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Thread: ESE's works engine tuner

  1. #34696
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    19th June 2011 - 00:29
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    Quote Originally Posted by wobbly View Post
    The plater here would vee the crack out , weld it up , bore and grind it back , and replate .
    Easy job.
    no problem's welding through and through to avoid re-cracking ?

  2. #34697
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    8th February 2007 - 20:42
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    A few cylinders are simply a bad design ( 4DP Yamaha TZ ) that crack no matter what , but the weld material is stronger than the cast alloy , so usually the weld is more reliable.
    Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.

  3. #34698
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    20th January 2010 - 14:41
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    Quote Originally Posted by JanBros View Post
    no problem's welding through and through to avoid re-cracking ?
    Closer to your home
    https://www.kiwibiker.co.nz/forums/s...post1130610635
    Quote Originally Posted by Katman View Post
    I reminder distinctly .




    Kinky is using a feather. Perverted is using the whole chicken

  4. #34699
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    2nd April 2012 - 00:54
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    Quote Originally Posted by wobbly View Post
    A few cylinders are simply a bad design ( 4DP Yamaha TZ ) that crack no matter what , but the weld material is stronger than the cast alloy , so usually the weld is more reliable.
    Without knowledge of the cylinder material, heat treatments or weld metal material & associated weld heat inputs that may / will actually anneal the cylinder about the weld reworks, nor knowing if the welding has been performed correctly I’m not so sure your statement is correct ��*♂️
    One thing for sure is the shrinkage stresses of the solidifying weld / welds upon a heat treated cylinder rework is akin to over tightening a con rod bolt & expecting it to still perform its role adequately, it can not.
    However normalising & reheat treatments may fix these issues from welding, although then the correct weld metal filler wire would be required & I’m yet to know of a cylinder plating / repair shop to having adequate knowledge of welding to do anything other than create a soon to fail rework whilst billing the owner for the privileged of at best a rework but certainly not what I consider the meaning of the word repair is.

  5. #34700
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    3rd January 2012 - 01:25
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    Quote Originally Posted by JanBros View Post
    it 's just for having some off-road fun, not to ride it at max like a pro.
    Why not just leave it as it is?

    I have done the exact same thing in the past and ran a cylinder with such a crack in the exhaust bridge for two seasons. It has been running with the cracks like this before for some time at the previous owner and without problems anyway. On mine, I just made sure it would keep doing it by relieving the bridge in the cracked area with some sandpaper.

    After that, I put some more work into the cylinder and also had the crack repaired at the plater. I ran the cylinder for another couple of seasons without any issues afterwards. Plating and repair was done at http://www.langcourt.com in GB which is also a bit closer to where you are located. They are experienced with such kind of repairs, just tell them NOT to grind / deburr your transfer port windows after the re-plate, as they (or one of their staff) are / were usually quite generous in doing it.

  6. #34701
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    19th June 2011 - 00:29
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    Quote Originally Posted by Haufen View Post
    Why not just leave it as it is?
    don't think I would feel comfortable, always thinking that at the edges of the crack the plating would start to come of.

  7. #34702
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    20th June 2020 - 07:10
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    Quote Originally Posted by Haufen View Post
    They are experienced with such kind of repairs, just tell them NOT to grind / deburr your transfer port windows after the re-plate, as they (or one of their staff) are / were usually quite generous in doing it.
    I always engrave cylinders in an obvious place “plater no chamfer”. If I forget, they come back with a massively aggressive radius. Some guys are good, some are braindead. Also I would not be afraid of welding cracks. If done correctly they will not have issue. Bevel away as much as you need then repair. Bridges can be built up from nothing and be plated. Had better luck with 4043 filler not getting ruined by the stripping tank FYI, but if you are having the plater do all the labor you do not even have to know that. I would 100% go for the weld/repair/replate unless you know your plater is a hack. You could always go welded in aluminum sleeve too.

  8. #34703
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    3rd January 2012 - 01:25
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    Quote Originally Posted by JanBros View Post
    don't think I would feel comfortable, always thinking that at the edges of the crack the plating would start to come of.
    So was I. But I as a student, I was short of money, too So I worked the edges of the crack with sandpaper and used the cylinder for dynoing only, at first. But as that went perfectly well, promoted it to the real race engine, soon.

    If you have it repaired at langcourt, they will weld the crack and re-shape to original shape as well.

    I am not sure about the sleeve option. This seems to come with the highest cost and effort and give a compromised result (sleeved cylinder) in the end.

    Maybe just getting another used cylinder would be an option, too? Are these hard to find?

  9. #34704
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    6th October 2015 - 13:42
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    Cracked Bridges

    Quote Originally Posted by JanBros View Post
    bought a KDX200 but sadly there are 2 cracks between the exhaust ports on the left. I'm in doubt as to whether have them welded and replated or have it sleeved. if welded, will they weld it through and through and not leave parts of the crack that can grow again? and if they weld it through, I'm in doubt as to if it will not harm the flow if the weld protrudes, hardly being able to correct that.
    I know the downsides off sleaving, but it 's just for having some off-road fun, not to ride it at max like a pro.

    also first time I've seen a raised exhaust port on a standard cylinder from the early '90ies

    Janbros, as Wobbly mentioned the platers can weld these cracks. The KDX Cylinder Exhaust is very similar to the KX500 with the dual sub ports either side of the main port and notorious for cracking there in addition to the intake bridges. The repair done by most of the platers here in the states are quite remarkable and FAR better than the original casting. I’d have it repaired and replated before a ring could snag itself on that.

  10. #34705
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    19th June 2011 - 00:29
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    also had a response from Jan Luyten (from Luyten import in Belgium and the son of the Luyten 125cc engine) and they say they most of the time re-crack.
    gonna leave it aside for a while and see if a 200 or 220 cyl pops up somewhere.

  11. #34706
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    8th February 2007 - 20:42
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    The replating process is full of pitfalls , but most are well versed in what is needed.
    Yes , 4043 is the welding rod of choice , and that works very well.
    The important deal is getting the cylinder up to a temp , high enough to prevent excessive stress from weld pool shrinkage , but to not destroy the heat treat.
    NZ Cylinders here , heat , then weld , then run thru the bore and or grind away most of the added excess filler , then prior to final hone they do a micro piening process to reduce the localized stresses.

    One big issue may platers dont do properly is that as they VERY rough hone the bore ( for nicasil adhesion ) this removes much of the chamfer on the Exhaust port alloy timing edges.
    So I have to give written instruction every time , for them to rechamfer this in the alloy prior to plating - if they dont , then as soon as I remove the chrome flash lip inside the port
    then there is insufficient chrome depth within the bore to put on the required vertical chamfer.

    And as all you guys on here should know by now , you dont need ANY chamfer on transfer ports - instant power loss , and no effect at all on ring life.
    Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.

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