Rear shock rebuild..any special tools needed? /project thred

[Gotanubike]

Like I know if the springs are stock, I've had the bike for less than a year. Someone has been into it before because it had multi coloured zip ties holding the boots, oh and the dust seals are completely missing. I ordered some of those nifty sock shox.

I may just take the forks into my local shop with the seals and have them do it for me...

That racetech tutorial that Paul Theid did for the shock was great and followed that almost step by step. Only the tutorial he has for front suspension disassembly is for inverted forks.

[KDXGarage]

If you can't rebuild those forks, then you are in bad shape.

Those are very simple forks.

[Gotanubike]

Yeah well teach a man to fish, right.

Did the H series forks receive any upgrades compared to E series conventional forks? There is a half-arssed video guide on a seal replacement for 220 fork seals.



Also another more thorough guide for fork rebuild off an '86 Honda XL600R. Would you say the process is more less the same for all conventional forks?

[KDXGarage]

EDIT: Yes, the 1995+ forks are cartridge style instead of damper rod style.(edit over)

I watched the 1st one until he was putting the fork back on the bike. Yours is less complicated. I would offer the following add-on tips:

Loosen the upper clamp bolts, then loosen the fork caps. Do not remove the fork caps at that time, just loosen them. After the forks are off, then remove them. The lower clamp bolts being tight will hold the forks. While they are held by the lower bolts, the clamping force of the upper bolts will be gone and the fork caps can then be loosened. It is easier to do it then, rather than later by hand.

As you can see, he had trouble separating the tubes. Use a heat gu lightly or if you have the room for it, pour a couple of gallons of roaring, boiling water over the seal area, then quickly separate the tubes. It makes it a LOT easier. My concern on the heat gun is discoloration of painted or anodized surfaces.

Your first big problem (and anyone without the damper rod holding tool, such as the one sold by FRP Offroad), is that the damper rod will spin inside the fork when you try to remove the compression adjuster assembly. It is the same problem for cartridge forks and people who don't buy/make a cartridge holding tool.

<PREACH>...and try to use hand tools.</PREACH>

That second video is not really like your KDX fork. Just watch the 1st one, knowing it is not as hard as the cartridge forks he is working on.

[Gotanubike]

Cool...I won't have the seals until next week at the earliest so the more info I gather now the better off I'll be and less chance I'll have to muck something up

No air compressor but I have an electric 1/2" impact gun that might come in handy along the way. Would you not recommend any impact or chatter weapons?

[bufftester]

For removal of the hex bolt at the bottom of the fork the electric impact wrench is what I use. I have the FRP damper holder tool, but have never used it with an impact wrench. If all you're doing is changing the oil and dust seals you don't need to remove the damper assembly and can leave that big hex bolt alone Take out the snap-ring, drain the oil/remove the spring, then use the upper fork leg like a slide hammer to drive the dust/oil seal/washer out of the lower leg. When reinstalling everything put the new bushing on upper leg and insert into the lower leg as far as it will go, then slide the washer on. Then use the corner of a plastic sandwich bag over the top of the upper fork leg to slide the oil and dust seals on. That will help protect the inner lip of the seals from being damaged as it slides over the fork leg. Fully seat the seals, install the snap ring , spring, and add oil...1 down 1 to go then it's riding time! Whole process should only take about 30 minutes for both fork legs

[Gotanubike]

Awesome, do you happen to know the size of the top bolt on the upper leg so I know what I need to mooch from my brother, a 21mm or 22mm? I think 22mm but my 3/8ths set only goes to 19mm.

And that bolt comes off and spacer and spring are removed before anything else, right?

J, that compression adjuster hex fitment is larger than 10mm. My allan key set goes to 10mm and it's too small. It's more like 14mm or 15mm I think.

One more question, how much 10w oil per fork? I think the manual says 618ml +/- 4ml per fork. But on the next page it says to check the oil level with a special tool and should be 140 +/- 2mm from the top?

[KDXGarage]

I was thinking the damper rod slid down through the inner tube after the tubes were together, requiring the damper rod to be removed before the tubes were separated.

OK, it is 14mm on the bottom. My bad. I must have been focused on the 1986 - 1988 models.

The top caps are 22mm on the 1987, I think.

I am just not big on air tools on forks. There is a chance to spin the o-ring apart on forks that have those. That is why I had the PREACH around it.

[bufftester]

Jason, I don't disagree, with the FRP tool hand tools are all that are required. When I was playing with shim stacks and valving I made sure to have plenty of replacement o-rings on hand just in case.

That spacer is your preload adjustment, you can change it using a piece of 1" Sch40 PVC (search for more on that). Just remove the spacer, spring and spring seat (just basiclly a washer on top of the spring). If you don't want to remove the front end you can pump the oil out through the drain holes as in the manual, but I always just pulled the fork legs off and dumped the oil out the top, works fine either way.

When filling the forks back up don't go by the volume, go by oil level (measured with the top tube fully compressed and the spring installed). It's more accurate. And record the amount. Makes tuning your forks easier when you start playing with viscosity, level, preload, etc, etc.

And probably goes with out saying, but since they are apart it's the ideal time to install the proper springs for your riding weight if it hasn't been done. The KDX suspension is lopsided front to back. Springing it properly really improves the handling.

[KDXGarage]

I think it is measured with the springs out.

[Gotanubike]

In the manual it says to to add parts removed(spring, washer spacer) after the oil is added...The oil change procedure in the manual doesn't include removing the forks. If it were done that way, the outer tube would have to pushed upwards?

So with the forks off, 14cm from top of the inner tube with it fully compressed into the bottom outer tube...Does the inner tube meet any kind of resistance from from the damper spring when compressing? That would be hard to check the oil level if a spring was trying to push it back.

Also what kind of oil is recommended. Some say 10w is too stiff so they went with 5w and loved the results. Others say ATF (type F)? If so I may buy a jug of that and run it as gear oil too..

[bufftester]

I think it is measured with the springs out.

You are right, springs out, that's my old age and recall abilities in work lol. I used 7wt prior to my hybrid, it worked better for my fat arse in the KDX fork, my dad runs PJ1 which I think is like 2.5 or 3wt in his 93 (USD forks tho). The great thing about doing them your self is once you see how easy it is you can start playing around with them. Oil can be changed with the front end on the bike making tuning somewhat easier.

[KDXGarage]

I was not sure.

I think FRP recommended 7.5 weight.

Yeah, those drain screws really speed things up. Just don't use them for a "first change in a long time".

[Gotanubike]

Are you positive the cylinder unit/damper rod doesn't need to be removed before separating the tubes? In the manual it says to remove the compression valve from the bottom and the cylinder unit/damper rod out the top before it says anything about separating the tubes...

I have the top off and the spring out, dust seal clip and dust seal out and heating up the main seal but I can not for the life of me get the tubes to separate All I can hear the sound of solid metal contact and the seal has not budged a millimeter.

This is what I assume the special tool holds on to while loosening the cylinder unit? It's inside the inner tube while looking inside and placed just below the top of the outer tube...

[KDXGarage]

I was thinking the damper rod slid down through the inner tube after the tubes were together, requiring the damper rod to be removed before the tubes were separated...................

[Gotanubike]

Right then, so what size hex on the damper holder tool ? The FRP tool has 27mm and 30mm on either side. If I know the size, my brother mya have something at work.

[KDXGarage]

30mm

6 sided is good enough

[Gotanubike]

Great I should have no problem getting one made out of some steel rod with a T handle and a 30mm bolt head...would you say 18" is long enough?

[KDXGarage]

maybe 20 or so??

You just need room to get it on the top of the damper rod, then have room out of the fork to hold it.

[Gotanubike]

30mm from point to point and 27mm from flat to flat? That would be a 27mm bolt size..

Mr. Wibbens, in this thread says the E series needs a 29mm nut size and an H series would use 27mm

http://www.kdxrider.net/forums/viewtopi ... der#p64228