St1100 2000, Fork Oil Volume and depth from Honda Manual

Joined
May 30, 2007
Messages
1,387
Age
72
Location
Grand Junction, Colo.
Bike
92 ST1100
Excellent! Glad you are back on the road again. Good to know about the new fork oil. I only saw the 5 weight oil at the dealer and he said he was out of the 7 weight. So I used BelRay 10 weight fork oil, which also feels good and firm for me.
Over years of oil passing thru dampening orfices, slightly enlarging from the friction created from the oil, using 10 weight fork oil became my choice a few yrs. back. Definitely a noticable improvement to handling and overall ride.
 
OP
OP
aSTerix
Joined
Dec 18, 2014
Messages
691
Location
Oman
Bike
ST1100AY
using 10 weight fork... Definitely a noticable improvement to handling and overall ride.
Do you mind me asking what improvements you find with 10 W , is it a case of feeling tighter in the corner but at the expense of softness on bumpy surfaces



Sent from my iPhone using Tapatalk
 
Joined
May 30, 2007
Messages
1,387
Age
72
Location
Grand Junction, Colo.
Bike
92 ST1100
Do you mind me asking what improvements you find with 10 W , is it a case of feeling tighter in the corner but at the expense of softness on bumpy surfaces



Sent from my iPhone using Tapatalk
No softness......just better dampening, slightly slowing oil flow upon initial compressing. Since no adjustment up front, this IS the suspension adjustment to better match the rear so both are working closer to same rate. Bel-Ray was used in this case, even though Silcolene would of been my personnal choice had the 10w been conveniently available off dealer's shelf at time. Both good oils, just my personnal choice from a few past decades of moto-x:rolleyes:;).
 
OP
OP
aSTerix
Joined
Dec 18, 2014
Messages
691
Location
Oman
Bike
ST1100AY
I'm deeply regretting using the 5 W now, not sure about 10W but definitely 7.5W would be better


Sent from my iPhone using Tapatalk
 
Joined
Jun 3, 2006
Messages
3,514
Location
British Columbia
Bike
2021 RE Meteor 350
I'm back on the road now with rebuilt forks and correct fork oil level. Interestingly the Honda Performance Fork Oil 5W feels firm so the note in the label that it replaces SS7M is accurate !
So, what's gone wrong since this post of yours? Suspension too soft? You might consider my suggestion in post #4 of this thread, where you put heavier oil in the right fork and since it is the easier one to work with (no damping rod), it should be an easy R & R.
 
Joined
Mar 13, 2012
Messages
5,047
Location
soCal
Bike
'97 ST1100
STOC #
687
So, what's gone wrong since this post of yours? Suspension too soft? You might consider my suggestion in post #4 of this thread, where you put heavier oil in the right fork and since it is the easier one to work with (no damping rod), it should be an easy R & R.
oops, I think he meant to say left fork, that's the one without the damping rod.
 
Joined
Jun 3, 2006
Messages
3,514
Location
British Columbia
Bike
2021 RE Meteor 350
oops, I think he meant to say left fork, that's the one without the damping rod.
You can correct me again, if I'm wrong, but doesn't the ABS model, as we are talking about here, have the fork internals reversed from the non ABS?
 
Joined
Mar 13, 2012
Messages
5,047
Location
soCal
Bike
'97 ST1100
STOC #
687
You can correct me again, if I'm wrong, but doesn't the ABS model, as we are talking about here, have the fork internals reversed from the non ABS?
Sorry about that, I missed the fact that its the ABS model. I retract my statement, sorry if that caused any confusion.
 
OP
OP
aSTerix
Joined
Dec 18, 2014
Messages
691
Location
Oman
Bike
ST1100AY
So, what's gone wrong since this post of yours? Suspension too soft?
I finally managed to get the bike onto some fast twisty bends (there aren't too many over here) and the front end was anything but sure footed.
 
Joined
Jun 3, 2006
Messages
3,514
Location
British Columbia
Bike
2021 RE Meteor 350
I finally managed to get the bike onto some fast twisty bends (there aren't too many over here) and the front end was anything but sure footed.
There's a lot of reasons, other than fork oil viscosity, that could cause that problem. Too high or too low tire pressure, misaligned forks, improperly torqued or worn steering head bearings, improper torquing sequence on the front wheel, tire condition, etc. etc.

A little more detail, besides "anything but surefooted", might hold a clue, but if you are planning to replace the fluid, in the one fork at least, try that first.
 
OP
OP
aSTerix
Joined
Dec 18, 2014
Messages
691
Location
Oman
Bike
ST1100AY
A little more detail, besides "anything but surefooted"
Here is a more specific description !! : On anything other than a smooth surface it now runs wide on corners, if I hit a bump during the turn the front end chatters noticeably and there is a definite feel of loss of traction, both exaggerated the faster I take the corner. All adds up to a feeling that the front tyre isn't sitting with a nice stable contact patch during the turn
 
Joined
Sep 10, 2011
Messages
2,211
Location
West Michigan
Bike
'98 ST1100
STOC #
8470
Here is a more specific description !! : On anything other than a smooth surface it now runs wide on corners, if I hit a bump during the turn the front end chatters noticeably and there is a definite feel of loss of traction, both exaggerated the faster I take the corner. All adds up to a feeling that the front tyre isn't sitting with a nice stable contact patch during the turn
The problem is the 14 year old fork design. And RaceTech says the springs are too soft and compensated for by too much damping.
And the RaceTech spring rate calculator says the stock spring rate is perfect for a rider that weighs ZERO pounds. BTW, they recommend straight wound springs, not progressive rate springs. Progressives are too difficult to setup.

If you want the best out of your forks, install heavier springs and a RaceTech Gold Valve ( in the right fork ) and Emulator ( in the left fork). The Gold Valve replaces the OEM valve and the Emulator sits on top of the damper piston. The piston gets extra holes drilled in it, so the Emulator does the job instead ( basically). I'm happy with the results.

BTW, Sonic springs are a little cheaper than the RaceTech springs and you can save a few $$$ by buying the Gold Valve & Emulator kit off Amazon. The result is a "plush , but firm" ride.
 
Joined
Jul 24, 2011
Messages
1,026
Age
71
Location
Hereford, AZ
Bike
2020 Moto guzzi V85T
Boy there sounds like a lot of things going on here.

First of all the fork suspension on a stock ST1100 is very soft, almost to the point on a 15 year old bike where it does need some upgrades especially if you do any hard cornering. I am not an expert by any means but I have done several forks and much research in to this topic.

Fork oil

Airspace

Spring compression

Fork oil level and airspace are critical to the dampening process of the forks. Oil does not compress, air does. Too much oil and the ride will be hard; to little it will be mushy. In my opinion volume is the better method for measuring oil. The specifications give you no linear measurement of the air space so what is the standard to use?

Fork oil weight. The orifices’ that are in the working mechanisms of the forks are designed to have a certain viscosity of oil flow through them. I would highly doubt that the oil over 15 years would make a notable increase in orifice sizes. To heavy of oil and the dampening will be slowed to the point where the suspension is very stiff, and the rebound is slow.

The springs do a couple of things, they set the ride height of the bike (sag) and the provide rebound force to bring the bike back to ride height.

So looking at this thread you now have a chatter issue with the rebound. First thing to me it sounds like there is too much oil in the forks and not enough air space. This is assuming that the forks were disassembled and reassembled properly.

So a couple of things. Were the forks 100% disassembled and were the bushings checked for spec? Assuming they were in spec. Complete disassembly is also need for the correct oil volume. The next question would be are you using stock fork springs? This is critical because the aftermarket fork springs will affect the volume of oil to be replaced. When you did the assembly process and you started to add oil to each fork, did you pump or actuate the fork and damper by hand? This is critical because this is like bleed a system of air. You want all of the air out of the dampening rod and pumped through the orifice’s. After this step and the correct volume of oil is in each side the reassembly can be completed.

If you have the aftermarket springs you need to calculate a new volume of oil. Here is the process.
You must weigh the old and new springs and record their weight. I use a good food scale that measures in grams. Now with the weights established you need to calculate each springs volume in CC’s. Take the weight of each spring in grams and divide that number by 7.8 (density of steel in grams per cc). This gives you the volume of the spring in cc's. Now subtract the old and new for each side and this will give you the difference in volume of the springs. Look at the recommend amount of oil per side and add or subtract the difference in volume accordingly. On my ST1100 I needed to add oil when I went to the RaceTech springs.

This is where exercising the fork during the assembly process is critical. All the oil may not fit unless this step is done.

One other note, make sure that the anti-dive is functioning properly. If it is stuck the ride will be hard and will make the forks chatter.
 
Last edited:
Joined
Mar 13, 2012
Messages
5,047
Location
soCal
Bike
'97 ST1100
STOC #
687
The specifications give you no linear measurement of the air space so what is the standard to use?
The specifications are provided in the Honda service manual for oil level from top of tube, no spring, fork fully compressed.
 
Joined
Jul 24, 2011
Messages
1,026
Age
71
Location
Hereford, AZ
Bike
2020 Moto guzzi V85T
Yea I found that in my Clymers manual to, but it shows how to measure but I have not found what the distance value should be.

One additional note on this. The measurement distance is only good if using factory springs. In my case I used Racetech springs and their volume is different that stock. The volume of the Racetech is less than stock. Meaning that if I was to use the stock measurement I would have to much air space. Hence the reason for using a volume measure rather than a distance measure.
 
Last edited:
Joined
Mar 13, 2012
Messages
5,047
Location
soCal
Bike
'97 ST1100
STOC #
687
Yea I found that in my Clymers manual to, but it shows how to measure but I have not found what the distance value should be.

One additional note on this. The measurement distance is only good if using factory springs. In my case I used Racetech springs and their volume is different that stock. The volume of the Racetech is less than stock. Meaning that if I was to use the stock measurement I would have to much air space. Hence the reason for using a volume measure rather than a distance measure.
The numbers are in the Honda manual, and they're different for L or R, and ABS1, ABS2, non-ABS. Don't have it with me, I'm at work, but I think you don't really need the numbers anyway.

You're right about the displacement volume of springs being different, but the oil volume specification Honda provides is based upon using the stock springs, same as the height specification. Its just a different way to measure to get to the same result. I think the reason they specify both is if you don't have a graduated cylinder to measure the oil volume, you can use the fork tube as a graduated cylinder and they give you the measurement to know how much 'volume' of oil to put in. Some people prefer to use the height method because if you don't get every last cc of old oil out, then adding the specified volume of oil back into the tube could result in slightly overfilling it.

So if you change to a different spring the volume method isn't any better than the height method in that regard. The height will be different if you put in the Honda specified volume of oil, and insert a different spring.

But once you change the springs I doubt the air volume needs to be exactly the same as stock anyway, so trying to precisely replicate that seems unnecessary. And, different riders need different fork setups, so there's really no right/wrong setting to begin with. As long as you measure either height or volume with your given springs, you'll be able to replicate the desired setting next time around when you change the fork oil.
 
Joined
Jul 24, 2011
Messages
1,026
Age
71
Location
Hereford, AZ
Bike
2020 Moto guzzi V85T
dwalby. I don't need the measurements as you stated above. I am guessing here but I would suspect that the distance measure is more for if you are just changing fork oil, since it is unknown how much oil is actually left in the fork tube. But it also could be used for a complete tear down too.

I find it interesting that just on the forks there are so many variables that impact the final result. A simple thing as to much or to little oil has dramatic impact.
 
Joined
Dec 8, 2015
Messages
26
Location
Ireland
I have read all I can find on this subject, but have one question I hope someone can answer. Everyone says measure the oil level from the top down, with the fork compressed, with the spring removed. But on the right hand side of the 99 non abs model, the spring is attached to and sits over the plunger rod. Does this mean the spring should be left out, but the rod inserted for oil measurement purposes (in other words, absolutely everything should be in the tube except the spring)?
Many thanks for direction on this
 
Joined
Mar 13, 2012
Messages
5,047
Location
soCal
Bike
'97 ST1100
STOC #
687
I have read all I can find on this subject, but have one question I hope someone can answer. Everyone says measure the oil level from the top down, with the fork compressed, with the spring removed. But on the right hand side of the 99 non abs model, the spring is attached to and sits over the plunger rod. Does this mean the spring should be left out, but the rod inserted for oil measurement purposes (in other words, absolutely everything should be in the tube except the spring)?
Many thanks for direction on this
yes, the spring should be removed, the rod will remain in the tube.

I've always used the volume method over the years, and decided to try the level method on the last oil change. To get an accurate level reading, you have to pump the damper rod and upper fork tube a few times to circulate the new oil and displace any air before taking the measurement. When I did this, I kept seeing oil flow past the fork seal onto the upper tube. Others have reported the same thing happening to them. IMO, it was too much of a mess to use that method on the right fork (non-ABS) so I'm going back to the volume method again next time.

Maybe my technique wasn't right, I don't know, perhaps I should have kept the upper tube extended and just pump the damper rod, but its difficult to reach inside the tube so you'd need to attach an extender to the threads on the end of the rod. And you have to compress the top tube fully before taking the measurement anyway, so if oil flows past the seal when you do that you still end up with a cleanup job on the upper tube when you're done.

I thought the seal had somehow failed mid-job, but I put it all back together and cleaned it off and its never leaked since while on the bike.
 
Last edited:
Joined
Jun 3, 2006
Messages
3,514
Location
British Columbia
Bike
2021 RE Meteor 350
Maybe my technique wasn't right,
The oil only gets past the seal if you fully extend the fork tube during the pumping process. Just partial travel pumping should clear the air. In other words, don't pull the fork tube up as far as it will go to prevent oil coming past the seal.
 
Top Bottom