4 Year Reliability Progress Report

Well, after 4 years of beating the living heck out of this bike (like gashes a millimeter deep and an inch long all over the bottom of the bashplate), I FINALLY had something go wrong with it. The left front fork seal started leaking oil. I still rode the heck out of it for 60 miles of rough single track this last weekend, but then it went into the shop and got new seals and a new battery (which was still working, but sounded a little weak when it was cold).

This bike is stupid reliable.

How many miles on your bike?

No idea. Haven't looked at it for a long time!

I do 99% off road on nasty "helicopter" single track (where you'd need a helicopter to get the bike out if it broke down) so the mileage isn't quite what it would be for someone who rides gently on the street. Next time I ride I'll look at it...

Did you bleed the the forks on a regular basis?

My fork seals were the first thing to go at 5 years, 12K miles. I should mention I was riding MX tracks for 2 months on the hearty R2, just before the seals went. I was getting some pretty good air but still shorting doubles on a regular basis. Never bleed the forks once, so I put the blame on me.

Get ya a pair of these ....http://www.motocrossparts.co.nz/motocross-parts-accessories.php?piece=1495&img=3

What does bleeding the forks mean? I never knew that was something I had to do!

GusinCA wrote:

What does bleeding the forks mean? I never knew that was something I had to do!

Takes 10 seconds. Here >> Bleeding Forks

It's not essential to put it on a stand first.

Very good info to know! I've been riding for 34 years and I never knew this. Old dog, new tricks!

Now, if I have the bike simply sitting on the sidestand, and I get the bleeder valves, can I do this or will oil come out?

GusinCA wrote:

Very good info to know! I've been riding for 34 years and I never knew this. Old dog, new tricks!

Now, if I have the bike simply sitting on the sidestand, and I get the bleeder valves, can I do this or will oil come out?

Oil will NOT come out (bleeder valves or screws doesn't matter). Side stand is ok. Lift is better.

Wonder if you blew the seals d/t built up pressure. If so, your trusty R2 still has a perfect record. Blame the seals on yourself!

I have no idea, there's no nicks on the fork tube, the dealer said it's normal after 4 years, so now I will order these bleeders and ride forever!

GusinCA wrote:

I have no idea, there's no nicks on the fork tube, the dealer said it's normal after 4 years, so now I will order these bleeders and ride forever!

Gusin, just so we're clear. You do not NEED to buy bleeders. You can just partially back the screws out to let some air escape and then crank them right back down. 5 seconds per tube. You just hear a split second .... tssss.

The after market bleeders just eliminate the need to use a screwdriver. They do exactly the same thing.

I suspect what the dealer was telling you about "no nicks" on the fork tube was that he noticed the bleeder screws had never been turned because normal use will result in some scratching of the screw head and fork tube from using the screw driver.

Notice that's what he looked for.

Yes, I know the bleeders are for convenience, but I bought them anyway.

No, what the dealer meant was that the shiny bottom part of the fork had no scratches on it, so that's a good thing, since it only means replacing the seals.

I'll install the bleeders, and happily psssst away my troubles.

Man, you guys are doing great to get 4 and 5 years out of a set of fork seals, especially on an off road bike. When I got my YZ from the PO, it had been sitting in his garage for about 2 years, unridden. First few big landings and both seals blew. Just another reason to make sure you get out and ride!   

My fork seals only lasted a year.

I do ride in a lot of mud tho.

Some of my rides are the worst thing you can do to fork seals tho... some muddy trail then some open fire road so the mud dries on the tubes then more mud then more open road lol.

Do those polystuff fork socks work?

sophijo wrote:

Do those polystuff fork socks work?

The neoprene protectors like Seal Savers will keep dirt away from the dust seals.  I've had them on several bikes, and they seemed to work well.  They have to be removed regularly to be cleaned, otherwise they can just trap dirt and water beneath them.  Fortunately, I think the Seal Savers are now zippered for easy removal.  Used to be I'd have to pull the forks off to get them on and off.

Make sure front tire is off ground when opening bleeders.

f3joel wrote:

Make sure front tire is off ground when opening bleeders.

Why?

Releasing air pressure with the forks partially compressed will remove more air than when they are fully extended.
Unless this is the effect you are looking for, the forks will then feel softer because you have reduced the "air spring" effect due to the air trapped between the fork oil and the fork cap.

Air spring = Just as with air pressure within a basketball, compressing the trapped air in the fork has it acting like a spring.
This air spring effect adds to the spring pressure that resists compression and returns that energy stored from compression during fork rebound.

In other words, it reduces the fork spring rate a bit.

The industry standard is to release air pressure with forks extended.

YZEtc wrote:

Releasing air pressure with the forks partially compressed will remove more air than when they are fully extended.
Unless this is the effect you are looking for, the forks will then feel softer because you have reduced the "air spring" effect due to the air trapped between the fork oil and the fork cap.

Air spring = Just as with air pressure within a basketball, compressing the trapped air in the fork has it acting like a spring.
This air spring effect adds to the spring pressure that resists compression and returns that energy stored from compression during fork rebound.

In other words, it reduces the fork spring rate a bit.

The industry standard is to release air pressure with forks extended.

How does air "build up" in the first place?

The seals are made and installed so that increased pressure within the fork as it compresses forces the inner lip of the seal against the fork tube surfaces. When the suspension extends there can be a negative pressure event within the tube which can draw air in past the seals. This plus changes in temps, atmospheric pressure or heat from rapid an repeated suspension movement can all alter the pressure of the air in the suspension component. The reason to bleed the forks is to keep the suspension rates more consistent. Increased pressure will increase (stiffen) compression resistance and increase the rebound rate. negative pressure will soften the resistance to compression and decrease the rebound rate.

I have and had bikes that use air pressure in either or the shocks and forks and have never had a seal failure due to the air pressure inside. Age of seal, yes but once replaced the new seals functioned properly and gave good service.

By 3000 km I've already got a ding in the back of the left fork leg and had to replace seal and scraper on my work WR-R.

I've fitted full-length neoprene boots (same material as the wipers you can buy). There's no difference to the fork action I can detect. I'm off to work this Sunday for a couple of weeks, then a short break, then another month or so.

I'll post up the results after this if anyone is interested. I think 4 years out of USD seals is bloody amazing. One lump of dried mud was enough to wreck my 426 seals.

Full length boots! Did you builds em? Yup I'm interested in how things hold-up.
Regards
Dave

Are inverted forks causing an epidemic of blown fork seals? (OP and my good fortune not withstanding)

sophijo wrote:

Full length boots! Did you builds em? Yup I'm interested in how things hold-up.
Regards
Dave

No, mate. They are basically neoprene tubes that slide over the fork legs. I bought them off ebay from England. I'll order some more if they work ok. Scrub and sticks will rip the crap out of them. I also fitted the fork protector rings over the boots, which isn't really successful, but...

I heated the white lower leg protectors with a hair dryer to expand them a bit, so's the black protector rings weren't rubbed so hard. Time will tell