OK. I'v replaced lots of fork seals. Never an issue.

Gorilla replaced his seals then one started leaking. So he came over and we replaced it. Now 2 weeks later both are leaking.

In reassembling the front, the tubes slid in easily so the triples would appear to be aligned. We insured all was loose so the forks could self-align then tightened up the right fork floating spacer followed by the fork brace.

What would cause forks with seals replaced by 2 different people at 2 different times to start leaking within 2 weeks?

Hoping for ideas. Tubes looked clean with no scratches. Only thing I can now think of is the forks are bent a little which is causing the seals to leak.

What things can we look for today as we replace the seals again?
It has me stumped.

Oh, and he reports lots of oil consumption. Most common cause? Could it be valve stem seals? Piston rings? (We can do a compression test today)

It's crap quality seals or an imperfection in the tubes? (But I'm sure you have already thought of that)

EDIT: guess you can't rule out bad fork oil either??

On a totally unrelated subject, do you wanna go Scootin Shootin? I'm leaving for the National Forest soon!   

New fork oil not the cheap stuff.
OEM fork seals I put in. Not sure what he put in the first time.
We're going to look for any imperfection in the lower end of the tubes. Maybe bent. Maybe oval shape? 

Shooting where and when?

Above Greenwater, gunna take the scenic route up Green River Rd...today in a couple of hours??

Gorilla coming over now to work on those forks.

Was planning going to Champion tonight to test factory Ruger 25 round magazines in the 10-22 that came in yesterday (and other toys). Butler Creek mags are crap (jam every 4 rounds). Frustrated with the 10-22 because of that. Champion in Renton open until 9pm today.

If we get cone early, maybe SPAA range because it is close but they close at 4:30.

Will be doing .22's at the stadium on 35th Monday at 6:30.

OK..cool, I will give you more notice next time 

You're more than welcome to help diagnose the fork issue then go shooting 

(That is magazines came in yesterday - had the 10-22 and was frustrated with all the jams and determined Butler Creek magazines are crap. The lips are not designed the same as Ruger does it. So things do feed correcty.)

I see Gorilla has a 91 GS-E but don't see any reference to mileage on it.  If it has high mileage the fork seal problem could be due to worn bushings affecting the seal,  Check for bushing wear between tube and slider to see if its deflecting excessively due to wear.

On the same note, if he has high mileage on the engine his oil consumption could be normal for a GS with high mileage.  Based on my experience I wouldn't suspect a valve seal problem, never had a hint of one up to 80-90k miles on my 2 GSs.  If you shut down hot and let cool overnight like you do for a valve check see if the pockets in the head where the cam lobes dip in oil are still full, if they are the seals are OK.  Give the engine a hot compression check and then put a shot of oil in thru plug holes and check again.  A significant improvement in compression would indicate worn rings.

Under 9k miles.

There is a really bad oil stank right now. See the pix. Makes me think a bad bottle of fork oil. Seems BOTH seals are dissolving away. Once seal (right side of pix, the left one) they got with the bike( pair of new ones which they installed). We replaced the other one with an OEM 2 weeks ago. Now both are leaking.

My oil on the shelf doesn't stank. So we're not sure. he brought over fresh new from the store 15w fork oil. We plan to drain the forks. Put in fresh oil. Pump them. Drain them. Replace seals then put in new oil.




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added note: compression both sides was 155. With oil in the cylinders it went up to 180-185.

My 2c, check the fork runout, and replace the bushes. Then new seals and oil.

yeah, fork bushings could be a cause, but would have to be pretty bad to distort a brand new seal enough to leak.  i would double check that perhaps they wernt a bit over filled. could also rip em down again and check where the outer part of the seals sit and make sure the surface is very clean and free of pits scratchs or galling

I used to have this issue, and I think it was mainly because I was overfilling my forks with oil.   I have progressives, and I was filling to 99mm (stock).  Progressives require filling to 130mm from the top.  Also, one of my forks was worse than the other, and it had some minor looking pitting in the chrome plating.  I replaced that upper fork tube with a nicer one (from Adidasguy in fact), filled to 130mm, and they haven't leaked a bit for the last year and 2000 miles later.  I always used OEM seals, and I used 15w Maxima brand fork oil.  It does smell a little funky...

Info about mileage changes picture.  A 22 year old bike with less than 9k miles on it usually has some leaking seals from sitting around drying out too much of the time..  Your compression test makes rings looks good, time to check valve seals.  I buy bikes new or almost new and run them for many miles/year until they are used up at 80-100k miles or so, never had a problem with GS500 valve seals but that bike is a good candidate for bad valve seals.

On our first trip to the mountains we stopped about an hour  for dinner.  When we came out and started bikes son JP's GS1100E smoked like a chimney for a minute or two and then stopped and never smoked again that day.  A sure sign of bad valve seals when bike sits long enough for oil in the pockets in the head around the valves to drain down into the cylinders but not long enough for it to drain on down into the sump and thereby not smoke in the morning.  Or pull valve cover after shutdown and sitting all night to see if cam lobe oil pockets are full or drained thru the seals like suggested above.  Should notice this anyway every valve check.

You much more versed than me on this, but maybe the "flush" on the forks you could save a little money by using Automatic trans fluid.. I have done that on a measly 3 sets of seals with no recurrent issues.

I know some fill with trans fluid. You have probably thought of this, or maybe the maxima oil is the same as the trans oil with regard for cost.

I rebuilt the forsk on my new GSXR a few days back and couldnt believe how easy they were to do. Thankfully, the seals are holding. I would still hate to do everything again if I had to

Good luck with these forks you guys are working on

Everything is back together. We shall see if there are any further problems.
Impossible to put things back together wrong with bluesmudge and the world famous suzuki-stevo standing by. (Yes - quite a crowd at the Bike Cave today! Tomorrow Vashon ride if anyone wants to go. Meet at cave at 11am.)

Forks were checked for straightness. A-OK,
Flushed with new fork oil then same new fork oil put in to 130mm head space (progressive springs).

Pat, again...thanks for planting the Ruger 10/22 seed in the post earlier today, that's all the excuse I needed, a perfect "Scootin Shootin" gun!   
(how did things go @ the range?)

Took a shower. Sat down. Fell asleep. Was after 7 when I woke up so too late to load the car and get to the range.
I'll be doing the high school stadium range Monday at 6:30 (off of 35th, next to the golf course) if you happen to want to stop in. $4 fee and you could try out your new toy. Its open every Monday 6:30pm until everyone leaves. usually 9pm or so. 50 feet. Targets provided. 8 lanes.

Ruger 10/22.... man I really enjoyed mine - until our Govt decided they were too dangerous for the public to own and made them illegal, hit me with a gun buy back tax, then used the money they just took from me to buy the gun off me, under penalty of jail time.