Silly spring question....the problem with buying used

[Rcannon]

I noticed the fork springs in my 1997 YZ 250 are a beautiful , black color. I do not believe the stock Yamaha springs are coated.

How can I tell what weight these are. There are no markings on them at all! The wire diameter measures the same as a set from a stock YZ 250f. Thank you!!!

 

[MikeT]

GREAT question. I am latching on to see the answer..

 

[marcusgunby]

You need to take them to a tuner and have tested for the rate.

 

[tankslapper]

Eibach springs are sometimes a black colour and usually have white lettering on 1/4 of way down from one end, these are great springs!

 

[Rcannon]

Marcus, I know your right, but how can I justify that? I cannot think of anyone locally that will test them. So, UPS them 10.00...spring test...probably at least 20.00. Then, what if I find out they are .37's or something like that.

I think the easiest is to chuck them into the local pnod and do not look back. The thing is, this will not work either. I will always wionder if they were the perfect spring.

I had a grandfather that had a similar dilema building a tractor engine. He could not remember if the pistons went with the markings foreward or backwards.....Honestly, no bs, he put two in foreward and two in backward. Maybe I need to do this?

 

[MACE]

Ride the bike and see if it feels right. That's what matters. :cool:

If you have a fish scale or a good dial scale you can do a ghetto check...

How about you have a decent bathroom scale... Take one leg and mark the slider one inch from the wiper. Loosen the air bleed. Now put the leg vertical and push down until you have deflected the fork to the one inch mark and note the scale reading. Make another mark two inches down and repeat. Ok now subtract the two readings and you get the rate in pounds per inch. (You subtract to eliminate the leg weight and preload effects.)

To get kg/mm divide lb/in by 56

Each .02kg/mm step is like 1.1 lb so you have to be able to measure with pretty good accuracy to really know what your rate is. At any rate (pun intended) you should be able to tell a .37 from a .46

 

[marcusgunby]

Like mace said if it rides good then who cares?

 

[tankslapper]

Rcannon, what is the point in throwing your springs away if they feel good on the track but are just the wrong color?

 

[Rcannon]

I wuld only throw the springs out if I did not know the weght of them. To me, it would feel like buying one of those 1 dollar grab bags filled with ???? at 7/11.

I am going to try the scale method. The springs feel slightly soft in my bike, so I am guessing the previous owner installed softer springs than the bike came with. After all, who would install a different spring identical to the stock springs?

 

[marcusgunby]

On a 97 someone could have installed stiffer springs when new then a few years down the road a new owner installed some that are std rate from a different supplier.In the end the forks are a little soft- you could increase oil heights if its just a bottoming problem.If its hanging down in the stoke you could preload them a bit.If it soft throughout the travel you could use Mobil 1 ATF.None of these things cost 10% of the cost of the springs.
Even std springs are not exactly what the manufactures say.I think you are concerning your self too much in the rates and not enough on how they perform.

 

[Rcannon]

I had a wonderful day on this bike today. My first real day on a track. The bike did well, except for some bottoming that was a bit harsh. I think I will raise the oil level a bit and see what happens.

All in all, the modern bikes are amazing. I still cannot believe how nice this machine is compared to my DR 350. The suzuki had a decent motor, but the suspension was nothing like the YZ.