Stainless VS Ti Valves Spring Use

m1ke20012
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m1ke20012
So I got a set of SS valves for a 2013 KX250F to replace the stock Ti but now i’m wondering if I will need upgraded springs to accommodate these, i’d like to reuse the stock springs but people say both yes you can and some say no you can’t. One thing that interests me is that HD valves springs or aftermarket valve springs don’t list any spring rates or suggestions for what they should be used on so it makes me wonder if it really matters, as compared to a car. Also this bike is not ridden hard is used by a middle aged gentleman who will ride mostly off-road with his children so the valves aren’t being used hard or constantly bouncing off rev limited despite being a 250. Thanks.
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kb228
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kb228 12/12/2019 7:25am
12/12/2019 7:25am
Stiffer springs are used to avoid fluttering. They make sure stainless valves close each cycle.

If you are in fact riding the way you say you are you might be ok. I cant say id risk it in my own bike though.

Usually stainless valves come in a kit with the springs. What you can likely do is go to ProX and get a set of springs for stainless steel valves.
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Keith72
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Keith72 12/12/2019 7:48am
12/12/2019 7:48am
Send your head to Fastheads.com. Top quality work.
harescrambled
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harescrambled 12/12/2019 10:56am
12/12/2019 10:56am
m1ke20012 wrote:
So I got a set of SS valves for a 2013 KX250F to replace the stock Ti but now i’m wondering if I will need upgraded...
So I got a set of SS valves for a 2013 KX250F to replace the stock Ti but now i’m wondering if I will need upgraded springs to accommodate these, i’d like to reuse the stock springs but people say both yes you can and some say no you can’t. One thing that interests me is that HD valves springs or aftermarket valve springs don’t list any spring rates or suggestions for what they should be used on so it makes me wonder if it really matters, as compared to a car. Also this bike is not ridden hard is used by a middle aged gentleman who will ride mostly off-road with his children so the valves aren’t being used hard or constantly bouncing off rev limited despite being a 250. Thanks.
SS valves are substantially heavier than Ti valves. You need the heavier springs for sure. With the increased mass of the SS, you might end up with valve float even in the midrange
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adam8781
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adam8781 12/12/2019 11:43am
12/12/2019 11:43am
i use pro x valves and springs in alot of customers heads, zero issues. yes you need stiffer springs
NoMuff2Tuff
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NoMuff2Tuff 12/14/2019 6:27am
12/14/2019 6:27am
Pretty much with these guys said. You can go on Kimble Whites web and they list the seat and open pressures for both Ti and steal. The steal valves will last longer but you will loose some over rev after peak power from the weight of the heavier valves.
Lasse
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Lasse 12/14/2019 3:50pm
12/14/2019 3:50pm
harescrambled wrote:
SS valves are substantially heavier than Ti valves. You need the heavier springs for sure. With the increased mass of the SS, you might end up...
SS valves are substantially heavier than Ti valves. You need the heavier springs for sure. With the increased mass of the SS, you might end up with valve float even in the midrange
That, and the rest of the valve train won't be dimensioned for the extra weight of the SS valves.

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