fork oil level with Race Tech Gold Valve

serge

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After 5 years of bike ownership, I finally decided to install RT cartridge emulator.
Now I am confused about the fork oil level - RT recommends 120 mm
The service manual recommends 104 mm

keeping in mind that the emulator displaces some oil, following RT instruction will result in substantially less oil in the forks ...
am I missing something here?
 

670cc

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It seems that if the emulator will displace some oil, that is possibly why you would want start with a lower oil level before installing the emulator. On final assembly when all the parts are installed, maybe it brings the operating oil
level back up toward where the stock level was.
 

serge

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Thank you for your quick replies!

"The oil level is set with the Emulator submerged in oil" per RT instructions
but indeed before the spring goes in.
So I would guess this 120 mm level is counted for displacement by RT springs which are thicker than stock?
I am planning to reuse stock springs, so shall I set the stock height?
I guess 15 mm oil level difference is not that big to fuss about ...

I ordered an emulator from E-bay and did not get it yet, so only reading instructions on the website

(oil level step 14 on this link)
 

670cc

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Perhaps RT is not trying to mimmic Honda’s stock oil level, but through testing they have arrived at their own ideal oil level. Like you say, 15mm difference is not much to fuss about.
 

serge

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Those rods are mighty hard ;)
 

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Wedders

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I fitted gold emulators with RT oil level and they work fine far, far better than standard.
I first had a problem I will try to explain. When adding the oil you should pump the fork, but if the emulator is in it displaces it to lie sideways so when you install the spring the fork won’t work. I used the measurement of the emulator I think was 25mm added to the 120mm =145. This is how I set the air gap then inserted the emulator which then makes the gap 120mm and proceeded from there.
I hope I have shed some light on the potential problem because you won’t find it until you have reinstalled the forks and they won’t work.
 

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I found that bending up some thin wire to hang from the top of the forks tube to the desired air gap level and pouring up to the bottom of the wire simplifies this. You can maintain a balance on both forks and ensure consistency. My bike took near a full liter for both forks on a dry install. As you are aware positioning the valve in squarely is the trick. I use a 4 pronged grabber.
 

serge

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I ended up just pouring 500 ml in each fork and not cutting the spacer since I am reusing the stock spring for now.
I did not get a chance to test it off-road but it is not leaking which is already a win since it was my first fork seal replacement and I did not use Honda seals ;)
I reused copper washers on the bottom bolts, and one was stuck in the fork and another one the bolt..
 

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Should be good. I had trouble releasing the magnet probe during insertion. The thicker fork fluid needed for the G Valves should be harder to get through the seals too. You can make preload adjustments in the valve without removing the forks. Just use your magnet....

Let us know how you like them!
 

dduelin

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Should be good. I had trouble releasing the magnet probe during insertion. The thicker fork fluid needed for the G Valves should be harder to get through the seals too. You can make preload adjustments in the valve without removing the forks. Just use your magnet....

Let us know how you like them!
Isn't the oil level measured without the spring installed? When I use a extendable magnetic probe to install emulators I slide the spring over the magnetic probe and slide spring into place with the tool inside the spring. The spring holds the emulator in place as I pull the magnetic tool out.
 

dduelin

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After 5 years of bike ownership, I finally decided to install RT cartridge emulator.
Now I am confused about the fork oil level - RT recommends 120 mm
The service manual recommends 104 mm

keeping in mind that the emulator displaces some oil, following RT instruction will result in substantially less oil in the forks ...
am I missing something here?
Use the Race Tech level. It is measured before you assemble the spring stack so the RT level is higher than stock recommendation. You are not missing anything.

The stock forks use a lower level ( more air space in the tube ) to make the last 1/3rd of travel softer and less harsh than the simple stock damping rods allow. The air space progressively adds resistance as the air inside is compressed and this increases the resistance to bottoming out while still providing the softest most controlled response to low speed compressions. The stock set up tries to provide a soft ride over small bumps that compress the forks a small amount over a set time while resisting being too soft over a sharp bump that compresses the fork a long way in a short time.

Because the RT Gold Valves are able to separate high speed compression from low speed compression, the oil level can be higher to eliminate progressively raising spring rate to compensate for large orifices in the damping rods necessary to prevent harshness from low speed compression.
 

BFair

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Good thinking on the magnet. Yep oil level without spring, compressed. You must have a long mag probe.
 

NWGABikeGuy

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Use the Race Tech level. It is measured before you assemble the spring stack so the RT level is higher than stock recommendation. You are not missing anything.

The stock forks use a lower level ( more air space in the tube ) to make the last 1/3rd of travel softer and less harsh than the simple stock damping rods allow. The air space progressively adds resistance as the air inside is compressed and this increases the resistance to bottoming out while still providing the softest most controlled response to low speed compressions. The stock set up tries to provide a soft ride over small bumps that compress the forks a small amount over a set time while resisting being too soft over a sharp bump that compresses the fork a long way in a short time.

Because the RT Gold Valves are able to separate high speed compression from low speed compression, the oil level can be higher to eliminate progressively raising spring rate to compensate for large orifices in the damping rods necessary to prevent harshness from low speed compression.
Great answer! This is exactly what the suspension guru explained to me when he demonstrated the process with cut-away fork, spring, valve, etc.
Also, just an observation: I have almost always gotten good advice from the manufacturer of mods when I have questions about DIY issues. Best by phone, but also by email. They are usually quite willing to help no matter where you sourced the part. It helps if you can give them the part numbers and other info so they know what you are dealing with and that you are dealing with their parts.
 

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I have now formulated a plan to soften my suspension and increase fork travel.
1. Take 2 turns of preload off the valve, that will leave me with 1 turn.
2. If that doesn’t work put in lighter oil.
If both don’t work buy a new bike.
BTW I have emailed Race Tech asking for advice. Can anyone else offer any.
 
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frog13

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Unfortunately not. I'll be on here in the future doing my forks.......I know not what I'm doing regarding such......bwahahaha
 

serge

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Use the Race Tech level. It is measured before you assemble the spring stack so the RT level is higher than stock recommendation. You are not missing anything.

The stock forks use a lower level ( more air space in the tube ) to make the last 1/3rd of travel softer and less harsh than the simple stock damping rods allow. The air space progressively adds resistance as the air inside is compressed and this increases the resistance to bottoming out while still providing the softest most controlled response to low speed compressions. The stock set up tries to provide a soft ride over small bumps that compress the forks a small amount over a set time while resisting being too soft over a sharp bump that compresses the fork a long way in a short time.

Because the RT Gold Valves are able to separate high speed compression from low speed compression, the oil level can be higher to eliminate progressively raising spring rate to compensate for large orifices in the damping rods necessary to prevent harshness from low speed compression.
..I am still confused.. RT gives 120 mm and stock 104 mm, measured from the top to oil level - So more air would be with RT setup, right? At least before installing the spring..

I am afraid I bent something while replacing the seals.. When I was putting valve on top of the rod on one side it did not look centered and after installing the forks back they seem too wide on the bottom.. There is a gap between spacer and a fork after installing the wheel..

D8A26A6B-C749-4C40-9C1C-1648A95942AD.jpeg
 

dduelin

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The
..I am still confused.. RT gives 120 mm and stock 104 mm, measured from the top to oil level - So more air would be with RT setup, right? At least before installing the spring..

I am afraid I bent something while replacing the seals.. When I was putting valve on top of the rod on one side it did not look centered and after installing the forks back they seem too wide on the bottom.. There is a gap between spacer and a fork after installing the wheel..

View attachment 44854
You are correct. I got the oil level backwards. It is measured from the top of the tube to the oil level so RT's level is lower. No matter, it just means the RT instructions are to be followed and the resistance to compression will be less in the bottom half to 66% of travel. RT knows what they are talking about.

The damping rod does not align the forks, they are aligned by the top bridge and lower clamp. If the fork tubes are straight and the clamps are straight the forks will align. Typically only a collision or crash will bend a fork tube or clamp. Did you follow the service manual procedure when reassembling the forks? Basically tighten the axle to torque spec. Leave the left side lower axle pinch bolt loose. Place the bike on it's wheels and bounce the forks up and down to align the axle in the fork sliders then tighten the axle pinch bolt. Is the axle fully torqued into the left fork slider? The outside of the axle should be flush with the fork leg. Maybe you mixed up the left side and right side wheel spacers.
 
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