Fork Oil Level Wrong

Subject: Fork Oil Level Wrong Fri Sep 11, 2015 7:04 pm

Hi All,
Need to know what's wrong... Replaced the oil seals and dust seals on the front forks. When servicing one of the forks, I put in "approximately" 10 ounces of oil or so and measured the distance from the top of the fork to the oil.
Instead of the book-specified 3.8 inches, I'm only getting about 2.8 inches on the specified level, ie, like there is too much oil in there. This is after pumping the tube to get the air out.
So what do I do now??? Need help.

Latest update: Dumped oil out; double checked amount by using stolen measuring cup out of kitchen. Was an ounce or a little more over. Dumped oil back in; pumped fork. Now is closer but still shows being about a quarter inch too much. Am I picking nitts ??? Same held true on both fork tubes. Maybe I'll just go ahead and reassemble everything and live with it.

Latest: Latest Update: After rechecking levels with the kitchen measuring cup, it was apparent that I had put in a bit too much oil - - may two ounces to each fork. Anyway, the amount I put back in was about 10 ounces even. Pumped the tubes "slowly" as directed by the book and the final measurements were right around an eighth of an inch more than the book figure. So settled for that and proceeded to put them back together.

My spacers measured 2 and 3/8 inches so I made some 3 inch spacers out of some schedule 80 PVC and had a ball getting everything squeezed back in there (don't know how anyone manages a 3.5 inch spacer). Incidentally, with that schedule 80 spacer, I decided not to use the "spring seat". Think it's more for that sharp edged metal spacer anyway. Also, I used some 15 weight oil to see how much that changes things. Will let everyone know how it goes. Because of scheduling won't be able to get it all done til Monday or Tuesday.

Subject: Re: Fork Oil Level Wrong Fri Sep 11, 2015 10:14 pm

I am not an expert but I'd put it back together. The two sets I've seen redone were put back together with an extra ounce of oil and the owners both were happy with the results.

Subject: Re: Fork Oil Level Wrong Sat Sep 12, 2015 4:53 am

Here's my previous (lengthy ) post on my fork/shock experience. I didn't go with volume of oil when replacing but used the proper measurement: 97mm.

To dismantle the forks/shocks was very easy for me. I will try my best to explain:
1) place bike on double stand. Jack the front of bike off the ground and support it.
2) remove brake caliper, tire, fender. Shocks are now hanging freely. Let the caliper hang on its hoses. No need to remove the fairing.
3) use a 14mm socket to remove the bolts holding the shocks under the fairing.
4) hang onto the shock so it wont drop to the floor as you remove the bolts.
5) you will need a workbench with a vise to proceed
6) ALWAYS use a cloth or wood in your vise to protect your expensive shock. I repeat ALWAYS!!
7) clamp the body of the shock in the vise and loosen but dont remove the 8mm allen bolt on the bottom while its still pressurized.
8 ) with it still in the vise remove the dust cap and the seal retaining clip with a small screwdriver.
9) now clamp the chrome shaft of the shock in the vise. Use EXTRA CAUTION HERE AS NOT TO SCRATCH THE SHAFT WITH THE VISE. Clamp with the shock tipped upright as much as possible to prevent the oil from running all over your bench and floor.
10) use a 22mm socket to remove the top nut of the shock. This nut is under pressure from the spring inside but not a big deal. Just place your hand over the rachet to hold it all in place. It will only extend about two inches when released.
11) remove the shim tube, washer, spring and collar.Remove shock from vise to pour the oil into a container.
12) reclamp the body of the shock back in the vise
13) now dont panic here. You have to get something to stop the lower plunger on the inside of the shock from spinning to continue removing the 8mm allen bolt in step 7. I used my large rachet handle as it had a knurled handle. I think a wooden broom handle would work as well. Whatever works for you will need to be pushed hard while you finish removing the 8mm allen bolt. You can do it!
14) with the bolt removed now yank a few times to remove the main shaft out of the body, the seal will come with it.
15) slide the seal off the shaft along with the washer.
16) have a coffee, your half way there, now wipe all the parts clean to start the reassembly!
17) slide the guts of the shock back into the body thats clamped in the vise. Use the same procedure to stop the inside plunger from turning while you install the bottom 8mm bolt. Seems like once it starts to tighten you wont need to hold it from spinning.
18) now tap the top collar back into the body of the shock. I used a piece of 1 1/2 inch poly pipe split to slide over the shaft of the shock.
19) replace the large washer. Slide the new seal onto the shaft with the seals writing up and gently tap into place using a bluntnose punch and working around its circumference. I didn't have luck with the split poly pipe as it seemed to tip the seal on a possible damaging angle. Replace the snap ring. Install the new dust seal.
20) clamp the shock body upright, now push the shaft all the way down and pour in new oil (your choice of weight) till it measures 97mm from the top of the shaft to the top of the oil. Slide the shaft up and down to remove air bubbles before measuring!
21) replace the spring (the end with the tighter coils points up, open coils slides into the shaft first)
22) carefully place the shock on the floor and replace the washer and the shim tube (or the "new" extended ones as i did). Now with the cap nut in your palm push down and turn to start the nut. Took me a few tries to get this. Had to use a glove on my hand to help ease the pressure on my palm. Tighten the nut as much as possible by hand.
23) return the shock to the vise. Clamp the shaft tightly and tighten the cap nut with the 22mm socket.
24) now repeat the procedures on the second shock.
25) before you reinstall on the bike take note of the little groove about a 1/2 inch down on the shaft!? Not the groove for the bolt but the little one above it!! flush this little groove up with the top of the fork mounts. I had to use a flashlight to see that this groove was perfectly flush with the top of the fork underneath the fairing.
26) reinstall the shocks. Pushing the shock up gently will help you turn that top bolt.
27) reinstall everything else you removed
28) CHECK AND DOUBLE CHECK THAT YOU HAVE TIGHTENED EVERYTHING.
29) test ride
30) enjoy the fruits of your labor and a job well done.

I think i have covered everything. It may read complicated with all the steps but I found it an easy mod/repair. Good luck!

Subject: Re: Fork Oil Level Wrong Sat Sep 12, 2015 6:34 pm

hotwings, I believe I thanked you when you first posted this information. But just in case I didn't let me now say thank you for your very informative post. applause

Subject: Re: Fork Oil Level Wrong Sat Sep 12, 2015 7:38 pm

Yes... thanks are always in order for the instructions we have to follow. I, too, had to use gloves when getting that top cap back on. As a matter of fact, I left the socket on the cap to help push it down - - part of my trouble was that I was trying to catch the threads at the top of the fork tube... silly me... you have to really shove that cap on down into the tube where the threads actually start. Worked pretty good after that dawned on me.
Would have been installing them tomorrow but in the midst of everything my garage door opener failed so now I'll be headed to Sears to get a new one. If it ain't one thing, yadah, yadah, yadah... Thanks again for all the info.

Subject: Re: Fork Oil Level Wrong Sat Sep 12, 2015 9:31 pm

Hey Guys,
Just a little more info... That groove that gets lined up flush with the top of the fork mount... how does one go about assuring that?? I stuck the RH fork up in there and inserted the top (groove) bolt and then checked to see if I could feel that little groove above there at all. With that top bolt in and moving the tube up and down, I can't feel (or detect) that groove being flush at all (unless it is "just" inside the hole at the top. Doesn't that top bolt wind up centering in the bolt groove anyway ?? I guess I just don't understand that small "flush" groove and its meaning.

Secondly, don't the forks need to be left somewhat loose so that when the wheel and fender are installed and tightened down that that will be what squares everything up... and 'then' tighten the pinch bolts?? Confused... scratch

Subject: Re: Fork Oil Level Wrong Sun Sep 13, 2015 6:04 am

When I installed my Hyperpro spring I had no problem holding the forks to line up the grove that keeps the the tub in it's place. The lining up of the forks to the axle ,the bottom parts of the forks can rotate freely by hand to line things up.The bolt installed loosely in place,the forks will not slide up and down with the bolt in place.Line up the bolt with the axle the secure the fender in place.Good luck.Mike

Subject: Re: Fork Oil Level Wrong Sun Sep 13, 2015 6:39 am

I can't recall for sure but I believe the fork can still slide up and down ever so slightly with the bolt loosely installed. It's important to align that little groove because I think it may throw out your alignment or some other geometry if you don't. If you have been doing your daily yoga and head stretches it is possible to see the groove with a flashlight. Tighten the four top bolts completely before putting the fender/tire etc on. As Tinman says the bottom of the forks turn freely on their shafts, so don't worry about aligning the axle bolt at the beginning of the reinstall.

Subject: Re: Fork Oil Level Wrong Mon Sep 14, 2015 6:33 am

If i remember correctly the bolt hole is set in a way that the bolt can only fit when the tub lines up with the grove.If the tub grove is no lined up the bolt will not line up with the back of the tree mounting plate.The bottom bolt is a pinch bolt,it has to be remove to slide the fork tub out.

Subject: Re: Fork Oil Level Wrong Mon Sep 14, 2015 11:09 pm

I wound up pushing the tube up as far as I could get it (still couldn't see the little groove) with the top pinch bolt in place and then tightened the bottom pinch bolt and then the top bolt and torqued them both. Would still like to know the techy explanation for that little groove. Really don't see how you can change anything with that top pinch bolt tightened in its mounting groove. The rest of the operation pretty much fell back in place. Took the SWing out for a spin thru my yard/pasture and reparked it.

Checked the left fork again and there was a bit of oil there which I assumed was a bit of sloppy leftover. Anyway, wiped it dry, went for another another spin and it all checked out great. Had to pump the brake lever to get the pressure back up on the caliper but it firmed up fine too. Will take it out on the road as soon as possible to see how it does out there. Thanks once again for everyone's input when I needed the info.

Subject: Re: Fork Oil Level Wrong Tue Sep 15, 2015 6:03 am

The top bolt has to fit loosely in order to install the bottom pinch bolt in place. That keep the forks in place before tightening everything up.

Subject: Re: Fork Oil Level Wrong Wed Jun 22, 2022 2:20 pm

This topic lead me to add my findings with regard to the fork oil level. I recently did a front end overhaul and the fork oil level has left me thinking.

The Honda Service Manual says put in 302cm3 which equates to 302ml. i.e. 1:1. I put in 302ml but the level was about 45mm from the top of the fork. The manual says 97mm. If I reduced the level to 97mm I would have had to remove a large amount of oil.

I like to think that I followed the Manual exactly during this job but I left the level at 45mm. I'm pleased with the results of my labour but that discrepancy in the 'amount' versus the 'level' has left me thinking Suspect

Subject: Re: Fork Oil Level Wrong Wed Jun 22, 2022 6:28 pm

Just for clarity, the oil level is set with the forks compressed, and the springs out. Springs in will make a big difference to the apparent oil level. When refilling forks, it is also necessary to pump them many times to purge any air out from the area between the stanchion and lower leg; if you don't do that, the level will also be high (but will drop once the fork is in use).

Subject: Re: Fork Oil Level Wrong Thu Jun 23, 2022 7:39 am

I'm certain that I removed all the air. I had the identical amounts and levels in each fork which would suggest that I had followed the manual to the letter.

IAC the front end is now vastly improved after this job and I feel happier having put in the correct 'amount' of oil rather than the 'level' measurement. Smile

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