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Fork oil capacity VFR750 RC36 1990.


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Hi guys I have few questions about fork oil change.

 

First, can I change the oil without removing anything from the inside? Drain the old one, and then put the new one, without removing springs etc? Can I screw something, cuz I never did fork job?

 

Second, I can't find how much ml of oil to put per one fork? I have manual for 1990 VFR750, but I can't find that info anywhere?

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You can, but how will you get all of the bits and grime out, and knwo fi you have any worn parts? 

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On 5/1/2022 at 2:50 PM, bmart said:

You can, but how will you get all of the bits and grime out, and knwo fi you have any worn parts? 

Ok thanks I wanted just to know if I can change it without pulling everything out. 

 

When it gets time for a full service, then someone who knows how to do it will do the job of course. I will just change the oil.

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Are you going to remove the forks from the triple clamps, or are you asking if there's a way to change the fork oil while still installed on the bike?

 

The latter can be done with some tricks, but if your oil is very old it can be sludgy in the bottom.  The "drain bolt" in the bottom is also the bolt that holds the bottom of the damper inside the fork assembly, so you are halfway to completely disassembling the fork at that point.  You already have the front wheel off and the bike on centerstand to get this far, its better to remove the fork and flush everything with degreaser and then fill with clean oil.  If you are suctioning out oil and replacing from the top cap and there's sludge at the bottom...well, no point to the oil change.

 

If you set out to disassemble the damper, thats when it becomes tedious and sensitive to torque values in reassembly.  But you can just flush that out really well and get by.

 

The only things left for "full service" are the bushings and seals, which are super duper easy to change. Easier than my mountain bike seals to be honest, which have to be pried out carefully 🙃

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3rd gens (90-93) and the very 1st 4th Gens acrually have a "proper" drain bolt on each leg

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2 minutes ago, Dutchy said:

3rd gens (90-93) and the very 1st 4th Gens acrually have a "proper" drain bolt on each leg

Weird...

 

🤔🙃🤷🏻‍♂️

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image.png.4aca34fa8182bdde847f23ad06cd7033.png

 

The 4th gens have the little nipple sticking out but no hole tapped like the 3rd gen pictured here

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On 5/1/2022 at 8:17 AM, Plavna said:

Hi guys I have few questions about fork oil change.

 

First, can I change the oil without removing anything from the inside? Drain the old one, and then put the new one, without removing springs etc? Can I screw something, cuz I never did fork job?

 

Second, I can't find how much ml of oil to put per one fork? I have manual for 1990 VFR750, but I can't find that info anywhere?

 

1. Yes, you can, but it is really not the best way to do this.  As others have mentioned already, there will be small particles of metal and other contaminants mixed in with the fork oil (how much depends on how long it has been since the last fork oil change), and the only way to get that "sludge" out is to fully disassemble the forks and clean them with a solvent like kerosene.

 

Early bikes do have the drain bolts mentioned above, but using them does not result in the removal of the sludge.  (Also note that fork oil drained in that way spurts surprisingly far horizontally--DAMHIK.)

 

The most effective "easy" way to change fork oil is to remove the wheel, brake calipers and the forks from the bike, open the top caps, remove the springs and dump the old fork oil out from the top.  You could then add some fresh oil shake it around and dump it out again, and each time you did this you would remove a bit more of the sludge.  Then put everything back together (except the springs--oil is measured without the springs and with the forks and damper rod fully compressed) and add new fork oil up to the OEM recommended level. 

 

2. Adding oil by volume is not as accurate as measuring the distance from the top of the oil to the top of the fork.  Once the levels are correct, pop the springs in and tighten the fork caps.  (The OEM oil level is 175mm on the Euro-spec 1990 VFR750FL.)

 

Ciao,

 

JZH

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JZH, 175mm is from the top of the upper tube to the fluid with the fork, compressed and without spring? 

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6 hours ago, JZH said:

 

1. Yes, you can, but it is really not the best way to do this.  As others have mentioned already, there will be small particles of metal and other contaminants mixed in with the fork oil (how much depends on how long it has been since the last fork oil change), and the only way to get that "sludge" out is to fully disassemble the forks and clean them with a solvent like kerosene.

 

Early bikes do have the drain bolts mentioned above, but using them does not result in the removal of the sludge.  (Also note that fork oil drained in that way spurts surprisingly far horizontally--DAMHIK.)

 

The most effective "easy" way to change fork oil is to remove the wheel, brake calipers and the forks from the bike, open the top caps, remove the springs and dump the old fork oil out from the top.  You could then add some fresh oil shake it around and dump it out again, and each time you did this you would remove a bit more of the sludge.  Then put everything back together (except the springs--oil is measured without the springs and with the forks and damper rod fully compressed) and add new fork oil up to the OEM recommended level. 

 

2. Adding oil by volume is not as accurate as measuring the distance from the top of the oil to the top of the fork.  Once the levels are correct, pop the springs in and tighten the fork caps.  (The OEM oil level is 175mm on the Euro-spec 1990 VFR750FL.)

 

Ciao,

 

JZH

Well then, thats is not a job for me. If I would do that this way I would pay someone to do it.

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On 5/7/2022 at 12:45 PM, bmart said:

JZH, 175mm is from the top of the upper tube to the fluid with the fork, compressed and without spring? 

 

Yes. 

 

For some unknown reason, US-spec bikes have slightly different levels specified.  (Maybe due to the initial conversion from ml to oz?)  The "air gap" does have a function in the way cartridge forks perform, but I'm very sceptical that a small difference in oil level would be noticeable.

 

Ciao,

 

JZH

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