Checking fork seals/fluid

[Guest]

How do you check the integrity of the fork seals, and also the fork fluid health/level? Doing maintenance to all oils, so I wanted to include this if needed. Thanks all!

[bwringer]

If the fork seals are bad, believe me, you'll know it. They're very messy.

Checking fork oil level/condition is about 99.9% as much work as just changing the fork oil.

So no one checks it -- they just change it. If you don't know or don't remember when your fork oil was changed last, it's time.

[mmattockx]

How do you check the integrity of the fork seals, and also the fork fluid health/level? Doing maintenance to all oils, so I wanted to include this if needed. Thanks all!

If your fork seals are shot then there will be oil all over the top of the fork lower. It makes a large, very noticeable mess as bwringer says.

There is no checking the fork oil, it just gets changed. You can do it without disassembling the fork tubes or pulling seals, but it works best if you pull the forks off the bike. Basically, there is a drain hole at the bottom of the fork leg. You drain the old oil, then use kerosene or similar seal friendly solvent to rinse out the old sludge then refill with the correct amount of fork oil.


Mark

[RichDesmond]

In the future, the easy way is to change the fork oil when you change the front tire, you're already halfway there.

[mikerophone]

I agree with RichDesmond, once the tire is off, the fork tubes are only a few more bolts away. There are some good threads about changing the fork fluid or adding progressive springs here and on BassCliff's website.

Both fork seals were leaking on both of my bikes and even though I had already purchased the new seals, I thought if try my hand at re-sealing them. I made a "tool" and what do you know, they stopped leaking, I'll change them when I add progressives next year.

Some people cut one by hand out of a butter or Cool Whip tub. I'm a printer so I used .015" styrene and my CNC cutter. Here's my sealing tool, if yours ever leak, try resealing before you replace:

[Anthony]

What color should the fork oil be, and is this a separate type of oil you buy, or do you use a universal oil of sorts? When I removed the drain screw by accident for a few seconds, it was black in color.

[78550GS]

What color should the fork oil be, and is this a separate type of oil you buy, or do you use a universal oil of sorts? When I removed the drain screw by accident for a few seconds, it was black in color.

It's not supposed to be BLACK!

You should be able to find fork oil at just about any stealership or online.

[storm 64]

"When I add progressives next year."

Progressive springs, well there okay. But SONIC SPRINGS are the way to go! The owner is a great guy that offers good advice. Plus he's one of us. GSR member Rich Desmond...

[mikerophone]

It's not supposed to be BLACK!

You should be able to find fork oil at just about any stealership or online.

Personally I use a mix of 10W or 15W and ATF.

"When I add progressives next year."

Progressive springs, well there okay. But SONIC SPRINGS are the way to go! The owner is a great guy that offers good advice. Plus he's one of us. GSR member Rich Desmond...

Noted! I had no idea, and I replied to his post... I feel honored I'll surely check them out when I'm ready, thanks for the tip!

[LoyalSons]

Not sure about the 750, but my '81 550 according to the service manual calls for a mixture of SAE 10W/30 motor oil and ATF at a 50 - 50 ratio mix.

[mrbill5491]

What color should the fork oil be, and is this a separate type of oil you buy, or do you use a universal oil of sorts? When I removed the drain screw by accident for a few seconds, it was black in color.

Plenty of brands of fork oil out there, I've used PJ1, BelRay and couple of others over the years, all good fork oils. You can find them readily at any dealer or on line. Also it depends on what weight you would like, anywhere from 5 to 30 weight fork oils. Just remember one brand A's 15 weight oil maybe different actual weight from brand B or C. As for the color of your fork oil, depends how long it has been in use in the forks. I've seen it black to a grey color. Most oils have a pretty light amber (some are blue some red) color to them when new, though over time and use it will turn darker. I also change my fork oil about every 2 years.

[mmattockx]

What color should the fork oil be, and is this a separate type of oil you buy, or do you use a universal oil of sorts? When I removed the drain screw by accident for a few seconds, it was black in color.

Some older fork oils were black due to suspended teflon type particles in them. Most fork oil is not black anymore so you might as well change it and know what you have.

Personally I use a mix of 10W or 15W and ATF.

Not sure about the 750, but my '81 550 according to the service manual calls for a mixture of SAE 10W/30 motor oil and ATF at a 50 - 50 ratio mix.

I would never use anything but actual fork oil in a fork. Fork oils are formulated with ingredients meant to work in that application, especially anti-foaming ingredients. The others are not. Certainly they will work to keep the seals wet and prevent corrosion of the fork internals but there is no way they will provide damping as well as purpose made fork oils.


Mark

[Steve]

I agree with RichDesmond, once the tire is off, the fork tubes are only a few more bolts away. There are some good threads about changing the fork fluid or adding progressive springs here and on BassCliff's website.

You may not realize it, but that is almost a slap in the face right there.

Rich Desmond offers some advice, then you say you are going to buy a product from his competitor.

Rich is the owner of Sonic Springs.

What color should the fork oil be, and is this a separate type of oil you buy, or do you use a universal oil of sorts? When I removed the drain screw by accident for a few seconds, it was black in color.

I have seen clear, blue and red fork oil. It is specifically labelled "Fork Oil".

"When I add progressives next year."

Progressive springs, well there okay. But SONIC SPRINGS are the way to go! The owner is a great guy that offers good advice. Plus he's one of us. GSR member Rich Desmond...

There is no doubt that Progressive (brand) Springs are better than stock, but the general concensus is that, since the air that is trapped in the forks is also a progressive-rate spring, straight-rate springs of the proper rate will provide better overall response in the forks. Sonic (brand) springs are available in several specific rates.

Not sure about the 750, but my '81 550 according to the service manual calls for a mixture of SAE 10W/30 motor oil and ATF at a 50 - 50 ratio mix.

And the manual for your '81 550 was written using then-current technology.

They were suggesting lighter-weight motor oil for the somewhat-proper viscosity, then adding the ATF for the anti-foaming qualities.
Nowadays, true "fork oil" is much more readily available than it was thirty years ago, and has all the qualities that you need for proper operation.

.

[tkent02]

While you are in there putting in the new seals, Sonic springs and the new fork oil, consider cartridge emulators. They are not as good as a modern fork but they do a lot to smooth out the ride on these ancient suspensions. Easy to install if you are in there anyway.

[mikerophone]

You may not realize it, but that is almost a slap in the face right there.

Rich Desmond offers some advice, then you say you are going to buy a product from his competitor.

Rich is the owner of Sonic Springs.

I'm not the OP, and didn't realize the RichDesmond was the owner of Sonic Springs. Now I do, as noted by the post 4 down from that. I simply agreed with his statement about having the wheel off. When storm 64 pointed it out to me I noted it and said I will check it out, which I did. They offer 3 spring rates for my bike and are only $80 a pair. I'd much rather support a GSR member than someone I have no info on other then that guys at the local bike shop telling me they were good.

Had it not been for this post I may never have heard or Sonic Springs...