Oil Level in Forks

[TownsendsFJR1300]

What is retaining your seals from being blown out?
While only 14 psi at rest the pressure will rise significantly as the fork is compressed.

What keeps the seal from blowing out the fork tube itself is the spring retainer(for an 04 FJR; https://www.babbittsonline.com/oemparts/a/yam/50044e19f8700209bc79150d/front-fork parts 9 and 32).

For my FZ6, retainer clip 11 and 31; https://www.babbittsonline.com/oemparts/a/yam/50045b95f8700209bc79415d/front-fork keeps them in.

Fork schrader valves are still used in new KLRs and have been used literally for decades. We used them often without springs for our Yamaha YZ 125's and 250's. Never had an issue with leakage and they were used on AMA sanctioned MX races in the late 70's.

**I have read (but have not confirmed on my own) that should you have a leaky fork seal, once the top of the lower fork leg is cleaned out, the retainer clip removed, 100PSI PLUS will blow the seals literally out of the fork (no disaassembly to speak of). Pop your new seal in!

I've had them in about two months now and love them. A whole different bike!

 

[Fred W]

Cool. I wonder if having them pressurized a little will help them reseat after you clean them inside with a sealmate?

 

[TownsendsFJR1300]

Cool. I wonder if having them pressurized a little will help them reseat after you clean them inside with a sealmate?

I would think, putting the Sealmate in the pressurized fork tube would help blow out (with fork oil) any crap in there.

The FZ has a rubber guard (part #20) attached to the lower fork tube that helps keep bugs (the main reason for seals to leak) from splattering on the upper tubes;

https://www.babbittsonline.com/oemparts/a/yam/50045b95f8700209bc79415d/front-fork

I try to keep the tubes as clean as possible (just changed the fork oil for the first time) and so far, no issues..

 

[Fred W]

If you have ever changed the seals on a set of forks in the past, there is a very good chance they were just dirty. A small (or large) guard really can't keep all the road spooge out, unless they are full on gaiters.

 

[rbentnail]

This is a duplicate post from here:

Some how, some way, I screwed up my front forks

. Dunno know how...

Using this procedure and the FSM I replaced the my fork oil. 92 mm from the top of the inner tube to the top of the oil, with no spring in it and with the inner tube fully compressed in the outer. I made sure as well as I could that the inner tube remained as fully extended as possible while attaching the inside rod and cap.

So now, on the center stand with the front wheel just off the ground the measurement to a convenient arbitrary point from the ground is 28 1/4", i.e., forks fully extended. I let the front end down and wait a few. The distance measurement from the ground becomes 25 1/4". I'm using 3" of fork travel just sitting on the center stand? WTF?

I used 10w oil from my local Honda dealer.

Any ideas?

 

[escapefjrtist]

Put a zip tie around the fork tube and measure again. Something's not right..

--G

 

[MCRIDER007]

Put a zip tie around the fork tube and measure again. Something's not right..
--G

What was the measurement before the fork oil change? If the sag has increased dramatically and the spacers were re-installed (correctly) then I would guess the lower part of the spring has slipped over the cartridge.

 

[Fred W]

+1 - There were several reports of that happening on 2nd gen bikes. I believe that there may be a small difference in diameter to the two ends of the springs, and the smaller end is supposed to go down and fit onto a small diameter flange on the top of the cartridge.

On 1st Gens there was a washer pressed onto that same flange to prevent the spring for slipping over it, but on 2nd Gens the spring seats right on it.

Here's a view of the top of the cartridge and the washer on a 1st Gen

 

[rbentnail]

True about the springs' having a larger and a smaller end. It's pictured specifically in the FSM with an arrow for UP. I'm pretty sure that's the way I installed them. Only one way to find out I guess.....

 

[rbentnail]

Put a zip tie around the fork tube and measure again. Something's not right..
--G

3". Measured with a tywrap on the inner fork tube. Bike on centerstand, had to drive up on 2 2x4's, no way the bike was going on the stand- too low. Then had to lift the front end manually to get a floor jack under the header pipes to raise the front end. Normally there's plenty of room so it's obvious the bike is sitting way way too low.

Jack under header pipes, front wheel raised off the floor. Tywrap installed on inner tube. Jack released, then raised again, 3".

Once again, I know something's not right, I just don't know what it is.

--------------------------------------------------------------------------------------------------------------------------------------------

Removed the forks again. Parts upon disassembly:

cap, nut, small inner rod, washer from top of spring, spring, long spacer. Spring properly orientated per FSM picture. All of these parts removed from tube before measuring oil level.

With the inner tube fully compressed down into the outer tube the oil level is about 93mm. I'm assuming the difference between the existing oil level and the 92 mm I filled it with is what's stuck on the parts I removed.

So, any ideas?

 

[boyitgobob]

Doesn't the spacer go on top of the washer that's sitting on top of the spring?

 

[rbentnail]

Doesn't the spacer go on top of the washer that's sitting on top of the spring?

Mine's a Gen2 so it may be different from what you have. Mine's a long tube-like spacer that slides down over the smalll inner-most tube that the rod goes in.

I think maybe I found the problem. I hope. The above stats are for the left leg, everything looks good there. The right leg oil level was at 115mm . WTF! How could I have screwed that up so badly? I'm off by 23 mm. Duh. Nearly an inch. I'm going back to counting lines on the rule instead of actually reading it. What a retard........

 

[rbentnail]

What would happen, hypothetically of course, if the washer that goes on top of the spring were thicker? Wouldn't that, in theory, stiffen up the front suspension a little by adding some squish, i.e., spring preload, to the spring?

Just thinking out loud since being it's Sunday chances of finding a couple of qts of fork oil are pretty slim.

 

[MCRIDER007]

Doesn't the spacer go on top of the washer that's sitting on top of the spring?

Mine's a Gen2 so it may be different from what you have. Mine's a long tube-like spacer that slides down over the smalll inner-most tube that the rod goes in.

I think maybe I found the problem. I hope. The above stats are for the left leg, everything looks good there. The right leg oil level was at 115mm . WTF! How could I have screwed that up so badly? I'm off by 23 mm. Duh. Nearly an inch. I'm going back to counting lines on the rule instead of actually reading it. What a retard........

Yes. the spacer slides over the threaded damper rod and rests on top of the washer that is sitting on the top of the spring.

I don't think your right leg oil level is causing excess sag since the oil level doesn't have any effect on sag during the first part of the fork's compressioon. The fork could be completely empty and the sag should be the same.

You can re-use fork oil, especially if it is new.

Back to my original question, are you sure the sag is different than it was before? Since you have the forks apart, how long is the spacer you are using?

 

[rbentnail]

Doesn't the spacer go on top of the washer that's sitting on top of the spring?

Yes. the spacer slides over the threaded damper rod and rests on top of the washer that is sitting on the top of the spring.

I don't think your right leg oil level is causing excess sag since the oil level doesn't have any effect on sag during the first part of the fork's compressioon. The fork could be completely empty and the sag should be the same.

You can re-use fork oil, especially if it is new.

Back to my original question, are you sure the sag is different than it was before? Since you have the forks apart, how long is the spacer you are using?

Now I'm having a real DuhHuh moment. I think the 6" long spacer was the last thing I took out. In fact, I'm really sure the spacer was the last thing I took out b/c I had to reach way down in and fish it out with a magnet. DuhHuh. When I assembled them I slid the spacer on before the washer instead of after it. DuhHuh. I even have pictures and still did it wrong. Have I mentioned DuhHuh?

And yes, doing what I did will definitely change the front end height. Trust me on this- the bike will be about 3" shorter in front.

Man oh man I sure feel like a world-class dumbass right now. ......

 

[MCRIDER007]

Now I'm having a real DuhHuh moment. I think the 6" long spacer was the last thing I took out. In fact, I'm really sure the spacer was the last thing I took out b/c I had to reach way down in and fish it out with a magnet. DuhHuh. When I assembled them I slid the spacer on before the washer instead of after it. DuhHuh. I even have pictures and still did it wrong. Have I mentioned DuhHuh?
And yes, doing what I did will definitely change the front end height. Trust me on this- the bike will be about 3" shorter in front.

Man oh man I sure feel like a world-class dumbass right now. ......

I did the same thing the first time I changed the fork springs, I dropped the spacer down the damper rod through the springs, installed the washer on top of the springs, and then installed the second spacer on top of the springs. Everything was OK until I put the second fork together and didn't have a spacer to complete the process. After searching for an hour for the missing spacer I finally realized there was only one place I hadn't looked. I was pretty relieved when I found it.

 

[rbentnail]

Well, I didn't do that. Each leg had an equal number of parts in it. Thanks for the chuckle, I sure needed it.

 

[bluesdog]

Bet you're glad it's not Friday...

 

[rbentnail]

You ain't kiddin'.....

 

[boyitgobob]

I was quick to spot that for two reasons. One, I'm about to service my 'new to me' forks and have been researching the spacer length because I think the PO may have set the preload length for two up. Two, I almost lost a radiator on a Speed Triple when the bike dropped and the wheel/fender just about kissed it. Truly a sinking feeling.