Front shocks removal

Kevcules

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I've read a lot on here about removing the front shocks and taking them apart, but it gets more clear after you do it.

My front shocks seemed really stiff when I'm driving my new to me ride. So I decided to take them apart and see whats inside. I've attached some pics of the fork parts and was wondering if anyone can tell me if they are OEM or not.

I checked my sag before doing this and hoping I did it right. My young son was helping so the numbers might be off a little.
Front - no weight (jacked up) then I measured the difference with just the bike weight and got 45mm difference. Then with me on the bike it measured only another 6mm less.

Rear - same set up - I measured 5 mm difference from no weight and then just the bike weight. Then with me on it , it went down another 21mm. The rear shock seems to work better since I lowered the pre-load setting. I understand though that I should have more like 30 mm of sag right?

The springs came out with the closer coils "down". I thought I read that they should go in the "up" position?

I may need some sonic springs set up for my weight (172 ish) What options do I have with my current set up other than getting different springs and spacers?

Thanks
 

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Kevcules

Kevcules

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I measured 249-250 mm for the spring and 199-200 mm for the spacer. (springs and spacers from left to right are identical)

Spring length limit is 244.6 mm as per the manual.
 
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Those are stock OEM springs and steel spacers.
After trying sonic 1.2 springs and finding they were WAY too stiff for me (225lbs) I replaced them with 1.1 springs, 7 weight oil, 125mm from top when compressed, and 140mm PVC spacers.
Much better.
YMMV
 
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The perceived stiffness of forks has much to do with the damping as well as the springs. In addition to putting in some weight-specific springs, you can modify the dampers to change their characteristics. A little file work and some spanners are all you need tool-wise. A common change is to fit RaceTech Gold Valves in place of the standard valves, and apply shims to suit. The stock valves look to be typical Honda HMAS valves which have small (restrictive) ports which will tend to make for a harsher response to bumps. Gold Valves and their ilk have much bigger ports and flow oil faster on big hits, and take a lot of the shock out of bumps, while still giving a controlled ride.

I'm using 0.9 kg/mm springs on my ST1100, I tried 1.1 kg/mm springs and they were too harsh for me, riding solo and with no luggage.

BTW, progressive rate springs should have the tight coils to the bottom.
 
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Wow, having never owned a 1300 I am shocked to see spacers that are almost as long as the springs, I have never seen that before.

agree with TerryS comment about damping and stiffness. I had a sportbike with fully adjustable forks and I could make the ride get harsher just by cranking up the rebound damping adjustment screw, without touching the spring preload at all. Changing spring preload influences other fork parameters, so there's a lot of time spent on trial-and-error setting up suspensions without external adjustments.
 

dduelin

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........I may need some sonic springs set up for my weight (172 ish) What options do I have with my current set up other than getting different springs and spacers?

Thanks
The only change you can do without changing springs and spacers is to change oil properties but it's not hard to get the sag right by changing spacer length. You are about 10 lbs heavy for the stock springs but you could just try adding some 15 mm or so extra preload to the stock set up to get the sag to 36 - 40 mm. Cut and install PVC spacers about 215 mm long with a 5 to 7 weight oil to a level of about 65 mm. This will raise the ride height to get the fork working the middle 1/3rd of it's travel and remove some of the harshness felt in quick, rapid compressions. The stock spring has a rate of .860 (kg/mm). At 172 lbs you likely need a rate of .9 kg/mm. Sonic springs at 1.1 are probably stiffer than optimal for your weight.


Fork oils do not fall cleanly into a description of their damping properties by using the term "weight". Some brand 5 weight oils act or feel like 7.5 or 10 wt oils of another brand. To keep the damping properties relative to the OEM action and to each other try to use Honda fork oils for experiments. The stock oil is SS-8 which could be described as 10wt. Honda SS-7 could be described as 5 weight. Using a 50/50 mix of SS-8 and SS-7 would be 7.5 weight relative to the OEM fork set up. Using 100% SS-7 would be 5 wt. This makes oil change properties easier to predict and duplicate.
 

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The only change you can do without changing springs and spacers is to change oil properties but it's not hard to get the sag right by changing spacer length. You are about 10 lbs heavy for the stock springs but you could just try adding some 15 mm or so extra preload to the stock set up to get the sag to 36 - 40 mm. Cut and install PVC spacers about 215 mm long with a 5 to 7 weight oil to a level of about 65 mm. This will raise the ride height to get the fork working the middle 1/3rd of it's travel and remove some of the harshness felt in quick, rapid compressions. The stock spring has a rate of .860 (kg/mm). At 172 lbs you likely need a rate of .9 kg/mm. Sonic springs at 1.1 are probably stiffer than optimal for your weight.
I've been here and done this and it definitely is a improvement over the stock set up. dueling is correct about the springs being a little light, but I'm in the same weight range as you and the stock springs worked well with the proper preload and oil level. The oil level he suggests is not the stock level as Honda uses the air trapped in the fork as a secondary spring to make up for the low preload settings. This is a quick and easy way to improve the forks. You are looking for 36-38mm of sag with the rider when done.
 
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Kevcules

Kevcules

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ok....thanks for the responses. This suspension setting is all new to me.

I'll probably just try to adjust what I have now to get it better for me. I'm surprised that increasing the length of the spacer (more pre-load) and different weight oil will improve the ride for me.
So I now have 51 mm of sag and I'm looking for about 36-38 mm right? I'll give these suggestions a try soon but won't know the riding results until the spring. It's down to 4 degrees celsius these days... (39 F)

Will increasing the front preload increase my ride height? Roughly how much? Could I raise the fork height in the clamps a little to offset that?

thanks
 
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dduelin

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ok....thanks for the responses. This suspension setting is all new to me.

I'll probably just try to adjust what I have now to get it better for me. I'm surprised that increasing the length of the spacer (more pre-load) and different weight oil will improve the ride for me.
So I now have 51 mm of sag and I'm looking for about 36-38 mm right? I'll give these suggestions a try soon but won't know the riding results until the spring. It's down to 4 degrees celsius these days... (39 F)

thanks
Adding preload doesn't change the stiffness of the spring contrary to intuition. It raises the ride height and increases the amount of force necessary to compress the spring but once the spring begins to compress the stiffness is the same. In practical terms adding preload and a thinner oil viscosity keeps the fork from bottoming out and makes the action a little more soft on hard, fast bumps. Too thin on the oil however and the rebound damping suffers and becomes too fast. In my bike I like to use a 2:1 mix of Honda SS-7 and SS-8 to arrive at 6.7 wt compared to OEM 10wt. The spacers are 216mm long. I did this over 100,000 miles ago on my 2005 ST and I've been very happy with it. My sag is 36mm. I change the oil and flush out the forks every 15 to 20,000 miles. New oil makes a difference too.
 
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Kevcules

Kevcules

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thanks

I think I'll go for the same or similar mix with an increased spacer length. I don't really understand it yet, but sure believe you guys.

Does 1 bottle of fluid do 1 fork?

thanks
 

dduelin

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thanks

I think I'll go for the same or similar mix with an increased spacer length. I don't really understand it yet, but sure believe you guys.

Does 1 bottle of fluid do 1 fork?

thanks
It takes two 16 oz bottles and a partial 3rd bottle of Honda SS 8 to change out at the stock level. 2.7 bottles if I recall correctly.
 
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It takes two 16 oz bottles and a partial 3rd bottle of Honda SS 8 to change out at the stock level. 2.7 quarts if I recall correctly.
The service manual states 638mL per leg for a standard fill. So two litres would be plenty even with a higher oil level.
 

dduelin

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The service manual states 638mL per leg for a standard fill. So two litres would be plenty even with a higher oil level.
Honda sells it in 16 oz / 473 ml bottles. I corrected my post to amount of bottles instead of quarts.
 
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Kevcules

Kevcules

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ok thanks guys. I'll have to wait until the weekend to get some oil, my local dealership is closed on mondays...

I need some 1.5" PVC too.....
 
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ok thanks guys. I'll have to wait until the weekend to get some oil, my local dealership is closed on mondays...

I need some 1.5" PVC too.....
You must live in a more advanced country than I do. All the mc dealers close at 3pm Saturday and reopen Monday morning. I've never understood the logic of that when the customer base is most active on Saturday and Sunday. [emoji849]


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Kevcules

Kevcules

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You must live in a more advanced country than I do. All the mc dealers close at 3pm Saturday and reopen Monday morning. I've never understood the logic of that when the customer base is most active on Saturday and Sunday. [emoji849]


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Yeah, I agree. Mine is closed on sunday and monday , but open from 9am till 1pm on Saturday.... They close at 5:30 during the week but that makes it too hard to catch them after work....
 

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thanks

I think I'll go for the same or similar mix with an increased spacer length. I don't really understand it yet, but sure believe you guys.

thanks
Adjusting the suspension is a bit of a black art. The Internet is full of useful information. Do yourself a favor and do a little reading before you dive in. dduelin and myself have done allot of modifications and reading. We won't steer you wrong, but please do some research so that you understand what we are trying to explain to you.

What works for one guy, may suck for somebody else. Also be aware that rider weight and wether you ride 1 up or 2 up has allot to do with your suspension setup.
 
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Kevcules

Kevcules

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Got some SS8 fluid today. The dealership said they don't carry any other weight? They sell Honda and Harley Davidson there. So I'll try the 10 weight oil. It's dark red and the stuff I poured out wasn't red. I wonder what weight was in there?
Also having a hard time finding some PVC pipe. I checked two hardware stores in the last week including Home Depot and nothing small enough. I need 1.25 inch ID ,to get the 1.5" OD right?
I ordered two new drain bolts and washers and they should be in by the weekend. Today was about 10 degrees Celsius (50F) , I could have driven today if the bike was ready......
 

dduelin

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I can't speak for your dealership but Honda sells several other types of suspension fluid and they might have to order SS-7 for you or you could order it online from someone else. Fluid turns dark and gunky in use so if the old fluid will look nothing like new fluid. SS-7 is almost clear.

A PVC sink tailpiece is exactly the OD needed and every plumbing store carries them. The wall thickness of a tailpiece is shockingly thin but they are plenty strong in the ST1300 forks. The ones I made have been in use over 100,000 miles.
 
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