Fork Spring Mod

[salty_monk]

Well according to the calculations I'll be starting with 25 lbs/inch and 56 lbs/inch when compressed, the compressed rate could be closer to 50 lbs/inch as it was a bit hard to get an exact measurement of the spring compressed. All very interesting. Although as Dan mentioned it appears I cut the wrong end, I cut the tight wound end instead of the loose end, I read and read on this subject yet still cut the wrong end, does that make me dyslectic or just stupid?? Anyways I'm glad I'm doing this as it's helping to motivate me to get her up and running.

A ton of people have done it the way you did it (me included on a couple of bikes). It's not "wrong" I just wanted you to understand it so you could better figure out what to do.
What you have done is akin to adding additional preload (i.e. you have changed the "start" point but not the final spring rate). It's not precisely the same & I'd need a bunch of graphs to explain it properly (& you'd be bored to tears!)

I also cut off the tightly wound end on my 1100 fork springs as I didn't want a progressive spring but as explained earlier i basically cut those springs in half anyway. (Danger here is that I might find spring fatigue sets in very quickly if I'm unlucky (not many coils left to share the work) but I have seen plenty of bikes (incl my KLR) that use springs that are as short or shorter than 14").

To get the compressed spring length you get a very accurate spring wire dia & multiply it by the number of coils in the spring, no need to actually measure it. I would be very surprised if you have managed to get 56lb/in from a stock GS spring.

[Guest]

So when they say compressed length they mean as if there were no spaces between any of the coils at all? and when they are asking for the free length it is the length of the spring only, not with spacers, right? I appreciate all this, like I said it's all very interesting. Punching in 47 coils with a wire diameter of 0.155 and an outside diameter of 1.05 with a free length of 13 1/2 inches means I will have a compressed length of 7.29...so....24 lbs/inch spring rate with a pressure at compressed length of 150 lbs, think I wrote it down wrong the first time. I did the same calculation for a stock spring from a 79 850 (which I think is close to the 1000G) and came up with 18.87 lbs/inch and 137.75 lbs at compressed length. So it's an improvement for sure but not what Sonic or Progressive would be.

[salty_monk]

You got it... Progressive is 35lb moving to 50lb when the coils bind (to calculate that you just alter the number of active coils - will be a smaller number).

[Wizard]

Full Extension

At the end of the day, you still need to have about an Inch or so, of travel available, in the fork tubes, while Loaded & Riding.
If you hit a Dip in Road, while in a turn, at speed, (I've seen you ride!), the front wheel needs to Extend and stay on the road.
Don't make it too stiff or a rough road (Goat Trails) will beat ya up.
For Touring I've actually backed off on everything, easy rebound, soft springs (low air pressure).

[bwringer]

You should have about 2.5 to 3 inches of travel, actually.

Static sag should be set at 2/3 to 3/4 total travel. Total travel on a GS (and most streetbikes) is just over 4 inches. (dual-sports are a bit different -- V-Stroms have about 6 inches of travel, KLR650s about 10 inches.)

Therefore, 1 to 1.5 inches static sag is about right for a GS. when you're traveling down a level smooth road, that's where the suspension should sit.

[Guest]

Well the engine is still sitting waiting to go back in so it might be a bit before I post of the end results but I'm looking forward to it. I'm thinking I may not ride this bike the same as the 78 but then again....