two piece fork spring? Normal??

[brand new bike zealot]

First bike, first real dive into the land of engine maintenance, ect. ect... Anyway, decided to drain and replace the fork oil in my 78 550 and not bother redoing the seals or anything (don't seem to really leak) and as the cap unthreaded and shot up in the air along with the springs inside it turns out there are two progressively wound springs with a washer inbetween. I'm thinking this isn't stock as my clymers doesn't make any mention of it. Anyone heard of this before? Is the washer supposed to slow down the speed the oil travels between or something? Did someone bojang the wrong springs in?

Also, all I did was drain the oil (black black black), pour through some solvent, let dry, and fill with the factory spec'ed volume of belray 15w. Was this a bad idea? I didn't do any of the compress the fork and measure the height stuff. The forks seem to work just fine, reacting like a slightly worn car shock on a parking lot bounce test.

Any thoughts?

[Carter Turk]

I think the springs you have are from Works Performance. Supposedly a good fork spring, better than stock anyway and as good or better than Progressive springs.

You might check there website to see any info on your springs.

As far as the solvent, I don't think that was a good idea. May have shortened the life of the rubber seals in the forks, but maybe you'll get lucky with no negative effects.

[Steve]

The compression ritual is merely to assure that the oil is everywhere it should be before measuring the level. Since you had no intention of measuring the level, I guess it won't matter.

The dual springs are not unusual. Even some models of GoldWings came from the factory with them. In the early days, it was harder to make a good, progressively-wound spring, so they just stuck two springs in there with different rates. As long as you remembered to put the washer back in between them, it will be OK.

I agree on the solvent not being a good idea. Hopefully you did not leave it in there long, but the time it took to dry did not help. Might have been better for the seals to be coated sooner with oil that they appreciate. I would not bother to take the forks apart just for this, though. I would watch carefully to see if any problems show up.


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[earlfor]

I had an 81 model GS 750E that was stock with two springs in each fork tube.
Yours probably was stock that way also.

E.

[brand new bike zealot]

thanks for the info guys. bummer about the solvent. thats what was suggested by clymers, maybe kerosene for a flush instead?

[dardoonk]

I just ordered a set of Work's dual-rate springs for my Triumph. All things equal, the performance of a dual-rate spring and a progressive rate spring are virtually the same. The difference in the two is more a function of adjustability. A progressive rate spring has a set transition point between soft/hard. This isn't a bad thing, it's just a function of their design. As a progressive spring is compressed, the coils on the closer wound end meet together & the transition begins to the rest of the spring. The point where this transition begins & ends is fixed in the compression cycle. It's possible, and some riders will errantly do so, to end up with running what is essentially a single rate spring by compressing the soft portion when too much pre-load is put on a this type of spring.

I am not sure of older dual-rate springs, but the Work's set allows the transition point to be adjustable. This is done by inserting various length adjusters that fit inside the smaller spring. By having the ability to control when the transition takes place, it can be easier be set to rider preference.

Biggest drawback to Work's dual-rate compared to progressive springs - they cost twice as much.

[earlfor]

Kerosene shouldnt hurt anything. Automatic transmission fluid works well for that purpose and I can guarantee it will not harm the seals.

E.

thanks for the info guys. bummer about the solvent. thats what was suggested by clymers, maybe kerosene for a flush instead?

[beby99]

Yep...parts diagram shows you have two springs per tube:

http://alpha-sports.com/spst/1978%20GS550/25.gif

[BentRod]

My Haynes manual does talk about 2 spring suspention, and it is standard on some models. (I own an 81400) not my model, but apparently some have 2 springs per shock.

[Carter Turk]

I stand corrected on the 2 part spring. I think I was looking at the 80 1100 Dyno-jet thread as I owned one of those, and scrolled down to this one.