1991 ST1100 Fork Seal Replacement

[Jrlyon]

I am going to do a fork seal and bushing replacement on my 1991 Honda ST1100.

If I should need springs, will a set of racetech springs with a stiffer rate drop right in? I don't want to do any pvc spacers or anything, I just want the springs to match the current springs in length, just a little bit stiffer.

Thank you,

Jim Lyons
STOC #9071

 

[TerryS]

Racetech springs are standard length/diameter/spring rate, but are not necessarily model-specific. They should come with PVC pipe for spacers, you will just need to cut these to length e.g. with a hand saw. RT provide instructions that allow you to work out the appropriate length.

 

[Uncle Phil]

Just a note - loosen the fork caps BEFORE you remove the forks from the triple tree.

 

[MV_Dave]

Another tip is to mark on the fork cap and tube where the threads start to engage. This helps when you are reinstalling the cap while compressing the spring if you know when the threads should engage.

 

[John OoSTerhuis]

Crack the bolt in the bottom of the slider next to the axle while it’s still mounted.

You probably won’t need to replace your OEM springs as they’ll most likely still be well within spec.

AOW: Fork Seal R&R Tips (ST1100)

John

 

[ST1100Y]

When assembling:
orientate the cuts of the bushings either inboard our outboard and mark the position of the fork tube (masking tape & Sharpie) before inserting them into the bottoms
(never have the cuts at the load bearing forward or rearward position)

 

[Jrlyon]

Crack the bolt in the bottom of the slider next to the axle while it’s still mounted.

You probably won’t need to replace your OEM springs as they’ll most likely still be well within spec.

AOW: Fork Seal R&R Tips (ST1100)

John

John,

On your tips it says to use a mechanical sissor jack under the engine. (Thats how I do it when I take off the front wheel)

Will the sissor lift under the engine give me enough clearance to remove the forks? I can only jack the bike up untill the rear wheel hits the ground, right?

When intalling the forks back into the bile, the manual says the top of the fork tube flush with the upper surface of the top bridge. Will I still have to do the axle thing that Bruce Triplett talks about?

Thank you,

Jim Lyons
STOC# 9071

 

[John OoSTerhuis]

Will the sissor lift under the engine give me enough clearance to remove the forks? I can only jack the bike up untill the rear wheel hits the ground, right?

Yes and yes.

When intalling the forks back into the bile, the manual says the top of the fork tube flush with the upper surface of the top bridge. Will I still have to do the axle thing that Bruce Triplett talks about?

Sorry, I don’t know who that is or what his tip entails but both tube tops should be flush with the top of the bridge.

John

 

[dwalby]

Will I still have to do the axle thing that Bruce Triplett talks about?

Not familiar with the name either, but if you're referring to the front axle tightening procedure that's commonly mentioned, yes you should follow that procedure.

 

[TerryS]

Regarding setting the fork height I like to set one tube per the manual and leave the second slightly loose, then check to see that the axle will slide cleanly without binding through both legs, and adjust the loose leg slightly up or down to achieve nice alignment (and then tighten it).

Getting the legs parallel on the axle is important for smooth fork action. One side is fixed (by the axle nut) and the other can float side-to-side a little until the axle clamp is tight. So tighten the axle nut, then bounce the forks up and down to let the other fork leg find its most relaxed position on the axle, then tighten the clamp.

 

[Andrew Shadow]

I don’t know who that is

Not familiar with the name either

He is a well respected suspension expert/tuner in the world of off-road motorcycles. I wasn't aware that he did anything to do with road bikes.

 

[ST1100Y]

One side is fixed (by the axle nut) and the other can float side-to-side a little until the axle clamp is tight. So tighten the axle nut, then bounce the forks up and down to let the other fork leg find its most relaxed position on the axle, then tighten the clamp.

Such could get religious as there is a marking groove on the LHS of the axle which should end flush with the outer edge of the LH fork bottom/clamp, indicating proper* alignment...
*as long as all wheel bearings have been installed as instructed too...

 

[Uncle Phil]

Sort of interesting to me - I've never bounced the front forks in 470,000+ miles of ST1100 tire changes across 4 ST1100s.
I just install the wheel, tighten the axle nut first to 65lbs, then the pinch bolts to 16lbs and call it good.

 

[sky.high]

I've 'bounced' mine all the way home from a dealer who hadn't bothered to retighten them, felt fine to me !!!!

 

[TerryS]

I've 'bounced' mine all the way home from a dealer who hadn't bothered to retighten them, felt fine to me !!!!

I rode my brand-new Suzuki RF900 home from the dealer and thought I had bought an ill-handling pig. The phrase "handled like a wheelbarrow full of wet cement" came to mind. Turned out, that is what you get with 9psi in the front tyre. The same dealer later left the oil filler cap loose after the first service whichI only discovered after it had pumped a decent quantity out over my boot and the right rear of the bike. Dealers are not to be trusted.

 

[Jrlyon]

Yes and yes.

Sorry, I don’t know who that is or what his tip entails but both tube tops should be flush with the top of the bridge.

John

John,

On the left fork leg assembly, step (11) is installing the socket bolt/washer. After you install the socket bolt/washer do you then torque it to 14 FT LBS or do you wait to torque these bolts after the fork legs are completely done? I know you torque the fork caps after the forks are back on the bike.

Will I be able to grab the damper rod on the right fork with just a 33 inch coat hanger with a loop on one end? Are the 10 MM bolts and nuts fine thread or super fine thread? See image below.

I have a Motion Pro ringer style fork seal driver. Will I be able to drive the upper bush and seal in without removing the the fork tube protector from the slider? I know I could do it with the pvc pipe and the two hose clamps washer and cap. What size pvc did you use, was it 2 Inch?

I just completed a Buell XB12R fuel pump rebuild successfully. I had to take the swing arm off per the manual and had it done and riding the bike after three days. It was pretty cut and dried, just hate messing with flare fittings, but really no proble with flare wrenches. Rebuilding the pump was lind of sketchy with a hard plastic flex like that you had to heat up with heat gun the slip it on and clamp it with a and ear clamp.

Jim Lyons
STOC #9071

 

[John OoSTerhuis]

On the left fork leg assembly, step (11) is installing the socket bolt/washer. After you install the socket bolt/washer do you then torque it to 14 FT LBS or do you wait to torque these bolts after the fork legs are completely done? I know you torque the fork caps after the forks are back on the bike.

Jim, it may spin if you try to torque it then. I’d say snug it up so suspension fluid doesn’t leak past and wait until the fork is mounted again to do the final torque. Just like during disassembly, loosen that bolt while the forks are still mounted. Torque the fork caps with the upper bridge bolts loose, and crack them during disassembly similarly.

Will I be able to grab the damper rod on the right fork with just a 33 inch coat hanger with a loop on one end?

Probably. Have a look at the included pictures of damper tools.

Are the 10 MM bolts and nuts fine thread or super fine thread? See image below.

Super fine, as noted in the picture.

I have a Motion Pro ringer style fork seal driver. Will I be able to drive the upper bush and seal in without removing the the fork tube protector from the slider?

I don’t know, what does it look like? The Honda special tool drivers in the STOC loaner tools kit don't require removal.

I know I could do it with the pvc pipe and the two hose clamps washer and cap. What size pvc did you use, was it 2 Inch?

Sorry, I don’t remember and I threw my DIYer away. You have to have an ID of ~> than 41mm or 43mm, depending on your year and model. I know I had to cut slits in the PVC and use a hose clamp to reduce the diameter to get a snug fit.





John

 

[John OoSTerhuis]

BTW, here’s an often overlooked check while reinstalling the front wheel (from the Owner’s Manual):



Comments from the peanut gallery…?

John

 

[ST1100Y]

Comments from the peanut gallery…?

like: don't forget to pump up them brakes before even attempting to roll it off the main-stand...

I check quite a number of things while the front end is lifted/me working on it...
- head bearings
- visuals on various parts (corrosion, wear, cracks, leaks...)
- waterproof grease behind the bearing seals
- wheel bearings
- clean/grease the speedo gears (not too much though)
- speedo cable (sleeving cracked, proper routing, etc...)
- rotors, calipers & pads
- while spinning the wheel I check for irregular noises and test for prompt grip and prompt release...
- tlgo

 

[John OoSTerhuis]

I have a Motion Pro ringer style fork seal driver. Will I be able to drive the upper bush and seal in without removing the the fork tube protector from the slider?

don’t know, what does it look like? The Honda special tool drivers in the STOC loaner tools kit don't require removal.

Fork slider and seal drivers pictures are in the tool loan article (register):
(STICKIE) ST1100[/ST1300] Fork Seals R&R Tool Kit