Actually stiffer fork springs

And just for reference, here's the stock 35mm fork specs .....

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Easter Motorcycle Parts fork tube springs on order from J&P, part number 230-584. Replaces HD OEM fork spring, 45408-75.
Same specs as the Progressive Suspension part number, 11-1120 for $40 cheaper.

I'll report back with my results.
 
Following up on this.

Received the fork springs, as others have noted, they're a touch longer, but here's a photo for those curious.

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Installation needs a touch more muscle to get the cap wrestled down but nothing out of the ordinary for fork springs.

Bouncing the suspension in the garage there's an immediately noticeable difference. They're definitely
stiffer, but they also eliminate nearly all sag. Seriously, from fully extended with the wheel off the ground, to just standing the bike upright, there's probably 1-3mm of static sag, and with me on the bike there's probably 5-8mm or rider sag (I didn't actually measure since it was minuscule). Definitely not what I wanted to see there, but taking a ride proved that it was a worthwhile investment.

Overall the bike handles MUCH better. Far more composed in the corners, not such a willowy mess. The forks now better match the rear shocks and overall the ride has greatly improved. It's not overly harsh over bumps either, in my opinion. But, I am used to pretty taut suspension on my modern sport bikes. I wouldn't call it plush, but it's far from harsh. It's still plenty comfy.
And, the bike doesn't feel like it's going to bottom out as much, although it did still happen. But, then again, my testing methods are probably a bit aggressive :)

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For around $50 and 30 minutes of my time I'm quite pleased with the improvement. Could it be better? Absolutely, but it's going to take more money to achieve it and I'm satisfied to run it as is for the time being.
 
Did you add a bit more than the stock amount of oil? That really helps, the forks work better and dive less when braking. I just finished refurbing the forks on my '83. I Minton modded the damper rods, used 7 ounces of oil, and added 1" preload spacers to the stock springs. They're nice and firm now, even stiffer than my '78 with the MikesXS springs. The 1" spacers brought the spring height right up to the top of the tube with the forks fully extended, so installing the caps wasn't too difficult .....

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The guy above that suggested "air caps" has a point. That was a hot mod "back in the day".
Drill and tap the fork caps, not the adjustable ones, for pipe fittings (1/16 - 1/8 NPT) link the two sides together and have a single Shraeder valve where you can add or vent air.
The forks are basically a sealed chamber and the air space above the oil can be used as an adjustable spring. Air is a compressible media where as the oil is not. You can reduce the air space by filling with more oil which in effect will create a similar effect as long as you don't fill it so full it hydro locks.
You can drill and install a Shraeder valve directly in each individual cap but it's more problematic to adjust because the air volume is half as much. Linked is easier to keep them even.
It's a relatively inexpensive mod and something you could do quickly without having to wait for a kit to be delivered.
 
Remove cap, drop in spring, reinstall cap. Doesn't get much easier than that.

I agree, having adjustable air pressure does have an effect. However, it was not the correct solution for my needs. Adjusting the air pressure does not resolve the issue of the spring rate of the spring itself being too low to begin with.
 
5T, I added a touch of oil to compensate for oil lost with spring swap but I didn't adjust the level. I wanted to see how they worked as is first but I may just give that a try.
 
I understand very well how air shocks work. I ran Fox Float Evols on my race quad for years and those didn’t even have springs in them. They were true air shocks, they were also $1,300 a pair and far more sophisticated than 40 year old rudimentary forks. I ride my XS off-road, I ride it hard on the road, I jump it and wheelie it every chance I get. Upping the air pressure in these tiny little basic forks isn’t going to cut it. I put stiffer springs in it and got exactly the results I expected and wanted.
 
Madness had air caps, I removed them and went to the sportster springs, it also has the minton mods. I don't think it works quite as well as Resto with sporty springs and mikesXS cart emulators. But BOTH set ups are better than those flaccid stock springs.
 
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