Serious Fork Seal Problem!!!! Need Help!!!!

[94cr250]

I have a friend that has a 1999 YZ250 and he keeps blowing fork seals. He has had the bike for less than a year and has already had to have the fork seals replaced three and he blew the right fork seal from the third set on Sunday on a little puny jump that should not have blown them. Do any of you have any ideas on why he would keep blowing the seals like he does. Did Yamaha just put crappy forks on the YZ's that year.

Thanks

 

[Pit_Monkey]

there might be a piece of the chrome coating on the lower tube that has been lifted and is sharp. then whenever that part of the fort passes over the seal, it slices the seal.

 

[94cr250]

Thanks, I will tell him to check them for that. I think I remember seeing something in a magazine about a product that would prevent busted for seals, but I can't remember what they were called.

 

[David Trustrum]

On a fairly new bike I would not suspect it -but check the fork bushes. If there is excessive play in the fork assembly it will prematurely do the deals in. Also when fitting the new seals wrap some thin plastic tape over the sharp edges on the fork you have to get the seal over & use grease to get them over.

This is a little controversial but if the chrome is too polished I believe the seals tend not to seal so good & weep a little. Yamahas seem prone to this. I sand them giving them a v.light figure of 8 type motion (hone type pattern). I mean don’t go crazy or nothing. This apparently is std practise for hydraulic rams.

 

[dell30rb]

If he blows them over jumps it may be air pressure. Before you start riding take all the weight off the front wheel. Unscrew the air pressure realase screws ( they are on the fork cap) and then put them back in. After riding awhile normal action of the forks causes the air to expand in them and they build up pressure. So take the weight and repeat the procedure. Air should hiss out and the forks will be noticeably softer. Lots of built up pressure can cause not so good seals to blow

 

[ACS]

Could be a nick or two on the chrome or worn bushes but I stopped my 99 YZ125 from leaking by changing oil manafacturers. I had them serviced one time new seals and bushes (at considerable $$$$$) and next day they leaked in the trailer on the way to the races. Changed the leaking one myself at the track and used different brand oil and it was OK so next weekend I changed the oil in the other fork. End of problem. I have since done the oil in all the others and leaking forks a nearly (fingers crossed) a thing of the past.

The early 99's did have seal problems but Yamaha updated the seal, twice I think, and if you are using genuine Yamaha (or Honda 125 - they fit) seals they shouldn't be a problem.

 

[94cr250]

Thanks everybody, I will tell him to try that. I just found it kind of odd that he keeps blowing seals like every 2-3 months. I have just started riding again and kinda out of the loop on standards, but I would assume that fork seals are supposed to last longer than that.