OEM or Aftermarket Fork Seal

[millinaway]

I just bought a very clean, low hour 94 YZ250 (still had original tires mounted with tread left) Anyway, it has a fork seal leak and the guy had a set of Leak Proof brand seals that he gave me with the bike. I usually use OEM parts when I can but I am curious what you recommend. I have rebuilt a few older conventional forks but not inverted forks, but I have been trolling through older post on this board ( I just found it a couple of days ago ) and got a service manual today and it seems doable. Should I go ahead and order bushings, Orings and dust seals before disassembly or wait to see if they or anything else need replacement. This forum is a great source of information and I appreciate your time, effort and experience.

 

[agitt73]

the seals he gave you will work fine you will want to replace the
bushings also very common on yamahas

 

[shockdoc]

Not to start an aurgument with agitt73 but I would not use the leakproof brand seals. I know they have been around a long time but have never really been happy with them. I would use OEM seals and bushings but thats just my opinion.


doc

 

[bscottr]

Originally posted by millinaway
Should I go ahead and order bushings, Orings and dust seals before disassembly or wait to see if they or anything else need replacement.

I can’t argue with Shockdoc’s experience on the Leakproofs. I’ve used them as well as stockers with no problems. But I do not see near the seals he does and I also may have been lucky. FWIW: I ordered stock seals last time.

As far as the bushings go, if the bike is indeed as low hour as it sounds you may want to inspect the bushing prior to ordering new ones. Dust seal replacement is a good idea.

Good Luck,
Scott

Doc: Everything going well with the dealership in Daytona? Haven’t heard any updates in a while.

 

[DEANSFASTWAY]

Those leakproof seals always seem real sticky even the teflon or moly coated ones. Youll see when you put it together and the front end stays down and is very unreactive . . Ive seen them actually melt (the rubber)on streetbikes and leave long streakmarks on the tubes .May be OK on a Goldwingor Electra Glide with air forks but not too good on a YZ . IMO That YZ is a good bike I have owned a few of them with different size motors 285/ 360cc With a stock motor we were retarding the ign timing a bit and running a bigger main jet like 390 (here in Jersey ) the bike didnt ping and pulled very strong with good pump premium .Good Luck

 

[millinaway]

Originally posted by DEANSFASTWAY
With a stock motor we were retarding the ign timing a bit and running a bigger main jet like 390 (here in Jersey ) the bike didnt ping and pulled very strong with good pump premium

Thanks for the input. I kinda had a gut feeling about the leakproofs. I think I will use stockers and keep these on the wall for an emergency.
Deanfastway, why retard the timing? Are they prone to detonation? I have not really had a chance to ride it yet just a couple of quick putts in the yard. Dark when I leave for work and dark when I get home. Thanks again...Kevin

 

[flynbryan]

millinaway, yes if memory serves correctly the 94' model did have a detonation problem. I think I remember the mags saying the only way they could get it to go away was a mandatory use of straight race gas. Anyone w/better memory is welcome to correct me. Although it was indeed a great bike. No doubt the privateer bike of choice for 94'. It was a rocket ship w/some motor mods.

 

[CRPilot]

I had a 94 YZ 250. I can assure you that you have two easy ways to cure the problem. Run race gas, or send the head to Erig Gorr. He does a simple mod the to squish area (or something to that effect) to allow the use of pump gas. I spend many, many hours trying to jet the detonation out and never had any luck. I chose to run race gas and was never had a problem again.

 

[millinaway]

I know this is getting off topic but, will 100 low lead aviation fuel work well for race fuel (if jetted properly)?