Fork seals

[Gdub]

I'm new to the site. Reading through the posts has been entertaining and immensely informative. I just picked up a 1990 Venture royale. The right fork is losing air through the seal so that is my winter project. After reading a lot of posts it seems like a good idea to change to progressive springs while I have it tore down. Are the springs on eBay OK or should I get them somewhere else. I will use OEM seals. The other question concerns fork boots. There are some tattered remains of what used to be fork boots on the bike but I don't know if they are original or not. I can't seem to find any pictures showing them on other bikes and I don't know if I need them or where to get them if I do. Any ideas would be greatly appreciated.

[cowpuc]

Hi Gdub and to VR!

 

I may be misreading your question and if I am I apologize. I am assuming that when your talking about replacing the seal you are either talking about the seal around the cap on top of the fork or the seal around the collar that the air travels thru to get into the fork and you are not talking about the fork seal located on the top of the lower leg = the one that the upper tube slides thru when you press down on the front end? Guess we should get that clarified first..

If the leakage is around the cap, its a fairly simple fix = lift the bike so the front end off the ground, remove the cap and replace the o-ring on the cap. The collar would be more involved as you will have to remove the entire front fork, slide it out of the lower triple tree and use the triple trees upper edge to knock the collar off to replace the seals.

If it's the actual fork seal (the one in the lower leg) that requires removing the lower leg from the upper tube, that kinda makes me .. The reason why is it seems like you would have had to have lost a lot of fork fluid long before you would ever actually lose air. The reason I say that is that the air pressure that is introduced into the fork is actually pressurizing against the oil inside of the top tube and it works by forcing down on that oil,, seems like the tube would almost have to be empty before it could leak air out of that seal - make sense or am I thinking crazy again:confused24:?

Concerning progressives, I have almost completed wearing out my fifth 1st Gen and have yet to own one that came to me not needing progressives. The OEM springs tend to sack very easily. The easiest way to determine whether yours need progressives is to run all the air out of your forks and see how much travel you have in them. If you can hold the front brake and bottom out the forks with no air in them you indeed need progressives. Sitting on its side stand your forks should show 3 1/4 to 4 inches of travel exposed above the bottom leg - I have had them with only an inch or so of travel exposed with sacked out springs. I also might add that, generally speaking, I end up having to replace seals on forks when I end up with sacked springs and I have a theory that the reason for this is because of the pressure put on the seals from oil not having any place left to go - whether thats true or not I dont know but I do know that its VERY common to have blown seals with sacked springs.

I have purchased sets thru Ebay and have been very happy with them - they seemed to do fine. There are some small items that need to be addressed when you do the swap (like pre-loading and changing the fork oil) but nothing major.

Concerning fork boots. I am an old dirtbiker and very familiar with fork gators and am thinking we are talking about the same thing. These would be covers that go over the tube/lower leg and keep dirt off the upper tubes and fork seal area? The normal arrangement on our bikes is lower leg, seal (with bushing below it, washer, seal, washer, snap ring and then dust cover right above seal (think I got that right - been a while).. They did not come from Yamaha with a Gator or Boot over that joint.. Perhaps someone had stuck boots on your bike in an attempt to help keep seals in it. Personally, I dont think boots are a bad idea if your gonna be running a lot of two tracks but,, experience has taught me that boots can retain moisture which can create pitting on the tubes in certain environments and the type of boot your using.. I have ran a LOT of off road with my Ventures and, other than having to occasionally clean out the fork seals with a piece of old 35mm film negative (or a similar piece of thin plastic) found no reason to lean toward putting gators on my scoot..

Now, all that said, if I were in your shoes and we are talking about replacing the actual fork seals - the ones located at the tops of the lower legs under the "boots". Assuming this is where your getting air from.. I would double, triple check the bushings under the seals very carefully for fit. It is not uncommon for those bushings to go out of spec - especially if they have been ran dry. Those little suckers can and have caused some strange issues (low speed wobbles, premature seal failure) because the upper tubes can actually move laterally inside the lower legs. Not a bad idea to check em as long as you have it apart.

Hopefully I didnt loose you back at the first sentence of this thesis and that it helps you somehow. Lets keep our that someone with much more knowledge and ability to communicate it comes along if I lost you:big-grin-emoticon:

[Prairiehammer]

They did not come from Yamaha with a Gator or Boot over that joint.. Perhaps someone had stuck boots on your bike in an attempt to help keep seals in it.

 

The Venture came with fork gaiters/boots from the factory starting in 1990. Part number 3JJ-23191-00-00 BOOT. Still available from Yamaha, however the price is around $80 EACH.

[Gdub]

You raise a interesting question cowpuc. The previous owner said the air leak was around the fork seal and that there was some oil on the upper fork past the dust seal. I noticed a little oil but not a lot. I just got the bike and then sprained my ankle, so I haven't ridden much but it seemed to handle fine. I guess I need to do a little investigating to see if the air leak is somewhere else. I will do the other checks for the springs.

Prairehammer, thanks for solving the the mystery of the fork boot/gaiters. Seems a little pricey for something that I'm not sure if I need. Is that price from a dealer or a preferred online source?

[cowpuc]

Indeed Gdub, I too would like to thank that @Prairiehammer for sharing that.. I have seen and been around numerous 1st Gens (have only owned MK1's though) and never ever ever have a noticed that!! Ya dab burned lop eared varmint Kev,, every time I get around you I end up learning something new - THANKS a gazillion brother!!

 

Gdub, being new to the bike - it is possible that the previous owner actually rode the forks completely out of oil. Maybe put a little dish soap in a spray bottle of water - put air in the forks and spray around the forks and see if its leaking there. Also check the other areas. DONT FORGET TO CHECK THE SHRADER VALVE = WHERE YOU PUT THE AIR IN AT (be pretty cool if all it was was that little valve needed snugging up:big-grin-emoticon:).

If you do find that the air is leaking from the fork seals it might not be a bad idea to double check the condition of your front brake pads. If he ran the old girls forks dry so the air is now able to get out those seals, my money is on you will also find ruined brake pads cause the flow of oil going down the forks always seem to find its way into the brake caliper.. Makes a real mess in there but totally cleanupable..

All the best in figuring it out, keep us posted on your its coming when ya got time! Also, Godspeed on the ankle healing process- that stuff is never fun!!

[syscrusher]

Here is a good thread to refer to for some wisdom in re-doing the fork slider oil seal if that is what you need to do.

 

http://www.venturerider.org/forum/showthread.php?81910-My-fork-seal-seems-unrepairable-Help!

 

On my 1993 that has the accordion gators it was obvious that the seal was the leaky part.

It would not hold air and had a lot of trouble holding oil. The air helped push the oil out but also escaped on it's own.

Puc is confused about the schrader valve, your 1990 doesn't have them. It has the CLASS system instead.

There will be an air hose connected to disk shaped air manifolds around the top of each fork just beneath the top triple tree.

There is a retaining ring in a channel under them. It's possible their seals leak or the hose or fittings leak, maybe.

If there is oil on the upper part of your chrome fork tube I would look at the slider oil seal.

Maybe soap it up around those and then pump the CLASS up to no more than 21 PSI in the front, if CLASS works?

 

I reworked the forks 4 times before getting smart and replacing fork bushings too.

I also put in a set of the pre 1990 dust seals above my oil seals. 1990 and later had the gators and not the dust seals. I use both. Suspenders and a belt approach.

There is a good photographic reference in the "Tech Library" for replacing fork seals without removing entire forks from triple trees, much easier.

Read my thread and then read the tech library account after.

[cowpuc]

These guys are like Angels on my shoulders, THANK YOU @syscrusher!!

 

Best be listening to them Angels Gdub!

[cimmer]

One more thought on this subject is that with Progressive springs installed, I have found no need to add air to the front forks as the bike handles great without the addition of air. I would recommend replacing the fork oil no matter what you do and maybe do this first. You should find out fairly quick when you drain out the old oil. If you dont get much out, then you have a leak, if not , replace it and see what happens. The Progressive springs will change the amount of oil that the forks need but the directions for the springs let you know how much you need for each one.

Rick F.

[cowpuc]

One more thought on this subject is that with Progressive springs installed, I have found no need to add air to the front forks as the bike handles great without the addition of air. I would recommend replacing the fork oil no matter what you do and maybe do this first. You should find out fairly quick when you drain out the old oil. If you dont get much out, then you have a leak, if not , replace it and see what happens. The Progressive springs will change the amount of oil that the forks need but the directions for the springs let you know how much you need for each one.

Rick F.

 

Another EXCELLENT point the @cimmer

 

I always use a height gauge (its a syringe with a long metal needle on it - very common for doing dirtbike forks - I won mine in a drawing, thinking its a Motion Pro or something but could EASILY be home made) to set my fork oil amounts. I also set up my progressives with 3/4" of pre-load with thick wall pvc. Run 12.5 weight Bel Ray Fork oil and have NEVER needed to run air afterward either - even for trail riding!!! Yep,, really really good point Cimmer!!

[Karaboo]

Hey Gdub, my 1990 was also missing the gaiters on the forks and I was not looking forward to the dis-assembly required to replace them (or the cost from Yamaha). I looked at making some out of leather or vinyl, trying to adapt some chrome shields and several other options. What I ended up with was designing and printing some shields out on a 3D printer. They don't look too bad, but the important thing is the protection from road debris. They are a 2 piece design that bolts together. If you do end up taking the forks apart, just use the dust seals from the 89 models. They have to be cheaper.

 

[Gdub]

I finally got a few minutes to look for the air leak. It is definitely coming from the fork seal. I pumped the class up to 21 pounds and sprayed some soapy water on the seal. Wow lots of bubbles. Thanks for all the suggestions and hints. The pictorial for rebuilding the forks is excellent and I will be referring to it often. karaboo, your fork shields look pretty sharp but since I will be rebuilding the forks I'll take your suggestion and just put in the dust shields. I will post some pictures when I get done although it may be a little while yet.