Finding on 06+ fork seal leakage.

[techmc]

Ok guys, I have done some research on this and here is what I am finding. On my 06 YZ250, at 20 hrs on bike I noticed seal on rotor side leaking,cleaned with tearoff lens,contact cleaner and wiped down and retested. But still leaked, so off came the tire and on with new seals, MSR red tri-lips. Put them on and after about 2-3 hours guess what? This time both were leaking but rotor side more than right side. I pulled off the forks for a reseating of seals to make sure they were in flat. Both looked fine and were level per caliper depth. Put back on forks and still leaked some but not quite as much.

The next day I had a race and the left fork seal started leaking like a son of a gun, so the next day I took off the left fork and checked again and all cleaned and looked good. This time upon reinstallation instead of putting the recommended torque on the axle nut per manual, I put about 15ft/lbs and locktighted the nut. At the track the next practice session I checked, and NO Leakage! none whatsoever on either side!!!! I put 3-3.5 hrs on it that day and no leakage.

Heres what I'm finding on mine and my buddys 250F and 450F fork leakage!

1. The frnt wheel spacer/s must be a little shorter than it needs to be.

2. When torquing front wheel on 06+ models the torque is pulling inner forks in just enough to make a gap for oil to leak.

3. DO NOT Torque Front axle nut to 75ft/lbs,per manual, if you have contant leakage on forks.

4. 10-15ft/lbs of torque is sufficient to hold all in place on axle without pulling on inner forks.

5. If you dont use blue locktight on axle threads, thread a short 10mm bolt into end of axle, that will hold nut on if it decides to back off.

I HAVE done this for over 4 months now with not a oil leak whatsoever!

?

Techmc

[CRF250dude26]

I was experiencing constant seal leakage with moose racing seals on my 250F. After about 3 rides they started leaking so I cleaned them and it stopped for a while, but now its leaking again, I will clean them again and torque it to 15 ft/lbs and see if it stops leaking.

[Deviousfred]

Good write up man!

[qwert321]

you know that the fork on the other side of the nut you are torqueing is suppose to float on axle until you tighten the axles bolts .there should be no pressure pulling in on your forks.

[techmc]

qwere321, yea its supposed to be floating, and mine did float then torqued down the pinch bolts to the axle, then torqued to 75ft/lbs per book, but somewhere along the torque of the axle nut, it is pushing my left fork in and/or pulling my right one also. How do you get 75lb/ft of torque on a axle nut without tightening the pinch bolts first. The axle will just spin untill it is pinched down 1ST! In doing this (tightening pinch bolts) you tend to push lft leg in and rht one in also. Step 6 on page 5-6 in manual states to Install axle nut to 75 ft-lbs then step 7 tighten axle holder to 17lbs. It says nothing about using a special tool to hold inner part of axle, to keep from spinning, so I think many people, and me; also have to tighten pinch bolts to hold axle while torquing. In doing so this pushes/pulls inner forks. With only SLIGHT torque on nut, this lets pinch bolts hold axle WITHOUT affecting fork placement. If I'm missing something here let me know ? But without a special axle tool, to hold axle while tightening axle, the pinch bolts have to be tightened 1ST to keep axle from spinning.....?

Techmc

[mxjosh]

Wow, I have been doing the front wheel wrong for 5 yrs. I leave everything loose then hold front brake and compress and decompress forks 3-4 times. Then I tighten the axle pinch bolts. After that I tighten the axle nut til it stops tightening easily. Then thats it. Its never come off or loosened on its own. No leaking issues either.

[RCannon]

The idea about side loading on the fork makes sense. I have used Forslyk on my fork legs from day one and have had no seal issues. It is somethign to keep in mind, for sure.

We all hate the "stiction" that comes from tight seals, but leaks suck as well.

[Pincushion]

I also used the pinch bolts to hold the axle while tightening the axle nut to 75ft/lbs. No problems in almost 2 years of ownership.

I had my forks done at about 25hrs and they reused the stock seals and I'm still using them. Got about 65hrs of hard use on them and no problems.

I dont think this is a design issue or we'd all be experiencing it.

[Reesknight]

Can you not tighten the pinch bolts, torque the axle nut, then loosen the pinch bolts and retighten them?

[DLHamblin]

qwere321, yea its supposed to be floating, and mine did float then torqued down the pinch bolts to the axle, then torqued to 75ft/lbs per book, but somewhere along the torque of the axle nut, it is pushing my left fork in and/or pulling my right one also. How do you get 75lb/ft of torque on a axle nut without tightening the pinch bolts first. The axle will just spin untill it is pinched down 1ST! In doing this (tightening pinch bolts) you tend to push lft leg in and rht one in also. Step 6 on page 5-6 in manual states to Install axle nut to 75 ft-lbs then step 7 tighten axle holder to 17lbs. It says nothing about using a special tool to hold inner part of axle, to keep from spinning, so I think many people, and me; also have to tighten pinch bolts to hold axle while torquing. In doing so this pushes/pulls inner forks. With only SLIGHT torque on nut, this lets pinch bolts hold axle WITHOUT affecting fork placement. If I'm missing something here let me know ? But without a special axle tool, to hold axle while tightening axle, the pinch bolts have to be tightened 1ST to keep axle from spinning.....?

Techmc

I have one of the Motion Pro fork alignment tools. Use it to prevent the mis-alignment you are talking about. I always torque the wheel nut to 75 ft/lbs. Haven't had any leakage from seals. Its a simple but effective way to make sure the lower tubes are alinged to the top with no side loading.

http://www.motionpro.com/motorcycle/partno/08-0412

[mxjosh]

Does it come with a spec sheet of where the tubes should be for each bike? Looks like a sweet tool.

[DLHamblin]

Does it come with a spec sheet of where the tubes should be for each bike? Looks like a sweet tool.

Yes, I guess I should explain; With the all the lower axle pinch bolts loose, I use one of those axle tools (a big hex driver) with a torque wrench to tighten the axle while I hold the nut stationary with another ratchet. Once its torqued down you loosen the bolts on the Motion Pro clamp and align it on the upper fork tubes. Tighten down the lock nuts. Then you place it on the lower legs to correctly line them up. The way the tool is shaped it sits squarely on the upper legs and also squarely on the smaller diameter lower legs. This ensures the lower legs are aligned with the upper tubes. While holding the tool I lightly snug up the pich bolts then finish by torquing them down.

Hope that makes sense; but if you have the tool you will see how it works quickly.

[mxjosh]

Got it. I read about 4 times but it finally clicked. I may look into that. Thx.

[techmc]

Yea Hamblin, GREAT.... with that tool there is no guess if the fork/s pull in 1-2mm, which no one can tell on tightening. Where would one get the "hex" driver to hold the right side of the axle before tightening. I haven't found anything right or strong enough to hold axle while tightening to 75lb/ft. (that's a lot of torque!" All my friends have to tighten pinch bolts instead of holding other side. This pulls fork/s in. Yamaha should put that in there special tools section! I haven't ever seen that fork alignment tool before and I have a friend that is a Motion Pro dealer??? I'll tell him to get me one! Thanks for the Great info. Next fork teardown i'll have that tool/s to do it right with.

Techmc

[RCannon]

This thread just got really good...stickie time. Thanks DL Hamblin for that fork tool.......another thing I have to have that can get lost in the corner of the garage!

[CRF250dude26]

Yea Hamblin, GREAT.... with that tool there is no guess if the fork/s pull in 1-2mm, which no one can tell on tightening. Where would one get the "hex" driver to hold the right side of the axle before tightening. I haven't found anything right or strong enough to hold axle while tightening to 75lb/ft. (that's a lot of torque!" All my friends have to tighten pinch bolts instead of holding other side. This pulls fork/s in. Yamaha should put that in there special tools section! I haven't ever seen that fork alignment tool before and I have a friend that is a Motion Pro dealer??? I'll tell him to get me one! Thanks for the Great info. Next fork teardown i'll have that tool/s to do it right with.

Techmc

I use a motion pro tool that fits in the allen wrench side of the axle, you put a wrench on the nut of the axle and use the tool to turn and tighten the axle. Since I have the tool to tighten the axle should I try less torque or are my seals blown?

[techmc]

If you can torque your axle nut down without the axle spinning or tighening both fork pinch bolts, you should be good to go! You wont blow your seal it'll just leak during riding. Here is a brand new tool that can verify both legs are straight at upper and lower area of inner fork!

http://www.motionpro.com/motorcycle/partno/08-0412

Thanks to DLHamblin:applause:

Techmc

[Reesknight]

Where would one get the "hex" driver to hold the right side of the axle before tightening. I haven't found anything right or strong enough to hold axle while tightening to 75lb/ft.

Techmc

http://www.motionpro.com/motorcycle/tools/t-6_hex_axle_tool

[mxjosh]

I haven't even got out my wallet yet and I already feel raped over that hex tool price! I can't see how that took more machining to manufacture than the fork tru?!

[dirtsquirt101]

I haven't even got out my wallet yet and I already feel raped over that hex tool price! I can't see how that took more machining to manufacture than the fork tru?!

Go here. http://buy1.snapon.com/catalog/tools.asp?tool=all&Group_ID=17898&store=snapon-store Look at the 2nd and 3rd tools down. Realize that the motion pro tool gives you 2 more sizes than them. Now all of a sudden you are getting a deal!