? Anyways, I'll be removing body panel to charge the battery up. Thank you

MNKid said:

Not so much to take out the bolt but to get the preload adjuster and its support bar out you will need to remove the body panel.

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Why are you removing the support bar? There are 2 bolts with 10mm heads that hold the adjuster to the bar. That is all that needs to be removed. It is easier to get to everything if you remove the body panel on that side, but not totally necessary.

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I refilled the preload adjuster on my '09 about 5 yrs. ago. I used this thread as a guide then. It's time to refill again.

There are usually torque specs for the banjo bolts on brake plumbing. I've re-read the entire thread, and have not seen a torque spec for the preload adjuster banjo bolt.

I've got two questions:
1) Does anyone know the correct torque for the banjo bolt?

2) Someone posted a thread long ago in which the preload adjuster collar at one end of the shock's spring was disassembled to determine why preload fluid was disappearing to begin with. The collar is what is acted upon by pressure changes in the preload adjuster mechanism itself to actually change spring preload. IIRC, the spring preload collar assembly at the top of the shock that consists of a ring-piston within a ring-cylinder. Movement of the assembly's piston acts upon one end of the spring to change preload by varying its at-rest (rear tire off the ground) compression (preload). The author of the thread posted pics of a large O-ring in the collar's cylinder that becomes compressed or worn, allowing preload fluid to gradually weep out of the adjuster system, resulting in loss of travel. I've been unable to locate that thread. Anyone know where to locate it?

Good Ridin'
slmjim

My pet theory is the rubber hose expands over time because the adjuster is left under pressure and the additional volume within the expanded hose takes up the 'missing' fluid. I keep a very clean bike and I never ever noticed a weep, seep, or leak on any of the components. OTOH when one is filled it takes just a few ccs of fluid to top up and regain all the travel again.

FWIW I made it a rule to always turn the preload to zero when the bike sat more than a day or two and I never had to add fluid since the last time it was done - about 100,000 miles ago but prior to that it lost 9 turns in 75,000 miles.

I had the opportunity to take apart the adjuster for the preload assembly. The surface finish inside of this unit is crude at best. Lots of scratches and swirl Mark's that the fluid can leech out off. No exactly wha I would have expected from Honda. I decided to do some polishing of this unit to see if I could lessen the fluid loss. It has helped dramatically. I only lose about a 1/8 of a turn each year.

To take this unit apart though requires that you drill a hole inline with the end of the C-clip. Then the c-clip can be removed by pushing it out of the groove. Trying to remove it otherwise is next to impossible.

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slmjim said:

I refilled the preload adjuster on my '09 about 5 yrs. ago. I used this thread as a guide then. It's time to refill again.

There are usually torque specs for the banjo bolts on brake plumbing. I've re-read the entire thread, and have not seen a torque spec for the preload adjuster banjo bolt.

I've got two questions:
1) Does anyone know the correct torque for the banjo bolt?

2) Someone posted a thread long ago in which the preload adjuster collar at one end of the shock's spring was disassembled to determine why preload fluid was disappearing to begin with. The collar is what is acted upon by pressure changes in the preload adjuster mechanism itself to actually change spring preload. IIRC, the spring preload collar assembly at the top of the shock that consists of a ring-piston within a ring-cylinder. Movement of the assembly's piston acts upon one end of the spring to change preload by varying its at-rest (rear tire off the ground) compression (preload). The author of the thread posted pics of a large O-ring in the collar's cylinder that becomes compressed or worn, allowing preload fluid to gradually weep out of the adjuster system, resulting in loss of travel. I've been unable to locate that thread. Anyone know where to locate it?

Good Ridin'
slmjim

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Found it:

https://www.st-owners.com/forums/index.php?threads/pre-load-oil-leakage-fixed.154060/

Did mine tonight. 15' took my time. was at 21 clicks to get any kind of resistance. now at 2 clicks for resistance.
Drained 5ml of light gold fluid replaced it with 15ml of SS8 fork fluid. By my calculation it lost 10ml of fluid over the last 135,450 miles.

Great help guys!!! Just did mine this morning. This info, along with a video posted on the Honda ST1300/ST1100 Great Ride Group Facebook group, , made it very easy! Blessings!

Did mine this afternoon and received the same good results. Once I finish the other maintenance items on my list, learned through all the first rate experience everyone shares here. I don't think I could have attempted much of what I've done to improve and maintain this bike without all your help.
So, thank you all.

I did the full shock and preload removal. its just me.... cleared the line, fooled around with the adjustment clip for about 5 min the i had a thought. ( previous thread if i read all of this thread) I drilled the preload housing to remove the spring clip. WHY THE HELL did they not use a snap ring with holes here i will never know.

I reassembled the hose and the preload housing. I added ATF fluid , added the piston (had to adjust the oil level to get it in the right place) and then adjustment assembly, I placed the prelaod assembly in a vice added a little pressure to get the snap snap ring in. I now have zero air in the system and immediate actuation of the preload. i can't wait to get in this.

anyone know in mm how much preload is achieved by added preload to the spring via the adjuster?

I have the shock in preload under load looking for any leaks. I'll get a measurement of my spring preload (appears to be around 3/8") along with some pictures

Congrats on doing your preload adjuster. You will notice a big difference with that.

that with my zx14 fork springs.