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"Ciscos", alternative power valve spring

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I mentioned in another thread that I had fitted a Ciscos power valve spring made by a well known Yamaha tuner in Australia. The shop is called Ciscos and from what I have read (and cross examination before I dumped my YZ on him) they have been doing factory Yamaha work for years, including for Mr Reed, Mr Metcalfe and lots of top Australian riders. I had an engine built with the brief "I want a blue KTM". (ie smooth, torquey, no hit, luggability etc etc) Except mine is WAY better.

Steve recommends a Vforce reed block at the same time to get it even smoother but he is a big proponent of a matching bag of mods rather then bits and pieces added and subtracted.

I hope this works....

yzpvspringstock.jpg

Edited by Snelens

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That's a tiny picture.

From what I can tell it looks like it did a great job of filling in the flat spot and hit in the midrange.

  • Was this your bike?
  • Was this with the spring only, or spring and V-Force?
  • Any jetting/timing tuning between the runs?
  • Do you know if this is a softer spring, opening the valve earlier? Or a stiffer spring/later opening?

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That's a tiny picture.

From what I can tell it looks like it did a great job of filling in the flat spot and hit in the midrange.

  • Was this your bike?
  • Was this with the spring only, or spring and V-Force?
  • Any jetting/timing tuning between the runs?
  • Do you know if this is a softer spring, opening the valve earlier? Or a stiffer spring/later opening?

It sounds like it was spring only. I would like to know, that's an impressive power curve.

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Steve's dyno always looks low compared to others

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Sorry no idea on before / after jetting specs. This wasnt my bike but a graph showing the stock motor with PV spring as the only mod. No idea on the spring tension but he did show me a collection of test springs.

My bike went from a tired stocker to the full build, with no dyno time in between, so not a great example for this thread. Reminds me that I need to get my actual graph from him as well.

I'm happy to put a bigger picture up but NFI on the "how to" bit. Any pointers? I have it as a PDF.

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I didn't think that spring made much difference to my 295.

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Put your bike on a boat and the dyno will probably prove otherwise....But at 295CC it probably has so much more torque...

BRM, you know Steve wouldn't do it unless it worked, he doesnt fark around with bovine excrement.

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Put your bike on a boat and the dyno will probably prove otherwise....But at 295CC it probably has so much more torque...

BRM, you know Steve wouldn't do it unless it worked, he doesnt fark around with bovine excrement.

On the dyno it could show a difference, based on the ride I didn't notice much difference.

Steve will also tell you the spring should be changed every 100 hours or so.

How much did you pay for the spring? OEM is only a few dollars.

Photo of standard spring and Cisco's spring

P1290011.jpg

Edited by BRM

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On the dyno it could show a difference, based on the ride I didn't notice much difference.

Steve will also tell you the spring should be changed every 100 hours or so.

How much did you pay for the spring? OEM is only a few dollars.

Photo of standard spring and Cisco's spring

P1290011.jpg

Thats going to be a softer spring as it has an extra coil.

My RM has adjustable preload on the PV spring.I back it off a bit, smooths out the mid hit.

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So if Cisco's is softer and my 13yr old spring is worn out, wouldn't that be kinda the same? :lol:

I'll gladly replace mine if it would soften the hit.

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where do you get these springs and how much

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Can't remember the exact cost, maybe $70? For a spring by itself its expensive but for the research hours, improvements & the amount sold, its cheap in my eyes.

Order from him on info@ciscos.com.au

Edited by Snelens

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The spring on the right should be stiffer just by looking at it. Tighter wound coils, larger wire diameter. Looks like a taller solid height though. I wonder how close it comes to coil binding?

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The spring on the right should be stiffer just by looking at it. Tighter wound coils, larger wire diameter. Looks like a taller solid height though. I wonder how close it comes to coil binding?

The one on the right is softer as there are more coils therefore the spring is easier to compress.

Also wire diameter is slightly thinner.

Height is the same. The spring on the left has done hundreds of hours.

There is no binding, the springs were measured agains the movement of the power valve actuator.

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