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Discussion Starter · #1 ·
In reading the manual for my 1994 900 Sprint, it indicates that I must remove the fork to empty the oil (by turning the tubes upside down). Has anyone tried using a small pump with a long narrow hose to remove the oil? It seems like a lot less work as long as all the oil is removed.

Also, has anyone had experience with the HyperPro Progressive rate springs? I would like to firm up the front suspension without spending a fortune. My thought was to go with progressive springs (with the right rate for my weight, etc.) and some 15 wt. fork oil.

Thanks - now I'm going to bed - I've stayed up too late again!
 

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You will need to remove the forks, turn em upside down and pump them to remove all the old oil.
The inside of the forks arent just smooth tubing. You have all the oilways and valving down in there that controls the fundamental character of the forks.
When adjusting the compression or rebound on the bottom of the fork legs its actually altering the flow of the oil within these oilways.

Thats why trying to pump/syphon the oil with them in place cant get all of the old oil out.

I personally dont think the bike needs different springs. Try em with the 15wt oil first. See how they feel. If you still think you may need new springs after that its a simple task to whip the fork caps off and swap springs over.
Also, you can try this:
loosen the fork clamps (one side at a time) and push the tube upwards through the yokes by 10mm.
Measure it from the top face of the top yoke. Like I say, do one side clamp it off then do the other side.
This, together with 15wt oil, will transform the front end.

If you know someone who knows how to set suspension up get em to check your "static sag".....
If you cant find anybody who is good at set up youre just gonna have to come over and see me :p
 

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Darthandy: The trend over the last decade or so has been to move away from progressive springs back to straight weight. One reason is that static sag can't be properly set with progressives, another is that it's becoming widely recognized that the progressive springs currently in use just don't give the benefits they were supposed to. (The stock spring is a triple rate progressive.)

I am not an expert on springs, just giving you some background on why I chose to go with single-rate springs for the front-end swap I'm doing on my RS.

Wheeltrax: You've mentioned a number of adjustments that will make a difference, but none of them will do the same thing changing the springs would...

Cheers,
-Kit
 

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Discussion Starter · #4 ·
Thanks

Thanks for the info guys. Much appreciated.

By the way Wheeltrax, my particular Sprint doesn't have any adjustments for rebound, etc. but I can see what you mean about trying to scavenge it with a pump. Coming to see you may be an option, depending on where you are.

It looks like I have a fork removal to deal with in the meantime. I really do have to do something about that brake dive. It is very disconcerting, especially compared to my old RZ350 with its air forks.
 

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More than one way to skin a cat fella! :D

Get springs if youre willing to pay out. theyre not too expensive and, off the top of my head, about 90 pounds should about do it.

or.....

1. Replace your oil (15 or even 20wt. 20wt works well but takes time to warm up)
2. Use your existing springs but before replacing the fork cap place 3x 2mm washers (of the appropriate diameter) on top of each spring.
What this is doing is acting as 6mm of preload without having adjusters. Should bring your static sag into the right ball park.
3. Once your forks are ready with new oil and preload washers set them at 10mm up through the yokes.

I GUARANTEE that you will have a smile on your face after the first test ride. ;)

Ok, none of this is the same has having multi-adjustable forks and, yes, springs will make a difference, but the above mods will transform the front end of your sprint.
 

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Discussion Starter · #6 ·
Thanks yet again Wheeltrax. At least the preload is adjustable (sort of). Now if only the temperature can creep up a bit more so that my unheated garage can stop imitating a meat locker and allow me to do this work without losing a few digits. :eek:
 
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