82 GS650L fork cap

[exzachtly1]

Hello,
I have a 1982 GS650L, had it for a long time and decided to finally get around to upgrading the suspension. I ordered the Progressive fork spring kit for the front and started taking things apart tonight, following along with the guide on BikeCliff's site (http://members.dslextreme.com/users/storagecliff1/images/Install_Progressive_Fork_Springs.pdf). Unfortunately it seems like my bike, for whatever reason, does not have removable fork caps?



As you can see in the picture, I'm only able to remove the nipple for the air. It seems to be sealed up otherwise (and rusted to hell).

Do I have to disassemble the forks in order to put new springs in? Not sure how to proceed. Any help is appreciated!

 

[exzachtly1]

After some googling it looks like I have to press the inner plate down to reveal a removable clip. Like this:

https://faq.ninja250.org/wiki/How_do_I_remove_the_fork_caps/pistons?

soooo... upon doing this do I need to be concerned with replacing the clip or any other seals in there with new parts? Tips on getting the clip back in? Never done this before and I'd love not to mess it up

 

[Steve]

Yes, press down on the top disk, then pry the ring out. It is only a wire, there is not much force holding it there.

A deep socket that fits over the air valve and a 6" (or more) extension works great.

To install, just push the disk back down, slide the ring into the top of the fork tube, press it into its groove with a screwdriver.

.

 

[exzachtly1]

Steve! Glad to see you're still around. You helped me out a lot when I was getting started about 5 or 6 years ago. My account was deactivated due to inactivity so all my history is gone, but I believe you dropped off some idle mixture screws for my carbs in my mail box when I lived in Akron Cheers!

So I did get the caps out, the first fork I pulled was deceptive because it was rusted and quite stuck in there. Had to tap it in with a mallet and screwdriver, got the clip out and then turned it upside down to compress the spring and force the damn thing out. I guess i need to clean that thing up. The other fork was MUCH easier, lol. Just a little press with the socket as suggested and it went right down, clips were easy to remove with a pick.

Now for more noob questions haha. So I need to figure out spacers... the instructions for my bike are vague at best. No included spacer material so I need to figure out what diameter PVC to buy first. Next, because my caps are recessed... I'm not quite sure how to calculate the pre-load length for my spacer. It seems that they are suggesting a rule of thumb of having the spring/spacer combo be level with the top of the fork for a normal cap. Do I just start there, but add the length from top of fork to where the recessed cap sits? Or subtract? I'm quite confused by the instructions included with the springs. Also, the new springs are much shorter than my old ones, it seems like I will need quite a long spacer to start. Anyone have an "L" model that has done this before?

Finally - I did remove the air valve a few times from the cap that was stuck when I was fiddling. The rubber o-ring is a bit marred now. I'm not confident that it will seal properly... should I replace it? Is it going to be difficult to find a replacement or will any generic o-ring work? Harbor freight o-ring assortment maybe?

 

[Steve]

For a starting point, I would do the "flush with the fork" idea. Hold the assembled fork tube vertical, drop the spring in. Place the washer on top of the spring, then set your spacer material on top. Make sure the fork is fully extended, mark the spacer material at the top of the tube. When you push the spring in to put that top plate and circlip in, you should have enough preload.

To check if you have enough, you will have to have the bike pretty much fully assembled. With no weight on the forks (center stand or side stand should be good enough), measure from the top of the lower fork tube to the lower triple. Have a helper for this next step, you need to get on the bike and put all the weight on that you would have when riding. Have your helper measure from the lower tube to the lower triple. The difference between the two measurements should be about 15-20% of total fork travel. Most of our bikes have about 6 inches of travel, so 15-20% of that would be 1 to 1 1/4 inches. That measurement is your "sag". If the sag is more than that, add that much more to your spacers. If it's less, take that much away from the spacers.

Yeah, I'm still around. Different job keeps me closer to home, so if you need anything else, I'll have to ship it. :-\\\

.

 

[exzachtly1]

Thanks for the tips! That was quite the job haha. I got everything back together. The spacers, to the top, ended up being 2.25" but they're way too stiff at that length. Gonna have to take them off and trim down! One thing I'm running in to is that my rear shocks are so shot that they basically bottom out when I sit on the bike, making it really hard to tell if the weight distribution on the front forks is proper. I have new rear shocks coming on Tuesday - I think I will wait to put those on before I try calculating the pre-load again. What do you think?

Btw - I used the zip-tie method to measure, I think I saw it in one of the basscliff guides. When I sit on the bike I get about 0 travel unless I lean my weight forward more on the bars, then I get about 0.5"... I have a feeling I'm going to end up shaving about an inch off those spacers at least. I'll post the final measurements when I'm done for anyone else who might come across this thread.

 

[exzachtly1]

A couple of new things learned -

1) Something seems to be wrong with my center stand.... maybe. When I was putting the front wheel back on, the front was not lifted high enough at all by the center stand... I had to jack the bike up about 1.5" (I put a 2x4 under the stand) to get enough clearance to get the wheel in.
2) Due to point 1) I realized that I was measuring my sag wrong. This time I measured it from -actual- full extension, with a 1.25" spacer (reduced from 2.25"). It seemed about right.
3) ... so I took it out for a spin. Feels GREAT! Really improves the handling. Fantastic.
4) ... but my fork seals are leaking .... so I guess it's time to order those parts
5) I did wreck the o-ring on the air valve, it was seeping a bit of oil. Went to the hardware store, found a #5 o-ring and that seems to fit and fix the leak.
6) After my ride, I was able to tell how far the suspension traveled by the oil marks from the leaking seals. Seems to measure about 3.5" of total travel. Seems like a pretty sweet spot to me for active riding.

Conclusion:

- Should have done the fork seals while everything was apart. Oh well.
- For a 175 lb rider on a GS650L, right now it seems like a 1.25" spacer is about right.