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Thread: 04 450 SMR Head Question (bronze guides)

  1. #1
    KTMTalk Member WelderShane's Avatar
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    Default 04 450 SMR Head Question (bronze guides)

    I have an 2004 450 smr (unknown hrs.) that I bought last year. I raced it pretty good last season (not pro level) on kart tracks. Ran great, strong, blast to ride. I read that the early model rfs engines have the ticking time bomb bronze valve guides. I pulled the carb off to take a look today, and I would assume these are bronze guides? I have attached a few pics of the inside of my intake? I see the part numbers have changed on the valve guides. Did Ktm ever update the valve guides or are thy still bronze? Is the failure rate pretty high with the bronze guides? I guess it would be a good idea to get these swapped out before they become a problem.
    Attached Thumbnails Attached Thumbnails Resized_20200112_130138.jpg   Resized_20200112_130906.jpg   Resized_20200112_125738.jpg  

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    Lifetime Team KTMTalk caflash's Avatar
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    Default Re: 04 450 SMR Head Question (bronze guides)

    Quote Originally Posted by WelderShane View Post
    I have an 2004 450 smr (unknown hrs.) that I bought last year. I raced it pretty good last season (not pro level) on kart tracks. Ran great, strong, blast to ride. I read that the early model rfs engines have the ticking time bomb bronze valve guides. I pulled the carb off to take a look today, and I would assume these are bronze guides? I have attached a few pics of the inside of my intake? I see the part numbers have changed on the valve guides. Did Ktm ever update the valve guides or are thy still bronze? Is the failure rate pretty high with the bronze guides? I guess it would be a good idea to get these swapped out before they become a problem.
    100% failure rate. 50 hours. Damages the valves edges wobbling in the guide as the valve hits the seat at an off angle.

    Ti valves are not regrindable. Replace only.

    I have ti heads with iron updated guides and good ti valves in stock.

    Replacing the lighter valves requires heavier springs to go with the heavier valves. Looses power.

    If you kick start your bike and stop mid kick your kick starter lever stays where it was.

    With the heavier tension springs to match the heavier valves the kick lever will push your leg back up as the heavier valve springs turn the cam backwards.

    stop riding the bike. Avoid more valve damage. Needs to come apart and see how bad the wear is.

    Or ride it till it has a failure. Part it out then.

    Have a leakdown test done. Normal is a rod kit, cylinder replate, piston and fix head. If the rod is tight and the piston and cylinder are ok then itís just the head issues.

    Guides and ti valves are in the fiche here above. Plus install of course.
    Rfs DocBob

    Current: rebuild 560 smr motor
    520 to 613.p

    ALL rfs engines available....other than 250ís


    2004 613 rfs titled
    2002 520 rfs titled
    2005 483 rfs titled
    1996 620 lc4 titled
    (2)2007 613's in the works

  4. #3
    KTMTalk Member DJH's Avatar
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    Default Re: 04 450 SMR Head Question (bronze guides)

    The fix is the 2006 guide, I cut snap ring grooves in them which KTM used to do. If this is done when they are fairly low hours cost is not huge. Changing to steel valves is cheaper but for motard you need the TI. The sooner you do this the less it costs, common deal at 50 hours we reuse valves, at 75 hours need one valve, at 100 hours two valves etc
    [URL=http://www.djhcyclesport.com
    Former Husky Dealer in the '70's, currently Sell Real Estate, Seattle area and as a hobby business I manufactor cam chain tensioners for the KTMs, do Carburetor modification & setup and valve work on KTM & Husky 4 strokes. Full stock of parts for the KTM's. My rides are; Cadillac Escalade (the 1/2 pickup version), 72 ElCamino 454SS, and Triumph 1050 Sprint ST, Iron Butt member

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    KTMTalk Member WelderShane's Avatar
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    Default Re: 04 450 SMR Head Question (bronze guides)

    Thanks for the reply guys I appreciate it. It looks like this engine might of been torn into in the past, at-least the top end. Just by looking at a few marks on bolts and such. Is there any way of knowing if I have stainless valves by just looking? Would you still use bronze guides with stainless valves? Was it common to do the stainless swap, especially in motard use? The only reason that I ask is I'm not sure what exactly I have. Was this possibly rebuilt at one time and stainless valves put in? I had to adjust valves once last season, other then that its been fine, and still seems like i have plenty of adjustment left. This is the first RFS I have ever ridden, so i don't really know the difference in power wise with ti valves vs stainless. I guess this is one of the joys of buying a used bike and not knowing the history. The prior owner didn't own it long (maybe 2 months), so he wasn't very helpful with knowing the history of the bike. I just hate tearing into something if nothing is wrong, especially if it was recently rebuilt. Bike runs strong and is tons of fun, but I would hate to have a valve stick and grenade the whole engine.

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    Lifetime Team KTMTalk caflash's Avatar
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    Default Re: 04 450 SMR Head Question (bronze guides)

    You could take the rear valve cover off and look in there? Valve springs have a gold color and numbers on them? Can you push the top of the spring aside with a screw driver? Wiggle it?
    Rfs DocBob

    Current: rebuild 560 smr motor
    520 to 613.p

    ALL rfs engines available....other than 250ís


    2004 613 rfs titled
    2002 520 rfs titled
    2005 483 rfs titled
    1996 620 lc4 titled
    (2)2007 613's in the works

  7. #6
    KTMTalk Member DJH's Avatar
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    Default Re: 04 450 SMR Head Question (bronze guides)

    The steel valve conversion idea is fine for a trail rider but motard needs the Ti to survive the high RPMs
    When doing a steel conversion one also needs to factor in the cost of valve springs to manage the weight of the steel!
    [URL=http://www.djhcyclesport.com
    Former Husky Dealer in the '70's, currently Sell Real Estate, Seattle area and as a hobby business I manufactor cam chain tensioners for the KTMs, do Carburetor modification & setup and valve work on KTM & Husky 4 strokes. Full stock of parts for the KTM's. My rides are; Cadillac Escalade (the 1/2 pickup version), 72 ElCamino 454SS, and Triumph 1050 Sprint ST, Iron Butt member

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    KTMTalk Member WelderShane's Avatar
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    Default Re: 04 450 SMR Head Question (bronze guides)

    I took the cover off and took a look. They do appear to be goldish and have white numbers written on them. I believe it says 046 but its hard to read.
    Attached Thumbnails Attached Thumbnails Resized_20200114_183140.jpg   Resized_20200114_184203.jpg  

  9. #8
    KTMTalk Member DJH's Avatar
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    Default Re: 04 450 SMR Head Question (bronze guides)

    That is the spring set used with the Ti valves, they are excellent springs but not to be used with steel valves
    [URL=http://www.djhcyclesport.com
    Former Husky Dealer in the '70's, currently Sell Real Estate, Seattle area and as a hobby business I manufactor cam chain tensioners for the KTMs, do Carburetor modification & setup and valve work on KTM & Husky 4 strokes. Full stock of parts for the KTM's. My rides are; Cadillac Escalade (the 1/2 pickup version), 72 ElCamino 454SS, and Triumph 1050 Sprint ST, Iron Butt member

  10. #9
    Lifetime Team KTMTalk caflash's Avatar
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    Default Re: 04 450 SMR Head Question (bronze guides)

    I sourced, ported and rebuilt a quantity of your head long ago. With Iron guides.

    not economically feasible for most to have these rebuilt after damage.

    As the guides wore the valve ďhuntedĒ for the valve seat causing all the springs forces to be concentrated on only a small part of the valves edge.

    That concentration of force dents the soft ti valves edge.

    Those ti valves have a hard coating that actually withstands the springs force if spread out all the way around the valves edge. Not localized.

    Very reliable with good ti valves and iron guides.

    Push the top of the valve spring retainer sideways to see if you can move it.

    If you can the guide is worn. If worn the valves edge is cupped. It may still seal for a while. The coating can itself flex into the groove created.

    As DJH posted the use needs the ti valves for the high rpm and to retain the engines power.
    Rfs DocBob

    Current: rebuild 560 smr motor
    520 to 613.p

    ALL rfs engines available....other than 250ís


    2004 613 rfs titled
    2002 520 rfs titled
    2005 483 rfs titled
    1996 620 lc4 titled
    (2)2007 613's in the works

  11. #10
    KTMTalk Member WelderShane's Avatar
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    Default Re: 04 450 SMR Head Question (bronze guides)

    Thanks alot DJH, and Caflash. I really appreciate the answers and help for everything about this topic.

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