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Stainless Exhaust Valves

Discussion in 'The Garage' started by Jim, Feb 23, 2021 at 12:46 PM.

  1. Jim

    Jim Beyond the edge is the unknown. Here be Dragons XS650.com Supporter Top Contributor

    So... I'm building an engine and I have two different sets of exhaust valves I can use; the stock ones or these stainless steel ones. I've read here and elsewhere that the MikesXS SS valves have been known to have reliability issues. Specifically, I recall two instances where the valves literally came apart and destroyed the top end.
    So here's my question; can anybody tell me if these are the MikesXS variety of SS valves? Are they as unreliable as I've read? If these are the Mikes variety, would you use them?
    I'll add that this will be a stock motor other than cleaning up the ports and maybe some VM carbs and aftermarket exhaust. So performance isn't really the issue, reliability is.
    Thanks guys.

    ex1.jpg

    ex2.jpg

    ex3.jpg

    @grizld1 ,@gggGary ,@5twins ,@Jack ,@TwoManyXS1Bs ,@XSLeo , @650Skull ,
     
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  2. MaxPete

    MaxPete Lucille, Betty, Demi & Gretel: I ask, THEY decide. XS650.com Supporter Top Contributor

    I guess one question would be - are you certain that they are SS Jim?

    I guess my other thought is: have there been any durability problems with the stock valves and if not, then why not just use them?

    Pete
     
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  3. Liftedzuki

    Liftedzuki XS650 Addict

    Magnet test will tell you if they're stainless.

    I think I'd run oem for realibility. Im doing oem in my 700cc JE build. I will end up taking the head back off later when I have a ported /polished head/cam etc but until then all OEM engine wise.

    I'm also trying out the Hoos racing cam chain guide. Hope it's better than the OEM that likes to de laminate
     
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  4. Jim

    Jim Beyond the edge is the unknown. Here be Dragons XS650.com Supporter Top Contributor

    Non-magnetic... so yeah... stainless.
    Because I can. :sneaky: I have 'em in hand. If they're usable, why not?
     
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  5. Jim

    Jim Beyond the edge is the unknown. Here be Dragons XS650.com Supporter Top Contributor

    ?? :cautious:

    Well, in defense or that poor little guide... it took 40-50 yrs for it to delaminate. I'd call that a win for engineering.
     
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  6. Liftedzuki

    Liftedzuki XS650 Addict

    Edited my post. I meant stainless*.

    Too many 14 hour work shifts.
     
  7. jetmechmarty

    jetmechmarty What should I put here? XS650.com Supporter Top Contributor

    I can think of one reason, and I believe it's sound.
    That is, until or unless you get definitive answers.
     
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  8. jetmechmarty

    jetmechmarty What should I put here? XS650.com Supporter Top Contributor

    07839AC9-7042-4EC8-8EA4-091CF2B3418C.jpeg

    BTW, 57,000 miles and it did not fail. It’s worn out but was still doing the job. This one is OE.
     
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  9. Jim

    Jim Beyond the edge is the unknown. Here be Dragons XS650.com Supporter Top Contributor

    Btdt....
    I knew what you meant, just bein' a smart arse. :sneaky:
    Cheers.
     
  10. MaxPete

    MaxPete Lucille, Betty, Demi & Gretel: I ask, THEY decide. XS650.com Supporter Top Contributor

    Actually....not all stainless steel is non-magnetic.

    Only austenitic stainless is non-magnetic - but there are numerous grades that are magnetic. Here is a little clip that explains:

    What Makes a Stainless Steel Magnetic?

    In order for stainless steel to be magnetic, a couple of requirements need to be met:
    1. The stainless steel must have iron in it
    2. The stainless steel must have its crystal structure be arranged in a ferritic or martensitic structure.
    First and foremost, since stainless steels are a type of steel, which means they must contain iron in their chemical composition. That takes care of the first requirement. The second requirement is that the stainless steel must have its crystal structure be arranged in a ferrite or martensite structure. If a stainless steel is mostly comprised of an austenite structure, then it will not be magnetic.

    Which Types of Stainless Steel Are Magnetic?
    Magnetic and non-magnetic stainless steels can typically be grouped together based on the type of stainless steel. The following types of stainless steel are typically magnetic:
    1. Ferritic Stainless Steels such as grades 409, 430 and 439
    2. Martensitic Stainless Steel such as grades 410, 420, 440
    3. Duplex Stainless Steel such as grade 2205
    Ferritic Stainless Steels:
    Ferritic stainless steels are typically magnetic as they have large quantities of ferrite in their chemical composition. Ferrite is a compound of iron and other elements. The combination of a ferritic crystal structure with iron makes ferritic stainless steels magnetic. However, some ferritic stainless steels may have a weaker magnetic pull than normal carbon steel.

    Martensitic Stainless Steels:
    Many martensitic stainless steels are magnetic. The unique crystal structure of martensitic steels can be ferromagnetic if iron is present. Since stainless steel is a type of steel, there is an abundant amount of iron in its make-up. This makes many martensitic stainless steels magnetic.

    Duplex stainless steels:
    Duplex stainless steels are typically magnetic because they contain a mixture of austenite and ferrite. The substantial amount of ferrite (which is magnetic) contributes to Duplex steels being magnetic. However, since duplex stainless steels have more austenite than ferritic steels, they may be slightly less magnetic.

    Austenitic Stainless Steel:
    Austenitic stainless steels have a high amount of austenite which makes them mostly non-magnetic. Even though grades such as 304 and 316 stainless steel have high amounts of iron in their chemical composition, austenite means they are non-ferromagnetic. However, if the crystal structure of an austenitic stainless steel is changed through work-hardening or special thermal treatment, then ferrite can form in some locations making the steel partially magnetic.
     
  11. 5twins

    5twins XS650 Guru Top Contributor

    20,618
    13,043
    813
    ..... and judging by the wear on that one side, not centered correctly when assembled. Honestly, I don't think the factory bothered to do that, lol, judging by the number of old guides I see worn on one side like this.
     
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  12. gggGary

    gggGary I'm listening, change my mind XS650.com Supporter Top Contributor

    I know nothing but I'll try to prove it.
    Wasn't the failure deal a spun welded head shank joint that could let go?
    Stock valves do pretty well.
    xsruinedjug 008.jpg
    Mostly..........
    @kopcicle should WILL have an opinion.
     
  13. Liftedzuki

    Liftedzuki XS650 Addict

    Haha I figured so. I wish I was working on my engine right now. It'll have to wait til Saturday though. I did a bunch of research and I found one place with aftermarket valves I might consider when I do a fully built upper end.
    http://www.smedspeed.co.uk/valve.html
     
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  14. Bewarethemoon

    Bewarethemoon XS650 Junkie XS650.com Supporter Top Contributor

    I have a set of these waiting to go into my engine, look great! Happy to post photos if the group wishes?
     
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  15. Liftedzuki

    Liftedzuki XS650 Addict

    That would be great.
    Are you going with different valve guides or valve guide liners?
    Local machine shop cutting the valve seats?

    Thanks Spenser
     
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  16. Bewarethemoon

    Bewarethemoon XS650 Junkie XS650.com Supporter Top Contributor

    I’ll take them tomorrow night when I have an evening in the workshop

    I’m using bronze valve guides, I’ll send the head out for the seats to be cut & lead conversion by Rolan Alsop’s in Chobham, Surrey.
     
  17. Jan_P

    Jan_P XS650 Addict

    364
    545
    93
    Sweden
    So performance isn't really the issue, reliability is.
    Thanks guys.

    I've read here and elsewhere that the MikesXS SS valves have been known to have reliability issues.

    I have all my life heard of substandard " Pirate Parts " do You have that expression in the US
    First time was in the 60 ies pushrods for brittish bikes
    My view as a rule of thumb is that stock is designed manufactured inspected according to the company's standard.
    Usually the non stock parts are cheaper .. and at times the quality can be acceptable

    When it comes to valves there is a very small play in the valve guide .And inserting a material different than the designer have taken into account .Might expand differently.
    There can also be more difficult welding procedures. In the manufacturing

    if I had sets of Stock valves and Non stock of uncertain origin .Perhaps manufactured in a shed in a back alley in China with more items not being within the right specs.
    For me it is only an issue if the stock parts is worn or not available Otherwise I go for stock ..
    Especially engine parts and if Reliability is a goal and heard that the ones Non stock can have problems.
    Here are competent experienced people .But I have seen people trying something else .And ended in big problems damaged engines.
    Situations that was not possible to repair within reasonable costs. Scrapping the whole machine.
    Garys nr #12








     
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  18. Liftedzuki

    Liftedzuki XS650 Addict

    I'm actually in the USA, looks like you're UK. I just randomly came across those valves since they seem like the only aftermarket option that would be quality. Shipping can't be too bad on valves.

    Do you have a build thread on the engine?
     
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  19. GLJ

    GLJ Never go faster than your guardian angle can fly. Top Contributor

    Unless you can find the guy that bought them it will be all but impossible to figure out. Even if you found the guy and he didn't buy them from Mikes it wouldn't mean the are not the same as Mikes sells.

    Since reliability is most important I don't think you can do any better than OEM. My :twocents:
     
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  20. grizld1

    grizld1 Grumpy old man Top Contributor

    Jim, when I run into a technical question that my go-to references and people can't answer, I don't roll the dice and risk my motor--I consult the Tarot deck. Let me read for ya. I'll give 'em a quick shuffle,cut and cards, and--Oh hell, it's the Devil! The reading is certain: You'll be strongly tempted to use that valve. Don't do it!
     
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