primary clutch spring height

[STAIN]

Does anyone know the installed height and the full shift out height of the primary springs in the Sidewinder, Apex/Rx-1 clutch's?
I want to do some comparisons and these are the height's I would like to test at.

 

[Motorhead]

Does anyone know the installed height and the full shift out height of the primary springs in the Sidewinder, Apex/Rx-1 clutch's?
I want to do some comparisons and these are the height's I would like to test at.

Bottom, Gold red Gold stock on my 2017 LTX-LE.

 

[justinator]

Never saw yamaha show measured heights but for reference dalton does 2.888” and 1.593” and using those measurements the stock sidewinder measures 57/115 vs 55/105 yamaha publishes. Could be a good reference measurement.

 

[STAIN]

The reason I will use installed height is that it seems, to me anyway, that with all the different heights on the springs why measure them all the same preload?
Wouldn't a taller spring have a higher installed preload than a shorter one?
Wouldn't installed height preload, full shift out and rate be the best comparisons?
Am I wrong or overthinking this?

 

[Fords4life]

I dont know if you and i are correct in our thinking but i agree, i use hieghts and rates for selection, if i like the shift thru the spring i have but need more start rpm or more finish rpm i just copensate more or less finish or start spring force, but like i said if i like the rate thru out i keep the rate spread between the two points close to the same.

 

[Stubbs]

The reason I will use installed height is that it seems, to me anyway, that with all the different heights on the springs why measure them all the same preload?
Wouldn't a taller spring have a higher installed preload than a shorter one?
Wouldn't installed height preload, full shift out and rate be the best comparisons?
Am I wrong or overthinking this?

I’ve always assumed that the preload listed in all of Yammy’s spring charts was the number the spring had at installed height in the clutch, not static height at rest. If this wasn’t the case that preload number would be basically meaningless for comparison’s sake.

 

[justinator]

I’ve always assumed that the preload listed in all of Yammy’s spring charts was the number the spring had at installed height in the clutch, not static height at rest. If this wasn’t the case that preload number would be basically meaningless for comparison’s sake.

Thats how I have always looked at it and I have a pretty big selection of primary springs that Ive experimented with. Using the yamaha chart the springs have always acted the way I would of expected them too with no surprises. Higher rate springs have larger coil diameters to have a shorter spring still produce higher finish forces. Never noticed much difference elsewhere other than engagement and wide open rpms being what I expected them to be according to published specs.

 

[74Nitro]

If you do the math from Motorheads post it would be as follows -
Installed height would equal 55 divided by 1.50 = 36.66
110.1 - 36.66 = 73.5mm

Fully shifted height would equal 105 divided by 1.50 = 70
110.1 - 70 = 40.1mm

 

[justinator]

And those numbers converted to inches just about equals the measurements dalton uses (2.888 and 1.593)