Can someone tell me how to use this valve spring tester?

[Paul.S]

I just bought a mini Proform valve spring tester to test my springs. You simply put it in a vise and compress the valve spring against the measuring pad until you compress it to testing length which in this case is 1.26" for the outer spring on a gs1100. So, I did exactly that but the scale is only reading about 4-5 psi. Factory specs are 14.3-19.6 and I know mine are not that worn out as I spun 11,000 rpm a few times with .345 cams without a problem. Obviously having only 4-5 pounds would not work at all anyways. PO said they put in heavier springs too. So, are you supposed to do a mathmatical equation to turn the PSI reading on the gauge into actual pressure? Am I supposed to figure the area in square inches of the measuring pad and multiply that by my reading? If that were the case the pad is 2.47 square inches and multiplying that by my 4-5 pound reading would still only give me about 12.35 pounds. Does anybody know what I am doing wrong? If not, I will call proform tomorrow and put their answer back on here.

 

[Paul.S]

I just looked at it again and I didnt realize the very first mark on the scale is actually 5 psi so it was actually reading about 7.5psi which when multiplied by 2.47 gives you 18.53 so maybe that is how it is supposed to be used. Unfortunately, this is the smallest range valve spring tester I could find on the internet and it is way too big to accurately test these springs.

 

[Steve]

PSI is usually for pressure, not force. :-k

I would think you need something that is measured strictly in POUNDS, not PSI.

.

 

[Paul.S]

Well I just called Proform and they said you don't have to do any math and the reading in PSI is the exact same as pounds of force. So, I am thinking Suzuki gives the wrong specs on what length the springs need to be when checking them.

 

[Steve]

You said you were measuring the spring at 1.26". Is that the normal length of the spring (valve closed) or is it the compressed length (valve open)?

I don't know what the specs are, but I would think that about 20 pounds of spring pressure holding the valve closed might be about right.

However, there should be considerably more pressure when the valve is open, so crank your vise together to a spring length of 0.915" to see what the gauge reads.

That is assuming a 1:1 ratio on the rocker, which I don't think is correct. If the ratio is 1.6:1, crank your spring down to a length of 0.706 and check the pressure.

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