Fork Rebuild for 1982 Seca XJ750RJ

I removed one front fork today and proceded to disassemble its inner components. In the lower outer tube I see what I believe is the oil-lock valve assembly. Is this piece supposed to be able to be removed? I see it stuck in the bottom through the two holes that the anti-dive units were removed from. I want to clean the inner lower tube. It looks like there may be plastic or rubber gaskets on this assembly. I am worried if I keep it in there that the brake cleaner will damage it. Any ideas on how to get this assembly out?

 

You can carefully tap it out by using a suitable tool (allen wrench, pin punch, brass drift) through the dampener rod bolt hole at the bottom of the fork leg. The oil lock usually comes out along with the dampener rod since it's almost a press fit to the dampener rod, but not always. You might need to turn it in the bore a little to break it free first. Use an allen wrench, inserted into the holes in the oil lock where the anti-dive bolts up, and give it a gentle turn.

 

K-moe thank you for the information. I was able to get the oil-lock valve assembly removed from the lower outer fork tube. The next issue I have is I am missing the two washers on the bottom end of the damper rod. They are paper thin. One is slightly bent from the pictures I saw in the chat forum "how-to-do". Does anyone have any specs on these two washers (I.D., O.D., thickness)? I would like to see if McMaster-Carr carries them. I am thinking the PO lost them when he had the forks worked on or they were never installed.

 

they don't, i looked

 

McMaster will very likely have them, but I can't quote you any dimensions as my only set are inside the forks on my bike. I do know that the I.D. is just a bit larger then the smaller portion of the dampener rod, and the O.D. is the same as the narrow end of the conical ring that sets just below them. My guesstimate is that they are no more than .5mm thick, and very likely thinner than that.

If you can't find direct replacements you might be able to use spring steel shims, and carefully put a wave into two of them. Metric Shims
If you go that route be very careful, and order more shims than you need. Putting a wave into a thin spring steel shim can cause it to develop stress fractures and it will fall apart in your hand. I have had good luck by gently massaging them into shape between my index finger and thumb (but I've only done that for applications where the shim isn't being asked to flex all that often).

 

Here are some pictures of the washers on my 82 XJ750RJ









I have a photojournal of a completely disassembled Seca 750 fork here-
http://www.xjbikes.com/Forums/viewtopic/t=41895.html

I would suggest finding someone who has an extra pair of forks who can mail you the washers. If you use a non-standard wave washer, your two forks will react differently to bumps(since you've only disassembled one). The springs and taper spinder form a relief valve that allow oil to bipass the antidive valve when you hit a large bump.

 

Guys, Thanks again for the info. Special_edy great pics. I did look at a couple fastner manufacturers including McMaster-Carr again. The metric shim washers come in spring steel, 316 stainless and 18-8 stainless. Which material would you recommend? They also run thicknesses from 0.20mm up to 2.5mm. The wave washer I am still looking into. I need to take some measurements on the conical spacer and dampen rod again. Are these washers just performing dampening between the dampen rod and that conical shaped spacer and oil-lock assembly? This probably means the anti-dive system never worked on this bike.

Another question, Inside the bottom of the inner fork tube there seems to be a washer/sleeve that is inserted in a slot. Is this a plastic/teflon sleeve like on the top of the dampen rod and also on the the oil-lock assembly? I hope it is not plastic. Just cleaned the inner tube with brake cleaner last night. That could make a mess of plastic.

 

I was unable to remove the plastic piece you are talking about inside the inner fork tube, it seems to clip in with 4 little tabs perhaps.
The washers force the taper spindle against the oil lock as demonstrated in the two pictures above. The first picture shows the assembly as it normally sits. In the second picture, I have simulated what happens when the pressure from the fork oil exceeds the force of the spring washer.

If you were to hit a large bump while braking, the conical spacer(taper spindle) would compress the wave washer you are missing and allow oil to bypass the anti-dive valve.

 

I am installing new progressive springs with my fork rebuild. If anyone else has upgraded there springs like I am, do you have the spacer length requirements? The new springs were sent with a PVC spacer that you cut to size. I have also been told the oil volume will decrease do to the different size of the spring and the PVC spacer. Is the spacer placed on top of the spring by the cap or on the damper rod?

 

The spacer goes between cap and spring, the spacer that came with my " Progressive " progressive springs was too short didn't even touch the cap after a couple of trial and error i ended up with 85mm for it. Which i'm comfortable with and 295ml of oil. I only weigh about 70kg, ride solo and don't often carry much stuff, your results may vary.

Put 'static sag' into the google machine and you'll find some useful reading.

 

If there is anyone out there that is in the middle of a fork rebuild on an 1982 Seca 750 and has the time to take some I.D., O.D, and thickness measurements of the damper rod shim washer and wave washer that butt up against the conical spacer it would be appreciated. I did measure the smaller diameter of the damper rod. It was 15mm. The larger diameter of the damper rod is 18mm. The smaller end of the conical spacer is 21mm. closest I found off the shelf was 16mm I.D and 24mm O.D. ranging from 0.1mm to 1.5mm in thickness. I have a friend that has a machine shop and would try and make them for me if I can get him some specs. I pulled apart the second fork today it it did not have these two washers either. Guess the shop the PO used to rebuild these many many years ago never put them back in.