im about to overhaul my forks so im thinking that now would be a good time to upgrade the fork springs. the options i might go with is either the HRC .95 springs or i may just go with racetech springs. my question is....what weight do you guys recommend? HRCs only come in the .95 rate but the racetechs go from .75 to 1.00. the is mainly street ridden, but I plan on doing the here and there trackday. I weigh 170lbs butt nekkid so i figure add 10 lbs for gear.
so far Im thinking racetech .95 since its the weight HRC recommends and I can get them for bout $75. Dunno how much the HRC ones are yet. Im guessing triple that since it "HRC".
find a set of used fork springs from a Honda VTR1000 Superhawk (they also have 41mm forks). I dont remember the rate, but when I calculated it before installing mine, they were perfect for my 180lbs weight.
The springs are a tad different length than the stock NSR springs, so you will need to cut some PVC pipe to make new spring spacers to match the stock springs/spacers.
If you are anywhere near a racetrack, you may even get these springs for free (racebike upgrade throw-aways). _________________ Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS
If you happen to find a spring that's correct for you but it's shorter than the stock spring then you're pretty much home and dry. Is mention previously, just make new spacers and you're good to go. The only thing is that if they're much shorter you need to make sure that they don't "coil bind" on full stroke.
If the springs are too long and you start cutting them you will actually strengthen the spring, so a 1k spring (for example) with a couple of coils cut off to make it fit, might actually jump up to a 1.2k spring. Sounds funny, but it's true. It's all about number of active coils. reduce the number of active coils and you increase the rate.
I've modified a lot of bikes here now for Supermotard, especially in the suspension department, and basically because Race-Tech aren't exactly just down the road we have done a lot of cutting and shutting with springs to come to the best rates.
I've done different things to my 500 springs (and valving) trying to get a supple ride through slow corners and a firm ride through the fast bits, and all on the stock, soggy springs. I've made them very slightly progressive (stock are constant), but this only works through the first very small part of the stroke. Under hard braking or fast cornering the progressive coils bind and we're on to a higher rate constant spring.
I'm gonna have a look at an NSR spring and see what can be done. I always cheated before and just fitted HRC springs.
Thing is though, if you're close to, or have easy access to a suspension shop products then you're probably just as well to buy the part. i don't because I'm a tight wad and I like to mess with things!
I would go to racetec they make springs for the NSR. They are only about $75.00 for a set of springs. They also offer different valving thats more Pricey. I just used heavier oil becase i'm cheap and It's my street bike. _________________
well guys, I got myself a set of racetech gold valves to throw in my forks. Although i m still working as to what spring weight to run.
Matt, would you recommend the HRC springs on the street? Im kinda leaning towards them since they're a direct replacment and they are "HRC". lol I just hope they arent too much for my novice arse.
thanks for the info guys1
JohnB,
the HRC stiffer springs are much more progressive than the stock set. They start at a lower rate and end at a higher rate. This makes it real nice, as your preload actually adusts the rate. The more preload, the higher range in the progression the forks sit. Basically, you can use these springs for lighter and heavier riders.
The VTR springs are almost identical rates as the HRC ones, if I remember right.
If you dont like the Gold Valves, I also have the shimstack info from the stock RS250 89-90 conventional forks like our NSR's use. You can use this shimstack info with your stock valves. With the Gold Valves, you are most likely still going to have to shuffle the shims to find the best performance. _________________ Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS
I've just fitted Paul's stock MC21 forks with heavier springs, and I also took the liberty of building a twin shim stack on the comp while they were apart.
Yet to find out what it feels like, but the plan is to give it a smooth/soft ride on the "fantastic" roads in town, but moving on to a stiffer stack when things get more hectic.
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