Whats up with Yamaha's and leaking fork seals?

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#1
All Yamaha's that are in the papers for sale, say "fork seals redone. Every yamaha we've owned the fork seals always go. And just recently my friend got his whole forks redone and now a few months later, there pi$$ing out oil again.This is the third time on his 1999 YZ250.I not saying Yamaha are bad bikes>there excellent;) .I'm just wondering why this is.Have they fixed this problem on the newer bikes (00-01's)?
 

marcusgunby

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#2
Most modern large tube forks seem to leak more than the older ones.It must be down to trying to reduce friction associated with larger tubes.Seal maintenance is often overlooked.
 

JAJ

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#3
Had the dealer replace my first two, in side of 6 months, at $125 per side. Changed them my self...haven't blown one since.

The key is to pack the space between the dust seal and oil seal with as much grease (waterproof) as you can. After you change them of course.

JJ
 
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#4
The vast majority of times when my seals are leaking, they need only be cleaned, not replaced. There are various methods for doing the cleaning; I use a feeler gauge and contact cleaner.
 
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#5
Seems like an issue... Pokie's 6 hour YZF (250) has bad seals already... I'm due to look them over this weekend, hoping they just need a cleaning... we'll see.

$125 a side! Ouch. $70 seal driver and your set for life.
 

yzguy15

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#6
I hear ya. The seals on my dad's 01 250 crapped out after about 5 or 6 hours. And then right about the same time, the seals on my 97 crapped out. Talk about a double whammy. Good news is that they haven't leaked again yet after at least double the hours on the 01. (Knock On Wood)
 

JAJ

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#7
Film negatives and business card work, as we all know. But remember, if your fork have been leaking for awile you'll have differing oil levels. Catch it when it first happens, definately fix it with a negative or a business card.

Funny thing, I just took my fork apart last night. I was kind of a pain to clean all that grease out of the space between the dust seal and the oil seal but, DAMN if all that grease didnt stop all that grime from getting into my oil seals! ;)
 
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#8
I have had the same problems with my 2000 YZ 125. I rode on the stock seals for a year and a half and then my left front one blew out on me. Some of it can be contributed to how you secure your bike to your trailer. If you tighten the straps as tight as you can get them you put alot of pressure on the forks which will cause the seals to leak. I cut a board to fit between the tire and the fender to keep my forks from compressing when when I tightened the straps.
 
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#9
Thank mx770 I was about to scream till you added the critical part about the spacers to compress upon. Too many people have lost bikes off the sides of trailers trying no to damage seals.

Ok here is my slightly controversial fix for what I believe to be bad chroming on older Yamahas, can’t comment on newer ones, though my YZF has been fine (but it’s a 750 so I try not to get it near the dirt).
The chrome seems to polish to super shiny & the seals don’t seem to seal against this. I give them a slight hone with some mild sandpaper in a cross-hatch pattern. This apparently is common practise on hydraulic rams.

I wouldn’t really try this on new un-shined up chrome but it was worth a mention.

$70 seal inserter? You mean a $4 piece of PVC tube?