seca fork parts

i got this bike with the forks apart, the forks were held together by gravity, all the guts were in a bag
it seems to be a few parts went AWOL, anyone have any idea whats not there and where it goes ? are the pictures right so far?

 

Hi Polock,

You're missing the flat washer of the oil lock. There are two washers in the oil lock, a flat one and a wave washer. Both are very thin and made of pure unobtanium. I ended up fabbing one in a lathe from thin spring steel sheet stock.

As for the washer under the oil seal, Haynes is wrong. They show an O-ring, but these forks have that washer instead of the O-ring.

A lot of this was discussed on this thread: http://www.xjbikes.com/Forums/viewtopic ... art=0.html

Cheers,
Paul

 

Has anyone ever tried to make a replacement wave washer out of an old 1" tape measure blade, the tape measure blade I measured was very near the correct thickness.

 

i went back and read through those posts and have a problem with this from
Mr chacal

in the pictures from cturek and SQLGuy the wave washer and the flat washer seem to be the same O.D. so if assembled in that order their free to float from the OIL LOCK VALVE with PLASTIC PISTON RING to the THICK TAPERED WASHER, tapered/skinny end "up".
and not do anything
is there something here i missed?

 

mozark, after checking out the wave washer, i think a tape would be way too stiff
that washer is a wimpy little thing

 

I hear you on being wimpy, I had to straighten both of mine, you look at them cross eyed and they bend. I just wondered if after you got it cut out, no more material than is left, it would be that wimpy too?

 

One of the thin washers on each side is SUPPOSED to be "bent". They're wave washers. They're there to keep a small gap between the tapered washer and the top of the oil lock until sufficient pressure is applied to flatten them.

Polock: your picture shows the correct sequence of assembly (except for the missing washer, of course).

Cheers,
Paul

 

thanks SQL those forks were a major hurdle

 

SQL.....since Polock's picture doesn't really show the entire set of parts, and he's labeled it to show a missing washer going in one of two spots, can you explain what the correct sequence of installation really is?

TOP-TO-BOTTOM:

a) WAVE WASHER OR FLAT WASHER?
b) WAVE WASHER OR FLAT WASHER?
c) TAPERED WASHER, SKINNY END UP.
d) OIL LOCK UNIT WITH PISTON RING.

I think's it's just the placement of a vs. b that are in question, and perhaps it doesn't really matter?

If you observe the 900RK diagram, they show the order to be:

WAVE WASHER
FLAT WASHER
WAVE WASHER (again)
"TAPER SPINDLE" ---which is analogous to the 750 Seca "OIL LOCK UNIT"

Obviously---or, at least, according to the 750 Seca diagrams (which differ by year, by the way!)----the 750 Seca models used a single flat washer and a single wave washer, but the 900RK models used a single flat washer sandwiched by a pair of wave washers (and no, they aren't the same parts, the ID's of the 900RK parts are different).

 

i'am going to put them on
top
flat washer
wave washer
cone
piston ring thing
bottom
reason being the OD of the shoulder won't support the full width of the wave washer, thats what i figure the flat washer is for
now can anybody tell me if i can toss the anti-dive unit and just put a plate over the 2 big holes ?

 

I don't know what model of Seca your forks belong to. I have the Maxim 650 ('80, '81) Seca 750 ('81, '82) Yamaha service manual with the XJ750RH supplementary service manual in the back. The RH has a few more parts than the "conventional fork". Would scanned pages for the RH model fork disassembly/assembly help?

 

Beejer, that might help, but unfortunately, I can sum up in a nutshell what it says in there:

Per 750 Seca service manual, page 15.2:

3. Install damper rod in inner tube.

4. Install oil lock PLATE WASHER and VALVE SPRING, the
OIL LOCK VALVE, and the OIL LOCK PIECE on the damper rod.

5. ......also ALIGN THE MIDDLE HOLE IN THE OIL LOCK PIECE
with the LOWEST HOLE leading to the anti-dive unit.


Reading the above, you have to assume that the top-to-bottom order of parts is flat washer, wave washer, tapered waher, and then the oil lock unit with piston ring. We can only pray that Yamaha described the ORDER in which the parts are to be assembled onto the damper rod in the correct sequence.

Part of---actually, the majority of, and in reality, the ENTIRE problem with both the service manual and the parts diagrams (another, different version of which is included in the 750 Seca service supplement) is that the individual pieces are both:

a) talked about, and.....
b) are pictured, but.....
c) are never pictured with the descriptive words attached to them....which sort of leaves people to guess.

And via the exploded diagrams, the difference between the flat washer and the wave washer (a/k/a "valve spring".....hopefully!) cannot be determined, the two upper pieces are just vague, round circular things in the parts diagrams. The tapered washer is, hopefully, the "oil control valve" and the big bottom piece is most probably the "oil lock piece".

The parts diagram (depending on which one you look at) has a free-floating, large ring that is illustrated above the (hopefully) oil lock piece and the oil lock valve, and that ring is, I've always assumed, the white piston ring that is installed onto/around the oil lock "piece".............


I've usually found that between comparisons among the service manuals (both factory and aftermarket), parts diagrams (as many as possible, and from various sources), and having the actual parts in hand, that you can usually solve almost any assembly problem. These forks are one of the exceptional contradictions to that rule..........

 

Hi Len,

I did mine (from top to bottom): wave washer, flat washer, tapered washer (narrow side up), and then the bottom part of the oil lock valve (which stayed stuck in the bottoms of both of my fork legs).

I agree that it probably doesn't matter about the order of wave washer and flat washer, though.

Any luck on getting replacements for the washers?

Cheers,
Paul

 

Well I sure am glad this came up again since I just got my fork parts.
I had a shop rebuild them 10 years ago so I'm not even going to be sure they are correct when I disassemble.

 

Nothing yet, still at Ye Olde Machine Shop taking it's place in the everlasting queue.....

 

I have a different service manual than the one you quote chacal, probably because it's Canadian and all instructions are also in French (also why I was asking about the model and year of the Seca in question). It has an appendix which says it is a Supplementary Service Manual for the XJ750RH. At the end of that is "additional information" entitled, "XJ750RH Front Fork Disassembly/Reassembly", which contains several clear diagrams of the shock components.

Anyway, in the bottom bushing installation section it shows a diagram of the inner tube turned upside down with the compression cylinder pointing upwards from the bottom bushing. Over the compression cylinder is the flat washer, the wavy washer and then the collar (wide end on the top). So the wavy washer is trapped between the narrow end of the collar and the flat washer.

Above the top bushing is an L-section washer that points up towards the oil seal, the oil seal, a flat washer, the circlip and finally the dust cover.

 

Ah, then, Viva la Francais!

And yes, scans of the pages in question would be invaluable!!

 

Here's a link to the scanned pages from the Canadian manual, sans francais. I hope the diagrams make the part locations clearer for all.

http://tinyurl.com/q8z4by

Let me know if you have problems seeing these. After about 4 hours wrestling with resolutions, forum posting limitations, Picassa uploads, etc.,
all I can say is it shouldn't be this difficult to share information on-line. :?