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How to figure fork oil level???
I am planning on draining my fork oil and replacing my springs with a set of Progressive's. Do I use the factory recommended amount of fork oil (323 cc's if I remember off the top of my head)? I know that the instructions from progressive say 5.5" from the top, but I am not removing my forks so I won't be able to get them level. How much oil do I need in each leg? Thanks!!!
1984 GL1200I
#1 02-09-2007, 02:47 PM,
Front Fork Oil Replacement

Release front fork air pressure.

On Aspencade, push the Suspension Selector (Front)
button. Push and hold the Air Pressure Decrease button
until air pressure is completely released.

NOTE: Drain and refill one fork at a time.

Place a drain pan below the fork and remove the drain screw. Work the suspension up and down to completely drain the fork.
Reinstall the drain plug.
Raise the front wheel off the ground by placing a block under the engine.
NOTE: Removing the fork spring will ease refilling the fork.

Remove the fork cap.

WARNING: The fork tube caps are under air and spring pressure. Be sure to release front fork Air pressure before dis assembly. Use care when
removing the caps to keep them from becoming projectiles.

Refill the fork with the specified amount of ATF

ATF Capacity (after draining): 323 cc (10.9 oz)

Progressive recommend 15 weight fork oil
The only stupid questions are the one's that are not asked.

#2 02-09-2007, 05:27 PM,
Is that 10.9 oz's with the Proressives installed? Why woudn't this number be standard for everyone that has changed over to using the Progressive springs in the front forks? Instead of having to go through the drain and fill and measure procedure. I'm trying to accomplish the change without having to remove the forks.

Forever The Optimist
1986 Blue/Blue Aspencade
Little Elm, Tx
"Go Lobo's"
#3 04-01-2007, 04:21 AM,
FTO, your question might best be answered by sending a note to Progressive. Spring wire diameter and numbers of coils can make a difference to oil volume in the fork legs.
Ed (Vic) Belanger - 1954-2015
Founder of

#4 04-01-2007, 05:26 AM,
This figure "ATF Capacity (after draining): 323 cc (10.9 oz)" is taken from the genuine Honda Manual."

Progressive says their springs displace more oil so that the preferred method is to measure from the top of the fork with the springs removed and the forks

If your not taking the forks off the bike I doubt that the slight angle that they are sitting at will make that much difference when taking the measurement.

Oil level is the distance from the top of the fork tube to the top of the oil with the fork completely collapsed and the spring removed.

I had my forks off this winter to replace the bushings so I did the measurement method.

When I installed the Progressives a couple of years ago I put the specified amount in as per the manual, it might have been a little too much, maybe thats why I found some oil in the air suspension controls when I inspected them this winter.

My friend did the same with his interstate (added the specified amount) when he installed his progressives.
The only stupid questions are the one's that are not asked.

#5 04-01-2007, 06:13 AM,
The method I used. Yes, I do tend to go a little over board at times.
Remove caps off both forks.
Measured the oil height on the left fork from the top to the oil level with the original springs in.
Now drained the left fork (pumped fork to get out as much as possible) and checked for quantity, mine was overfilled.
Drain plug back in; used new 15W oil and installed the the correct amount as per M/Spec.
Now rechecked level distance from top of fork tube to oil level, this is now the level you require.
Remove original springs, install progressives.
Used a 350 ml. beeker and poured the 15W oil in until I reached the level recorded when the correct amount was certified.
The difference between the 350 ml minus what is remaining in the beeker is now the new correct amount of fork oil.

The reason I went this long route; the orginal springs displace "X" amount of oil, hence mother honda decided the oil level needs to be at a certain height by using the amount of ml's she specifies.
So, when I installed the progressives I figured out how much oil they displace as compared to the original.

To make life easier, drill and tap a 1/8 NPT hole in the fork cap, now you do not have to remove the cap to change your fork oil.

Howard & Sharon Sims-GWRRA#259911
EX 1986 Aspencade
EX 2002 GL-1800

[Image: VisitedProvincesMap-copy.jpg][Image: VisitedStatesMap.jpg]
#6 04-01-2007, 01:31 PM,
I just put new seals in my 1500 with Progressive springs. The bit in the Progressive instructions really doesn't make a lot of sense. They say that their springs displace more oil than the OEM but that would vary whether you put your Progressives in with the tight wound end down or the other end down. After scratching my posterior I decided to refill the forks with the same amount of oil as Honda called out. Using the Honda callout the level in the fork tube was a good bit lower than 5.5". Since the level with 10.9oz. or so that Honda called for would be higher with the Progressives installed I couldn't see why I'd want to add even more for 5.5". After riding the bike yesterday it felt about right so I'll stay with the Honda volume of oil. BTW in my forks which are pretty much the same as the 1200, it took 14oz. of oil to get to 5.5" from the top of the tube with the springs out and the fork collapsed as specified by Progressive.
Current: GL1100 GL1500 Previous: GL1200SEI
#7 04-21-2007, 10:21 PM,
I don't see where it says the volume changes as to the placement of the springs in the Progressive leaflet.
It gives 5.5" as the maximum level and also states "this is only a precautionary statement" it goes on to state that if your manual gives a level of higher than 5.5" then set the level @5.5"

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The only stupid questions are the one's that are not asked.

#8 04-22-2007, 06:36 AM,
Ended up putting in the 11oz. that Honda called for, I'm not going to fiddle with a couple tenths of an ounce, and got a pretty harsh ride. Drained the forks and refilled with 10W and like that much better. BTW, I measured the oil that drained out of the forks to compare with what I put in and found that all but about 1/4oz. drained out. About a teaspoon difference. So I didn't worry about residual oil in the tubes when refilling. On my bike it was easy to refill the forks, I just removed the Schrader valve and squirted the oil in using a plastic condiment jug with a spout. Pushed a piece of tubing on the spout that would fit down into the fork cap valve hole and squeezed. I poured a measured amount of water into the jug first and marked the level on the outside with a Sharpie pen. If you want to drain the oil quickly, open the drain, tie or tape something to catch the oil and add a little air to the forks. Warming up the oil in the microwave sure helps to get it back in the forks, pours much more nicely.
Current: GL1100 GL1500 Previous: GL1200SEI
#9 04-26-2007, 11:29 PM,

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