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Valve bounce, maybe? stuffed two valves!

Discussion in 'The Garage' started by kevski, May 21, 2020.

  1. kevski

    kevski XS650 Addict

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    Went out for a spin on Sunday, and what a bad one it was, on the way back home about a mile from home when the engine started rattling big time and lost a cylinder, limped home and could hear it was the left side i thought the motor was toast, only done about about 300 miles since rebuild, off with valve covers, left exhaust valve not closing hence the rattling, so off with tank, seat, panels, exhausts, brake lever, footrest and everything needed to enable motor removal, drain oil, nice and clean, Monday motor out top end off, had to cut the valve to drop it out bent both ends, guide has galled and valve obviously hung up and been hit by the inlet as it has the witness mark on it, the top was rebuilt and the valves and seats done by a very reputable engine builder, new stainless heiden valves, there was a good oil supply i always check this with open tappet covers, cam timing and tension fine, engine timing fine, carburation good, so what caused this is a mystery, only thing i can think off is valve bounce, i have a used head coming and have ordered new valves and a guide to rebuild the damaged one, any thoughts gentlemen?
     
    Jim, Paul Sutton and gggGary like this.
  2. GLJ

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

    How many RPMs were you running when this happened?
    The valve was bent above the top of the guide?
     
    Jim, gggGary, thuban and 1 other person like this.
  3. grizld1

    grizld1 Grumpy old man Top Contributor

    Ouch! I feel for ya, kevski. More questions: Were the collets and collet groove on the bad valve intact, is the camshaft stock, and if the cam isn't stock, were compatible valve springs installed?
     
    Jim, Paul Sutton, gggGary and 3 others like this.
  4. kevski

    kevski XS650 Addict

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    Valve bent both ends hence having to cut the top, .75 oversize pistons, stainless valves, heiden strainer, paper oil filter heiden, boyer ignition, cam is stock, retainers and collects remained in place, I do accelerate hard and rarely go over limits, this xs I have only had up to about 90mph on only one occasion, but normally only drive at about 60 mph.
     
    Jim, Paul Sutton and gggGary like this.
  5. thuban

    thuban Horse Scratcher XS650.com Supporter Top Contributor

    Oh Man, that really sux big time! Pix would help!
     
    Jim and gggGary like this.
  6. GLJ

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

    Any of the other guides show any galling?
    You got any pics?
     
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  7. kevski

    kevski XS650 Addict

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    Will try to get a few pics tomorrow, all other guides are fine with the valves able to slide under there own weight through the guides, my only thought is there may have been a problem with the valve even though they were new.
     
    Jim, gggGary and thuban like this.
  8. GLJ

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

    One last question.
    Did it start making noise at the exact same time as it dropped the cylinder or did you feel a miss and then noise?
     
    Jim likes this.
  9. Jack

    Jack XS650 Junkie Top Contributor

    What valve springs are you using and what valves?
     
    thuban, Jim, kevski and 1 other person like this.
  10. kevski

    kevski XS650 Addict

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    Just clattered and cylinder dropped at same time, stock valve springs an valves are stainless from Heiden tuning.
     
    thuban, Jim, GLJ and 1 other person like this.
  11. kevski

    kevski XS650 Addict

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    All other guides are fine. 20200522_071128.jpg 20200522_071311.jpg
     
  12. Jack

    Jack XS650 Junkie Top Contributor

    Those valves are complete junk as I've seen the valve heads pop off,valve stem out of spec . Go buy some qaulity Kibblewhite valves or buy from smedespeed(spelling) from the UK or the company on the euro ebay selling good quality xs SS valves. Replace the cheap stock V/Ps with either kibblewhite springs or any alternative spring available over there. You need to replace those guides. You don't build a engine with substandard parts and expect
    it to live long. I have an alternative spring that I'll be using but requires Moly retainers and shortned bronze valve guides. Schumann Motor works has the moly retainers with locks, Kibblewhite bronze guides and BWM single spring combine with stock inner spring.
     
    Last edited: May 22, 2020
    grizld1, MaxPete and gggGary like this.
  13. kevski

    kevski XS650 Addict

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    Sadly I did not build the motor, I have already sourced a used head which came today, and I must say i am happy with it as there is no wear on the valve tips, seats and valves are good with no pitting so will be lapped in, guides are in spec, only thing is a 6mm tappet cover stud is stripped out, possibly the reason it has not seen much wear, very little carbon in combustion chambers, I shall make a 7mm to 6mm shouldered stud for this, in a week or two it will be running again, then i shall rebuild the old head.
     
    thuban, Jim, grizld1 and 1 other person like this.
  14. grizld1

    grizld1 Grumpy old man Top Contributor

    Congrats on your outlook, kevski--no venting, putting the losses behind you and moving forward.

    Hey Jack, don't be calling a product from Saint Jerry Heiden "complete junk," you risk being charged with heresy and flamed like me! You ought to know that an accomplished tuner and builder would never, ever hawk inferior goods on the strength of his reputation, just to make a buck.
     
    Jim likes this.
  15. Jack

    Jack XS650 Junkie Top Contributor

    If you're gonna throttle it,you'll need a good valve spring to keep the valves in check from bouncing off the seat.Here is the valve spring I spoke of and retainer. You can run a 420 lift cam with the set up if you choose to do so
    The springs can be bought for about $11.00 US and retainers $50.00 nad are much stronger than stock and lighter. moly retainer.jpg moly retainer 2.jpg 20200429_141833.jpg
     

    Attached Files:

    Jim likes this.
  16. kevski

    kevski XS650 Addict

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    I certainly will not bad mouth builders, suppliers or products that have been around for years on the strength that a part sometimes fails, I have known some of the so called best in the world fail with far more dire consequences, as it is it can be remedied and will be back.
     
    grizld1 and GLJ like this.
  17. Jack

    Jack XS650 Junkie Top Contributor

    Griz, I have nothing against Jerry but there's enough information out there with problems with those valves and from what I've seen in person nor
    do I care what 650traders opinions are as I will continue to advise members of this forum what products to avoid based on my experience and of others
    misfortunes. There's a reason why Hoos Racing uses kibblewhite valves ,they're a higher quality valve and the tulip head is based off the Harry Lillie
    Harley valves.
     
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  18. grizld1

    grizld1 Grumpy old man Top Contributor

    We both call 'em like we see 'em, Jack. Have you had a chance to run that XS Performance camshaft yet? Make sure your dental insurance is paid up before you do, that thing will shake your fillings out!
     
    buzzword, thuban and Jim like this.
  19. Jack

    Jack XS650 Junkie Top Contributor

    Nobody is bad mouthing anybody but advising you to avoid certain products due to inferior quality and in the end it's up to you how you spend your money,that's what forums are for to guide you in the right direction to avoid engine failures.
     
    Jim likes this.
  20. Jack

    Jack XS650 Junkie Top Contributor

    Haven't decided what to do with that clone door stop yet,besides your experience and from others,I've also read that the cam lobes are soft causing excessive wear.
     
    grizld1 and Jim like this.

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