Progressive Fork Springs & Fork Oil

[scty_p]

Well, I bought a pair of Progressive fork springs and finally got around to getting them in tonight. Just like I do anything that is new to me, I check it all out in the manual and here. Lots of good info all over. I left the forks on my bike and just removed the caps. The bike is on the centre stand for all of this. First off, I removed the schrader valve from the air nipple. The caps weren't too bad to remove, although, I did give 'em a rap with the air gun to loosen them. From the info here, I knew to push back as the cap would be under spring pressure. Once the caps were off, I removed the drain plugs to let out the fork oil. While the forks were draining I removed the stock spring sets. It was at this time that the bike decided to sit on her nose for me and tested the performance of my heart amid a great gasp filled with an expletive or two. I wasn't ready or expecting that, but DUH, what was there to hold it up anymore? Not a big deal as the forks need to be compressed to do the oil fill. I left the forks to drain overnight. This worked well. Also, while the forks were draining, I adjusted the TRAC adjuster and confirmed that the DOT goes to the number and that 4 allows the most flow and 1 the least. I've seen differing posts around and wanted to confirm it for myself. On to the oil and or fluid... I thought about tranny fluid and the concensus seems to be that dexron/mercon would be the choice over type-f. I opted for the Bel-Ray Performance Fork Oil in a 10W grade over the tranny fluid. By the way, at $16.00 for the litre, this stuff is near liquid gold, but I had my mind made up at that point. So, I started to fill the first fork and stopped rather abruptly to put the jug-o-liquid-gold under the drain hole that had yet to have the plug put back in. So, ensuring that the copper washers were in tact and in good shape, the plugs were installed. Now after the oil-dri is spread all 'round... ...back to filling the forks with oil. I also went with the Progressive method of filling to a maximum of 5-1/2 inches from the top since I didn't have anything to accurately measure the fork oil. I used a couple of zip ties fashioned in a "T" trimmed to fit and measured out the 5-1/2 inces needed and just sat that in the hole to get me close. Once I had the oil close in both tubes, I gently lifted the nose of the fairing to extend the fork travel to "burp" the lower end of the forks. I did this several times until I could no longer hear the oil gurgling in the forks. The fork oil dropped quite a bit from doing this, so I again topped it up. I have to go by a new turkey baster tomorrow as I confiscated that for my tool box to even out the levels of fluid in the forks. I ended up with a measurement of 5-5/8 in both fork tubes using another zip tie as a dipstick. It got late and I didn't finish the reassmbly in time for a ride. It is definately much stiffer in the front end... I hope not too much. A ride will tell for sure. Over all, not a bad job to do.

[Roleketu]

I just did the front Progressive's also. I did the suggestion of drilling the caps and putting in 1/8 inch pipe plugs. The Progressive instructions specifically listed the GL1200 to use 15w fork oil. I went with a filling of 7 inches from the top figuring that with the plugs I can easily add oil if needed.

[PanMan75]

I just did mine as well and used ATF. I filled 5.5" from the top. It is a stiff ride but I am comparing to my blown oil seals and 27 yr old springs.....lol

[SIR tricky]

If I remember correctly the level for Progressives was 5.5" from the top (with the spring removed and the forks collapsed)

[Roleketu]

If I remember correctly the level for Progressives was 5.5" from the top (with the spring removed and the forks collapsed)

Here's the cut-n-paste from Progressive's instructions.

2. Use the recommended fork oil viscosity as noted in your owners
manual with the following exceptions: GL1100 20 weight,
GL1200/1500 15 weight required. See fine tuning for more information.
Fork oil level/volume should be checked according to the steps outlined
in your authorized shop manual. Measurement of your fork oil
by level is the preferred method. However, some manuals only specify
a volume measurement. Due to the design of a progressive wound
fork spring it will displace more oil thus requiring a maximum oil
level of 5.5" (140mm). Caution: This is not a recommendation,
it is only a precautionary statement. If your manual specifies an oil
level higher than 5.5" (140mm) set the oil level at 5.5" (140mm). (Oil level is the distance from the top of the
fork tube to the top of the oil with the fork completely collapsed and the fork spring removed
see figure 1.)


Because they're saying 5.5 is the maximum level, I went with 7 knowing with the pipe plugs installed in the fork caps I can add oil easier verses removing oil.